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Schedule III - Real Estate and Accumulated Depreciation (Detail) (USD $) In Thousands, unless otherwise specified | 12 Months Ended |  |  |
--- | --- | --- | --- | ---
Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012 | Dec. 31, 2011
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances | $ 599,985 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances |  |  |
Initial Cost of Land | 743,319 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand |  |  |
Building and Improvements | 1,635,277 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 779,479 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements |  |  |
Land | 718,188 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand |  |  |
Building and improvements | 2,439,887 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements |  |  |
Total | 3,158,075 us-gaap_RealEstateGrossAtCarryingValue |  |  |
Accumulated depreciation 12/31/2012 | 786,978 us-gaap_RealEstateAccumulatedDepreciation | 748,044 us-gaap_RealEstateAccumulatedDepreciation | 735,593 us-gaap_RealEstateAccumulatedDepreciation | 695,931 us-gaap_RealEstateAccumulatedDepreciation
4250 River Green Parkway [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Duluth, GA |  |  |
Initial Cost of Land | 264 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourTwoFiveZeroRiverGreenParkwayMember |  |  |
Building and Improvements | 1,522 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourTwoFiveZeroRiverGreenParkwayMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 82 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourTwoFiveZeroRiverGreenParkwayMember |  |  |
Land | 214 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourTwoFiveZeroRiverGreenParkwayMember |  |  |
Building and improvements | 1,654 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourTwoFiveZeroRiverGreenParkwayMember |  |  |
Total | 1,868 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourTwoFiveZeroRiverGreenParkwayMember |  |  |
Accumulated depreciation 12/31/2012 | 871 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourTwoFiveZeroRiverGreenParkwayMember |  |  |
1650 Highway 155 [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | McDonough, GA |  |  |
Initial Cost of Land | 788 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixFiveZeroHighwayOneFiveFiveMember |  |  |
Building and Improvements | 4,544 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixFiveZeroHighwayOneFiveFiveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (363)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixFiveZeroHighwayOneFiveFiveMember |  |  |
Land | 365 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixFiveZeroHighwayOneFiveFiveMember |  |  |
Building and improvements | 4,604 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixFiveZeroHighwayOneFiveFiveMember |  |  |
Total | 4,969 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixFiveZeroHighwayOneFiveFiveMember |  |  |
Accumulated depreciation 12/31/2012 | 2,602 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixFiveZeroHighwayOneFiveFiveMember |  |  |
1665 Dogwood [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Conyers, GA |  |  |
Initial Cost of Land | 635 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixSixFiveDogwoodDriveMember |  |  |
Building and Improvements | 3,662 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixSixFiveDogwoodDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 972 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixSixFiveDogwoodDriveMember |  |  |
Land | 635 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixSixFiveDogwoodDriveMember |  |  |
Building and improvements | 4,634 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixSixFiveDogwoodDriveMember |  |  |
Total | 5,269 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixSixFiveDogwoodDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 2,230 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixSixFiveDogwoodDriveMember |  |  |
1715 Dogwood [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Conyers, GA |  |  |
Initial Cost of Land | 288 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenOneFiveDogwoodMember |  |  |
Building and Improvements | 1,675 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenOneFiveDogwoodMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 827 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenOneFiveDogwoodMember |  |  |
Land | 228 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenOneFiveDogwoodMember |  |  |
Building and improvements | 2,562 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenOneFiveDogwoodMember |  |  |
Total | 2,790 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenOneFiveDogwoodMember |  |  |
Accumulated depreciation 12/31/2012 | 1,052 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenOneFiveDogwoodMember |  |  |
11235 Harland Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Covington, GA |  |  |
Initial Cost of Land | 125 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneTwoThreeFiveHarlandDriveMember |  |  |
Building and Improvements | 739 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneTwoThreeFiveHarlandDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 218 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneTwoThreeFiveHarlandDriveMember |  |  |
Land | 125 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneTwoThreeFiveHarlandDriveMember |  |  |
Building and improvements | 957 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneTwoThreeFiveHarlandDriveMember |  |  |
Total | 1,082 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneTwoThreeFiveHarlandDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 433 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneTwoThreeFiveHarlandDriveMember |  |  |
4051 Southmeadow Parkway [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Atlanta, GA |  |  |
Initial Cost of Land | 726 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourZeroFiveOneSouthmeadowParkwayMember |  |  |
Building and Improvements | 4,130 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourZeroFiveOneSouthmeadowParkwayMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 880 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourZeroFiveOneSouthmeadowParkwayMember |  |  |
Land | 726 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourZeroFiveOneSouthmeadowParkwayMember |  |  |
Building and improvements | 5,010 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourZeroFiveOneSouthmeadowParkwayMember |  |  |
Total | 5,736 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourZeroFiveOneSouthmeadowParkwayMember |  |  |
Accumulated depreciation 12/31/2012 | 2,366 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourZeroFiveOneSouthmeadowParkwayMember |  |  |
4071 Southmeadow Parkway [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Atlanta, GA |  |  |
Initial Cost of Land | 750 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourZeroSevenOneSouthmeadowParkwayMember |  |  |
Building and Improvements | 4,460 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourZeroSevenOneSouthmeadowParkwayMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,742 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourZeroSevenOneSouthmeadowParkwayMember |  |  |
Land | 828 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourZeroSevenOneSouthmeadowParkwayMember |  |  |
Building and improvements | 6,124 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourZeroSevenOneSouthmeadowParkwayMember |  |  |
Total | 6,952 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourZeroSevenOneSouthmeadowParkwayMember |  |  |
Accumulated depreciation 12/31/2012 | 2,919 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourZeroSevenOneSouthmeadowParkwayMember |  |  |
4081 Southmeadow Parkway [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Atlanta, GA |  |  |
Initial Cost of Land | 1,012 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourZeroEightOneSouthmeadowParkwayMember |  |  |
Building and Improvements | 5,918 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourZeroEightOneSouthmeadowParkwayMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,796 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourZeroEightOneSouthmeadowParkwayMember |  |  |
Land | 1,157 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourZeroEightOneSouthmeadowParkwayMember |  |  |
Building and improvements | 7,569 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourZeroEightOneSouthmeadowParkwayMember |  |  |
Total | 8,726 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourZeroEightOneSouthmeadowParkwayMember |  |  |
Accumulated depreciation 12/31/2012 | 3,409 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourZeroEightOneSouthmeadowParkwayMember |  |  |
5570 Tulane Dr [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Atlanta, GA |  |  |
Encumbrances | 2,218 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveSevenZeroTulaneDriveDMember |  |  |
Initial Cost of Land | 527 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveSevenZeroTulaneDriveDMember |  |  |
Building and Improvements | 2,984 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveSevenZeroTulaneDriveDMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,184 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveSevenZeroTulaneDriveDMember |  |  |
Land | 546 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveSevenZeroTulaneDriveDMember |  |  |
Building and improvements | 4,149 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveSevenZeroTulaneDriveDMember |  |  |
Total | 4,695 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveSevenZeroTulaneDriveDMember |  |  |
Accumulated depreciation 12/31/2012 | 1,694 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveSevenZeroTulaneDriveDMember |  |  |
955 Cobb Place [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Kennesaw, GA |  |  |
Encumbrances | 2,895 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineFiveFiveCobbPlaceMember |  |  |
Initial Cost of Land | 780 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineFiveFiveCobbPlaceMember |  |  |
Building and Improvements | 4,420 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineFiveFiveCobbPlaceMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 927 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineFiveFiveCobbPlaceMember |  |  |
Land | 804 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineFiveFiveCobbPlaceMember |  |  |
Building and improvements | 5,323 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineFiveFiveCobbPlaceMember |  |  |
Total | 6,127 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineFiveFiveCobbPlaceMember |  |  |
Accumulated depreciation 12/31/2012 | 2,100 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineFiveFiveCobbPlaceMember |  |  |
1005 Sigman Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Conyers, GA |  |  |
Encumbrances | 2,127 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroZeroFiveSigmanRoadMember |  |  |
Initial Cost of Land | 566 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroZeroFiveSigmanRoadMember |  |  |
Building and Improvements | 3,134 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroZeroFiveSigmanRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 433 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroZeroFiveSigmanRoadMember |  |  |
Land | 574 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroZeroFiveSigmanRoadMember |  |  |
Building and improvements | 3,559 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroZeroFiveSigmanRoadMember |  |  |
Total | 4,133 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroZeroFiveSigmanRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 1,318 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroZeroFiveSigmanRoadMember |  |  |
2050 East Park Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Conyers, GA |  |  |
Initial Cost of Land | 452 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroFiveZeroEastParkDriveMember |  |  |
Building and Improvements | 2,504 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroFiveZeroEastParkDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 151 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroFiveZeroEastParkDriveMember |  |  |
Land | 459 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroFiveZeroEastParkDriveMember |  |  |
Building and improvements | 2,648 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroFiveZeroEastParkDriveMember |  |  |
Total | 3,107 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroFiveZeroEastParkDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 998 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroFiveZeroEastParkDriveMember |  |  |
1256 Oakbrook Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Norcross, GA |  |  |
Initial Cost of Land | 336 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoFiveSixOakbrookDriveMember |  |  |
Building and Improvements | 1,907 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoFiveSixOakbrookDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 340 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoFiveSixOakbrookDriveMember |  |  |
Land | 339 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoFiveSixOakbrookDriveMember |  |  |
Building and improvements | 2,244 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoFiveSixOakbrookDriveMember |  |  |
Total | 2,583 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoFiveSixOakbrookDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 744 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoFiveSixOakbrookDriveMember |  |  |
1265 Oakbrook Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Norcross, GA |  |  |
Initial Cost of Land | 307 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSixFiveOakbrookDriveMember |  |  |
Building and Improvements | 1,742 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSixFiveOakbrookDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 335 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSixFiveOakbrookDriveMember |  |  |
Land | 309 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSixFiveOakbrookDriveMember |  |  |
Building and improvements | 2,075 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSixFiveOakbrookDriveMember |  |  |
Total | 2,384 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSixFiveOakbrookDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 698 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSixFiveOakbrookDriveMember |  |  |
1280 Oakbrook Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Norcross, GA |  |  |
Initial Cost of Land | 281 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoEightZeroOakbrookDriveMember |  |  |
Building and Improvements | 1,592 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoEightZeroOakbrookDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 286 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoEightZeroOakbrookDriveMember |  |  |
Land | 283 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoEightZeroOakbrookDriveMember |  |  |
Building and improvements | 1,876 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoEightZeroOakbrookDriveMember |  |  |
Total | 2,159 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoEightZeroOakbrookDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 624 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoEightZeroOakbrookDriveMember |  |  |
1300 Oakbrook Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Norcross, GA |  |  |
Initial Cost of Land | 420 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeZeroZeroOakbrookDriveMember |  |  |
Building and Improvements | 2,381 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeZeroZeroOakbrookDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 254 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeZeroZeroOakbrookDriveMember |  |  |
Land | 423 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeZeroZeroOakbrookDriveMember |  |  |
Building and improvements | 2,632 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeZeroZeroOakbrookDriveMember |  |  |
Total | 3,055 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeZeroZeroOakbrookDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 866 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeZeroZeroOakbrookDriveMember |  |  |
1325 Oakbrook Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Norcross, GA |  |  |
Initial Cost of Land | 332 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeTwoFiveOakbrookDriveMember |  |  |
Building and Improvements | 1,879 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeTwoFiveOakbrookDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 338 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeTwoFiveOakbrookDriveMember |  |  |
Land | 334 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeTwoFiveOakbrookDriveMember |  |  |
Building and improvements | 2,215 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeTwoFiveOakbrookDriveMember |  |  |
Total | 2,549 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeTwoFiveOakbrookDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 743 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeTwoFiveOakbrookDriveMember |  |  |
1351 Oakbrook Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Norcross, GA |  |  |
Initial Cost of Land | 370 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFiveOneOakbrookDriveMember |  |  |
Building and Improvements | 2,099 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFiveOneOakbrookDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (1,020)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFiveOneOakbrookDriveMember |  |  |
Land | 146 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFiveOneOakbrookDriveMember |  |  |
Building and improvements | 1,303 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFiveOneOakbrookDriveMember |  |  |
Total | 1,449 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFiveOneOakbrookDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 626 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFiveOneOakbrookDriveMember |  |  |
1346 Oakbrook Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Norcross, GA |  |  |
Initial Cost of Land | 740 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFourSixOakbrookDriveMember |  |  |
Building and Improvements | 4,192 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFourSixOakbrookDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (684)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFourSixOakbrookDriveMember |  |  |
Land | 352 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFourSixOakbrookDriveMember |  |  |
Building and improvements | 3,896 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFourSixOakbrookDriveMember |  |  |
Total | 4,248 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFourSixOakbrookDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,925 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFourSixOakbrookDriveMember |  |  |
3060 South Park Blvd [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Ellenwood, GA |  |  |
Initial Cost of Land | 1,600 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroSixZeroSouthParkBlvdMember |  |  |
Building and Improvements | 12,464 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroSixZeroSouthParkBlvdMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 2,691 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroSixZeroSouthParkBlvdMember |  |  |
Land | 1,604 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroSixZeroSouthParkBlvdMember |  |  |
Building and improvements | 15,151 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroSixZeroSouthParkBlvdMember |  |  |
Total | 16,755 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroSixZeroSouthParkBlvdMember |  |  |
Accumulated depreciation 12/31/2012 | 4,306 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroSixZeroSouthParkBlvdMember |  |  |
Greenwood Industrial Park [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | McDonough, GA |  |  |
Encumbrances | 4,338 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_GreenwoodIndustrialParkMember |  |  |
Initial Cost of Land | 1,550 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_GreenwoodIndustrialParkMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 7,632 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_GreenwoodIndustrialParkMember |  |  |
Land | 1,550 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_GreenwoodIndustrialParkMember |  |  |
Building and improvements | 7,632 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_GreenwoodIndustrialParkMember |  |  |
Total | 9,182 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_GreenwoodIndustrialParkMember |  |  |
Accumulated depreciation 12/31/2012 | 1,943 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_GreenwoodIndustrialParkMember |  |  |
46 Kent Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Cartersville GA |  |  |
Encumbrances | 1,415 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSixKentDriveMember |  |  |
Initial Cost of Land | 794 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSixKentDriveMember |  |  |
Building and Improvements | 2,252 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSixKentDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (52)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSixKentDriveMember |  |  |
Land | 798 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSixKentDriveMember |  |  |
Building and improvements | 2,196 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSixKentDriveMember |  |  |
Total | 2,994 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSixKentDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 770 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSixKentDriveMember |  |  |
605 Stonehill Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Atlanta, GA |  |  |
Initial Cost of Land | 485 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixZeroFiveStonehillDriveMember |  |  |
Building and Improvements | 1,979 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixZeroFiveStonehillDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (23)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixZeroFiveStonehillDriveMember |  |  |
Land | 490 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixZeroFiveStonehillDriveMember |  |  |
Building and improvements | 1,951 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixZeroFiveStonehillDriveMember |  |  |
Total | 2,441 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixZeroFiveStonehillDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,704 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixZeroFiveStonehillDriveMember |  |  |
5095 Phillip Lee Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Atlanta, GA |  |  |
Encumbrances | 4,885 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroNineFivePhillipLeeDriveMember |  |  |
Initial Cost of Land | 735 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroNineFivePhillipLeeDriveMember |  |  |
Building and Improvements | 3,627 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroNineFivePhillipLeeDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 485 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroNineFivePhillipLeeDriveMember |  |  |
Land | 740 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroNineFivePhillipLeeDriveMember |  |  |
Building and improvements | 4,107 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroNineFivePhillipLeeDriveMember |  |  |
Total | 4,847 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroNineFivePhillipLeeDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 2,358 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroNineFivePhillipLeeDriveMember |  |  |
6514 Warren Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Norcross, GA |  |  |
Initial Cost of Land | 510 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveOneFourWarrenDriveMember |  |  |
Building and Improvements | 1,250 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveOneFourWarrenDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 127 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveOneFourWarrenDriveMember |  |  |
Land | 513 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveOneFourWarrenDriveMember |  |  |
Building and improvements | 1,374 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveOneFourWarrenDriveMember |  |  |
Total | 1,887 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveOneFourWarrenDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 454 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveOneFourWarrenDriveMember |  |  |
6544 Warren Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Norcross, GA |  |  |
Initial Cost of Land | 711 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveFourFourWarrenDriveMember |  |  |
Building and Improvements | 2,310 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveFourFourWarrenDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 293 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveFourFourWarrenDriveMember |  |  |
Land | 715 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveFourFourWarrenDriveMember |  |  |
Building and improvements | 2,599 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveFourFourWarrenDriveMember |  |  |
Total | 3,314 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveFourFourWarrenDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 906 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveFourFourWarrenDriveMember |  |  |
5356 E. Ponce De Leon [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Stone Mountain, GA |  |  |
Initial Cost of Land | 604 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThreeFiveSixEPonceDeLeonMember |  |  |
Building and Improvements | 3,888 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThreeFiveSixEPonceDeLeonMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 90 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThreeFiveSixEPonceDeLeonMember |  |  |
Land | 610 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThreeFiveSixEPonceDeLeonMember |  |  |
Building and improvements | 3,972 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThreeFiveSixEPonceDeLeonMember |  |  |
Total | 4,582 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThreeFiveSixEPonceDeLeonMember |  |  |
Accumulated depreciation 12/31/2012 | 1,811 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThreeFiveSixEPonceDeLeonMember |  |  |
5390 E. Ponce De Leon [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Stone Mountain, GA |  |  |
Initial Cost of Land | 397 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThreeNineZeroEPonceDeLeonMember |  |  |
Building and Improvements | 1,791 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThreeNineZeroEPonceDeLeonMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 108 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThreeNineZeroEPonceDeLeonMember |  |  |
Land | 402 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThreeNineZeroEPonceDeLeonMember |  |  |
Building and improvements | 1,894 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThreeNineZeroEPonceDeLeonMember |  |  |
Total | 2,296 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThreeNineZeroEPonceDeLeonMember |  |  |
Accumulated depreciation 12/31/2012 | 705 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThreeNineZeroEPonceDeLeonMember |  |  |
195 & 197 Collins Boulevard [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Athens, GA |  |  |
Initial Cost of Land | 1,410 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineFiveAndOneNineSevenCollinsBoulevardMember |  |  |
Building and Improvements | 5,344 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineFiveAndOneNineSevenCollinsBoulevardMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 896 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineFiveAndOneNineSevenCollinsBoulevardMember |  |  |
Land | 989 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineFiveAndOneNineSevenCollinsBoulevardMember |  |  |
Building and improvements | 6,661 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineFiveAndOneNineSevenCollinsBoulevardMember |  |  |
Total | 7,650 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineFiveAndOneNineSevenCollinsBoulevardMember |  |  |
Accumulated depreciation 12/31/2012 | 3,516 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineFiveAndOneNineSevenCollinsBoulevardMember |  |  |
1755 Enterprise Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Buford, GA |  |  |
Encumbrances | 1,242 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenFiveFiveEnterpriseDriveMember |  |  |
Initial Cost of Land | 712 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenFiveFiveEnterpriseDriveMember |  |  |
Building and Improvements | 2,118 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenFiveFiveEnterpriseDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (202)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenFiveFiveEnterpriseDriveMember |  |  |
Land | 716 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenFiveFiveEnterpriseDriveMember |  |  |
Building and improvements | 1,912 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenFiveFiveEnterpriseDriveMember |  |  |
Total | 2,628 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenFiveFiveEnterpriseDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 618 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenFiveFiveEnterpriseDriveMember |  |  |
4555 Atwater Court [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Buford, GA |  |  |
Encumbrances | 2,235 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveFiveFiveAtwaterCourtMember |  |  |
Initial Cost of Land | 881 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveFiveFiveAtwaterCourtMember |  |  |
Building and Improvements | 3,550 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveFiveFiveAtwaterCourtMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 298 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveFiveFiveAtwaterCourtMember |  |  |
Land | 885 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveFiveFiveAtwaterCourtMember |  |  |
Building and improvements | 3,844 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveFiveFiveAtwaterCourtMember |  |  |
Total | 4,729 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveFiveFiveAtwaterCourtMember |  |  |
Accumulated depreciation 12/31/2012 | 1,048 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveFiveFiveAtwaterCourtMember |  |  |
80 Liberty Industrial Parkway [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | McDonough, GA |  |  |
Initial Cost of Land | 756 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightZeroLibertyIndustrialParkwayMember |  |  |
Building and Improvements | 3,695 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightZeroLibertyIndustrialParkwayMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (1,244)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightZeroLibertyIndustrialParkwayMember |  |  |
Land | 467 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightZeroLibertyIndustrialParkwayMember |  |  |
Building and improvements | 2,740 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightZeroLibertyIndustrialParkwayMember |  |  |
Total | 3,207 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightZeroLibertyIndustrialParkwayMember |  |  |
Accumulated depreciation 12/31/2012 | 902 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightZeroLibertyIndustrialParkwayMember |  |  |
596 Bonnie Valentine [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Pendergrass, GA |  |  |
Initial Cost of Land | 2,580 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveNineSixBonnieValentineMember |  |  |
Building and Improvements | 21,730 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveNineSixBonnieValentineMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 3,675 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveNineSixBonnieValentineMember |  |  |
Land | 2,594 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveNineSixBonnieValentineMember |  |  |
Building and improvements | 25,391 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveNineSixBonnieValentineMember |  |  |
Total | 27,985 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveNineSixBonnieValentineMember |  |  |
Accumulated depreciation 12/31/2012 | 5,939 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveNineSixBonnieValentineMember |  |  |
11415 Old Roswell Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Alpharetta, GA |  |  |
Encumbrances | 3,126 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFourOneFiveOldRoswellRoadMember |  |  |
Initial Cost of Land | 2,403 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFourOneFiveOldRoswellRoadMember |  |  |
Building and Improvements | 1,912 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFourOneFiveOldRoswellRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 628 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFourOneFiveOldRoswellRoadMember |  |  |
Land | 2,428 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFourOneFiveOldRoswellRoadMember |  |  |
Building and improvements | 2,515 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFourOneFiveOldRoswellRoadMember |  |  |
Total | 4,943 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFourOneFiveOldRoswellRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 963 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFourOneFiveOldRoswellRoadMember |  |  |
9700 Martin Luther King Hwy [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Lanham, MD |  |  |
Initial Cost of Land | 700 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandSevenHundredMartinLutherKingHwyMember |  |  |
Building and Improvements | 1,920 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandSevenHundredMartinLutherKingHwyMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 742 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandSevenHundredMartinLutherKingHwyMember |  |  |
Land | 700 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandSevenHundredMartinLutherKingHwyMember |  |  |
Building and improvements | 2,662 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandSevenHundredMartinLutherKingHwyMember |  |  |
Total | 3,362 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandSevenHundredMartinLutherKingHwyMember |  |  |
Accumulated depreciation 12/31/2012 | 1,103 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandSevenHundredMartinLutherKingHwyMember |  |  |
9730 Martin Luther King Hwy [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Lanham, MD |  |  |
Initial Cost of Land | 500 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandSevenHundredThirtyMartinLutherKingHwyMember |  |  |
Building and Improvements | 955 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandSevenHundredThirtyMartinLutherKingHwyMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 535 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandSevenHundredThirtyMartinLutherKingHwyMember |  |  |
Land | 500 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandSevenHundredThirtyMartinLutherKingHwyMember |  |  |
Building and improvements | 1,490 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandSevenHundredThirtyMartinLutherKingHwyMember |  |  |
Total | 1,990 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandSevenHundredThirtyMartinLutherKingHwyMember |  |  |
Accumulated depreciation 12/31/2012 | 581 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandSevenHundredThirtyMartinLutherKingHwyMember |  |  |
4621 Boston Way [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Lanham, MD |  |  |
Initial Cost of Land | 1,100 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandSixHundredTwentyOneBostonWayMember |  |  |
Building and Improvements | 3,070 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandSixHundredTwentyOneBostonWayMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 517 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandSixHundredTwentyOneBostonWayMember |  |  |
Land | 1,100 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandSixHundredTwentyOneBostonWayMember |  |  |
Building and improvements | 3,587 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandSixHundredTwentyOneBostonWayMember |  |  |
Total | 4,687 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandSixHundredTwentyOneBostonWayMember |  |  |
Accumulated depreciation 12/31/2012 | 1,338 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandSixHundredTwentyOneBostonWayMember |  |  |
4720 Boston Way [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Lanham, MD |  |  |
Initial Cost of Land | 1,200 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandSevenHundredTwentyBostonWayMember |  |  |
Building and Improvements | 2,174 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandSevenHundredTwentyBostonWayMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 792 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandSevenHundredTwentyBostonWayMember |  |  |
Land | 1,200 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandSevenHundredTwentyBostonWayMember |  |  |
Building and improvements | 2,966 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandSevenHundredTwentyBostonWayMember |  |  |
Total | 4,166 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandSevenHundredTwentyBostonWayMember |  |  |
Accumulated depreciation 12/31/2012 | 1,047 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandSevenHundredTwentyBostonWayMember |  |  |
22520 Randolph Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Dulles, VA |  |  |
Initial Cost of Land | 3,200 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwentyTwoThousandFiveHundredTwentyRandolphDriveDullesMember |  |  |
Building and Improvements | 8,187 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwentyTwoThousandFiveHundredTwentyRandolphDriveDullesMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (656)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwentyTwoThousandFiveHundredTwentyRandolphDriveDullesMember |  |  |
Land | 3,208 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwentyTwoThousandFiveHundredTwentyRandolphDriveDullesMember |  |  |
Building and improvements | 7,523 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwentyTwoThousandFiveHundredTwentyRandolphDriveDullesMember |  |  |
Total | 10,731 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwentyTwoThousandFiveHundredTwentyRandolphDriveDullesMember |  |  |
Accumulated depreciation 12/31/2012 | 1,675 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwentyTwoThousandFiveHundredTwentyRandolphDriveDullesMember |  |  |
22630 Dulles Summit Court [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Dulles, VA |  |  |
Initial Cost of Land | 2,200 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwentyTwoThousandSixHundredThirtyDullesSummitCourtMember |  |  |
Building and Improvements | 9,346 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwentyTwoThousandSixHundredThirtyDullesSummitCourtMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (820)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwentyTwoThousandSixHundredThirtyDullesSummitCourtMember |  |  |
Land | 2,206 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwentyTwoThousandSixHundredThirtyDullesSummitCourtMember |  |  |
Building and improvements | 8,520 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwentyTwoThousandSixHundredThirtyDullesSummitCourtMember |  |  |
Total | 10,726 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwentyTwoThousandSixHundredThirtyDullesSummitCourtMember |  |  |
Accumulated depreciation 12/31/2012 | 1,994 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwentyTwoThousandSixHundredThirtyDullesSummitCourtMember |  |  |
4201 Forbes Boulevard [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Lanham, MD |  |  |
Initial Cost of Land | 356 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandTwoHundredOneForbesBoulevardMember |  |  |
Building and Improvements | 1,823 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandTwoHundredOneForbesBoulevardMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 186 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandTwoHundredOneForbesBoulevardMember |  |  |
Land | 375 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandTwoHundredOneForbesBoulevardMember |  |  |
Building and improvements | 1,990 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandTwoHundredOneForbesBoulevardMember |  |  |
Total | 2,365 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandTwoHundredOneForbesBoulevardMember |  |  |
Accumulated depreciation 12/31/2012 | 586 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandTwoHundredOneForbesBoulevardMember |  |  |
4370-4383 Lottsford Vista Rd [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Lanham, MD |  |  |
Initial Cost of Land | 279 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandThreeHundredSeventyAndFourThousandThreeHundredEightyThreeLottsfordVistaRdMember |  |  |
Building and Improvements | 1,358 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandThreeHundredSeventyAndFourThousandThreeHundredEightyThreeLottsfordVistaRdMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 89 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandThreeHundredSeventyAndFourThousandThreeHundredEightyThreeLottsfordVistaRdMember |  |  |
Land | 296 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandThreeHundredSeventyAndFourThousandThreeHundredEightyThreeLottsfordVistaRdMember |  |  |
Building and improvements | 1,430 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandThreeHundredSeventyAndFourThousandThreeHundredEightyThreeLottsfordVistaRdMember |  |  |
Total | 1,726 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandThreeHundredSeventyAndFourThousandThreeHundredEightyThreeLottsfordVistaRdMember |  |  |
Accumulated depreciation 12/31/2012 | 325 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandThreeHundredSeventyAndFourThousandThreeHundredEightyThreeLottsfordVistaRdMember |  |  |
4400 Lottsford Vista Rd [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Lanham, MD |  |  |
Initial Cost of Land | 351 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandFourHundredLottsfordVistaRdMember |  |  |
Building and Improvements | 1,955 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandFourHundredLottsfordVistaRdMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 241 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandFourHundredLottsfordVistaRdMember |  |  |
Land | 372 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandFourHundredLottsfordVistaRdMember |  |  |
Building and improvements | 2,175 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandFourHundredLottsfordVistaRdMember |  |  |
Total | 2,547 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandFourHundredLottsfordVistaRdMember |  |  |
Accumulated depreciation 12/31/2012 | 581 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandFourHundredLottsfordVistaRdMember |  |  |
4420 Lottsford Vista Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Lanham, MD |  |  |
Initial Cost of Land | 539 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandFourHundredTwentyLottsfordVistaRoadMember |  |  |
Building and Improvements | 2,196 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandFourHundredTwentyLottsfordVistaRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 6 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandFourHundredTwentyLottsfordVistaRoadMember |  |  |
Land | 568 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandFourHundredTwentyLottsfordVistaRoadMember |  |  |
Building and improvements | 2,173 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandFourHundredTwentyLottsfordVistaRoadMember |  |  |
Total | 2,741 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandFourHundredTwentyLottsfordVistaRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 587 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandFourHundredTwentyLottsfordVistaRoadMember |  |  |
11204 McCormick Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Hunt Valley, MD |  |  |
Initial Cost of Land | 1,017 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ElevenThousandTwoHundredFourMcCormickRoadMember |  |  |
Building and Improvements | 3,132 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ElevenThousandTwoHundredFourMcCormickRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (59)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ElevenThousandTwoHundredFourMcCormickRoadMember |  |  |
Land | 1,038 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ElevenThousandTwoHundredFourMcCormickRoadMember |  |  |
Building and improvements | 3,052 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ElevenThousandTwoHundredFourMcCormickRoadMember |  |  |
Total | 4,090 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ElevenThousandTwoHundredFourMcCormickRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 1,184 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ElevenThousandTwoHundredFourMcCormickRoadMember |  |  |
11110 Pepper Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Hunt Valley, MD |  |  |
Initial Cost of Land | 918 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ElevenThousandOneHundredTenPepperRoadMember |  |  |
Building and Improvements | 2,529 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ElevenThousandOneHundredTenPepperRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 281 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ElevenThousandOneHundredTenPepperRoadMember |  |  |
Land | 938 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ElevenThousandOneHundredTenPepperRoadMember |  |  |
Building and improvements | 2,790 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ElevenThousandOneHundredTenPepperRoadMember |  |  |
Total | 3,728 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ElevenThousandOneHundredTenPepperRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 1,012 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ElevenThousandOneHundredTenPepperRoadMember |  |  |
11100-11120 Gilroy Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Hunt Valley, MD |  |  |
Initial Cost of Land | 901 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ElevenThousandOneHundredAndElevenThousandOneHundredTwentyGilroyRoadMember |  |  |
Building and Improvements | 1,455 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ElevenThousandOneHundredAndElevenThousandOneHundredTwentyGilroyRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 166 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ElevenThousandOneHundredAndElevenThousandOneHundredTwentyGilroyRoadMember |  |  |
Land | 919 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ElevenThousandOneHundredAndElevenThousandOneHundredTwentyGilroyRoadMember |  |  |
Building and improvements | 1,603 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ElevenThousandOneHundredAndElevenThousandOneHundredTwentyGilroyRoadMember |  |  |
Total | 2,522 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ElevenThousandOneHundredAndElevenThousandOneHundredTwentyGilroyRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 569 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ElevenThousandOneHundredAndElevenThousandOneHundredTwentyGilroyRoadMember |  |  |
318 Clubhouse Lane [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Hunt Valley, MD |  |  |
Initial Cost of Land | 701 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredEighteenClubhouseLaneMember |  |  |
Building and Improvements | 1,691 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredEighteenClubhouseLaneMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (106)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredEighteenClubhouseLaneMember |  |  |
Land | 718 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredEighteenClubhouseLaneMember |  |  |
Building and improvements | 1,568 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredEighteenClubhouseLaneMember |  |  |
Total | 2,286 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredEighteenClubhouseLaneMember |  |  |
Accumulated depreciation 12/31/2012 | 532 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredEighteenClubhouseLaneMember |  |  |
10709 Gilroy Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Hunt Valley, MD |  |  |
Encumbrances | 2,348 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TenThousandSevenHundredNineGilroyRoadMember |  |  |
Initial Cost of Land | 913 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TenThousandSevenHundredNineGilroyRoadMember |  |  |
Building and Improvements | 2,705 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TenThousandSevenHundredNineGilroyRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (143)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TenThousandSevenHundredNineGilroyRoadMember |  |  |
Land | 913 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TenThousandSevenHundredNineGilroyRoadMember |  |  |
Building and improvements | 2,562 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TenThousandSevenHundredNineGilroyRoadMember |  |  |
Total | 3,475 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TenThousandSevenHundredNineGilroyRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 1,172 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TenThousandSevenHundredNineGilroyRoadMember |  |  |
10707 Gilroy Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Hunt Valley, MD |  |  |
Initial Cost of Land | 1,111 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TenThousandSevenHundredSevenGilroyRoadMember |  |  |
Building and Improvements | 3,819 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TenThousandSevenHundredSevenGilroyRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 502 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TenThousandSevenHundredSevenGilroyRoadMember |  |  |
Land | 1,136 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TenThousandSevenHundredSevenGilroyRoadMember |  |  |
Building and improvements | 4,296 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TenThousandSevenHundredSevenGilroyRoadMember |  |  |
Total | 5,432 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TenThousandSevenHundredSevenGilroyRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 1,491 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TenThousandSevenHundredSevenGilroyRoadMember |  |  |
38 Loveton Circle [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Sparks, MD |  |  |
Initial Cost of Land | 1,648 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThirtyEightLovetonCircleMember |  |  |
Building and Improvements | 2,151 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThirtyEightLovetonCircleMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (241)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThirtyEightLovetonCircleMember |  |  |
Land | 1,690 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThirtyEightLovetonCircleMember |  |  |
Building and improvements | 1,868 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThirtyEightLovetonCircleMember |  |  |
Total | 3,558 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThirtyEightLovetonCircleMember |  |  |
Accumulated depreciation 12/31/2012 | 722 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThirtyEightLovetonCircleMember |  |  |
1225 Bengies Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Baltimore, MD |  |  |
Initial Cost of Land | 2,640 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandTwoHundredTwentyFiveBengiesRoadMember |  |  |
Building and Improvements | 270 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandTwoHundredTwentyFiveBengiesRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 14,041 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandTwoHundredTwentyFiveBengiesRoadMember |  |  |
Land | 2,823 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandTwoHundredTwentyFiveBengiesRoadMember |  |  |
Building and improvements | 14,128 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandTwoHundredTwentyFiveBengiesRoadMember |  |  |
Total | 16,951 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandTwoHundredTwentyFiveBengiesRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 3,352 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandTwoHundredTwentyFiveBengiesRoadMember |  |  |
1214-B Freedom Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Cranberry Township, PA |  |  |
Encumbrances | 1,359 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandTwoHundredAndFourteenBFreedomRoadMember |  |  |
Initial Cost of Land | 31 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandTwoHundredAndFourteenBFreedomRoadMember |  |  |
Building and Improvements | 994 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandTwoHundredAndFourteenBFreedomRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 613 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandTwoHundredAndFourteenBFreedomRoadMember |  |  |
Land | 200 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandTwoHundredAndFourteenBFreedomRoadMember |  |  |
Building and improvements | 1,438 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandTwoHundredAndFourteenBFreedomRoadMember |  |  |
Total | 1,638 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandTwoHundredAndFourteenBFreedomRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 1,191 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandTwoHundredAndFourteenBFreedomRoadMember |  |  |
401 Russell Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Middletown, PA |  |  |
Initial Cost of Land | 262 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredOneRussellDriveMember |  |  |
Building and Improvements | 857 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredOneRussellDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,696 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredOneRussellDriveMember |  |  |
Land | 287 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredOneRussellDriveMember |  |  |
Building and improvements | 2,528 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredOneRussellDriveMember |  |  |
Total | 2,815 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredOneRussellDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,891 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredOneRussellDriveMember |  |  |
2700 Commerce Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Middletown, PA |  |  |
Initial Cost of Land | 196 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandSevenHundredCommerceDriveMember |  |  |
Building and Improvements | 997 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandSevenHundredCommerceDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 935 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandSevenHundredCommerceDriveMember |  |  |
Land | 206 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandSevenHundredCommerceDriveMember |  |  |
Building and improvements | 1,922 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandSevenHundredCommerceDriveMember |  |  |
Total | 2,128 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandSevenHundredCommerceDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,421 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandSevenHundredCommerceDriveMember |  |  |
2701 Commerce Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Middletown, PA |  |  |
Encumbrances | 1,884 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandSevenHundredAndOneCommerceDriveMember |  |  |
Initial Cost of Land | 141 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandSevenHundredAndOneCommerceDriveMember |  |  |
Building and Improvements | 859 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandSevenHundredAndOneCommerceDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,270 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandSevenHundredAndOneCommerceDriveMember |  |  |
Land | 164 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandSevenHundredAndOneCommerceDriveMember |  |  |
Building and improvements | 2,106 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandSevenHundredAndOneCommerceDriveMember |  |  |
Total | 2,270 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandSevenHundredAndOneCommerceDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,403 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandSevenHundredAndOneCommerceDriveMember |  |  |
2780 Commerce Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Middletown, PA |  |  |
Encumbrances | 1,648 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandSevenHundredAndEightyCommerceDriveMember |  |  |
Initial Cost of Land | 113 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandSevenHundredAndEightyCommerceDriveMember |  |  |
Building and Improvements | 743 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandSevenHundredAndEightyCommerceDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,130 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandSevenHundredAndEightyCommerceDriveMember |  |  |
Land | 209 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandSevenHundredAndEightyCommerceDriveMember |  |  |
Building and improvements | 1,777 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandSevenHundredAndEightyCommerceDriveMember |  |  |
Total | 1,986 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandSevenHundredAndEightyCommerceDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,349 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandSevenHundredAndEightyCommerceDriveMember |  |  |
350 Old Silver Spring Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Mechanicsburg, PA |  |  |
Initial Cost of Land | 510 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredAndFiftyOldSilverSpringRoadMember |  |  |
Building and Improvements | 2,890 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredAndFiftyOldSilverSpringRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 7,043 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredAndFiftyOldSilverSpringRoadMember |  |  |
Land | 541 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredAndFiftyOldSilverSpringRoadMember |  |  |
Building and improvements | 9,902 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredAndFiftyOldSilverSpringRoadMember |  |  |
Total | 10,443 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredAndFiftyOldSilverSpringRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 3,975 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredAndFiftyOldSilverSpringRoadMember |  |  |
16522 Hunters Green Parkway [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Hagerstown, MD |  |  |
Encumbrances | 12,222 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixteenThousandAndFiveHundredAndTwentyTwoHuntersGreenParkwayMember |  |  |
Initial Cost of Land | 1,390 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixteenThousandAndFiveHundredAndTwentyTwoHuntersGreenParkwayMember |  |  |
Building and Improvements | 13,104 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixteenThousandAndFiveHundredAndTwentyTwoHuntersGreenParkwayMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 4,841 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixteenThousandAndFiveHundredAndTwentyTwoHuntersGreenParkwayMember |  |  |
Land | 1,863 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixteenThousandAndFiveHundredAndTwentyTwoHuntersGreenParkwayMember |  |  |
Building and improvements | 17,472 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixteenThousandAndFiveHundredAndTwentyTwoHuntersGreenParkwayMember |  |  |
Total | 19,335 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixteenThousandAndFiveHundredAndTwentyTwoHuntersGreenParkwayMember |  |  |
Accumulated depreciation 12/31/2012 | 4,732 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixteenThousandAndFiveHundredAndTwentyTwoHuntersGreenParkwayMember |  |  |
18212 Shawley Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Hagerstown, MD |  |  |
Encumbrances | 6,438 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EighteenThousandTwoHundredAndTwelveShawleyDriveMember |  |  |
Initial Cost of Land | 1,000 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EighteenThousandTwoHundredAndTwelveShawleyDriveMember |  |  |
Building and Improvements | 5,847 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EighteenThousandTwoHundredAndTwelveShawleyDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 910 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EighteenThousandTwoHundredAndTwelveShawleyDriveMember |  |  |
Land | 1,016 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EighteenThousandTwoHundredAndTwelveShawleyDriveMember |  |  |
Building and improvements | 6,741 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EighteenThousandTwoHundredAndTwelveShawleyDriveMember |  |  |
Total | 7,757 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EighteenThousandTwoHundredAndTwelveShawleyDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,683 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EighteenThousandTwoHundredAndTwelveShawleyDriveMember |  |  |
37 Valley View Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Jessup, PA |  |  |
Encumbrances | 2,954 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeSevenValleyViewDriveMember |  |  |
Initial Cost of Land | 542 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeSevenValleyViewDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 3,017 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeSevenValleyViewDriveMember |  |  |
Land | 532 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeSevenValleyViewDriveMember |  |  |
Building and improvements | 3,027 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeSevenValleyViewDriveMember |  |  |
Total | 3,559 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeSevenValleyViewDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 752 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeSevenValleyViewDriveMember |  |  |
301 Railroad Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Shiremanstown, PA |  |  |
Initial Cost of Land | 1,181 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredOneRailroadAvenueMember |  |  |
Building and Improvements | 4,447 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredOneRailroadAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 3,034 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredOneRailroadAvenueMember |  |  |
Land | 1,328 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredOneRailroadAvenueMember |  |  |
Building and improvements | 7,334 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredOneRailroadAvenueMember |  |  |
Total | 8,662 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredOneRailroadAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 3,078 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredOneRailroadAvenueMember |  |  |
431 Railroad Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Shiremanstown, PA |  |  |
Encumbrances | 8,297 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThirtyOneRailroadAvenueMember |  |  |
Initial Cost of Land | 1,293 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThirtyOneRailroadAvenueMember |  |  |
Building and Improvements | 7,164 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThirtyOneRailroadAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,666 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThirtyOneRailroadAvenueMember |  |  |
Land | 1,341 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThirtyOneRailroadAvenueMember |  |  |
Building and improvements | 8,782 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThirtyOneRailroadAvenueMember |  |  |
Total | 10,123 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThirtyOneRailroadAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 3,518 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThirtyOneRailroadAvenueMember |  |  |
6951 Allentown Blvd [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Harrisburg, PA |  |  |
Initial Cost of Land | 585 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixThousandNineHundredAndFiftyOneAllentownBlvdMember |  |  |
Building and Improvements | 3,176 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixThousandNineHundredAndFiftyOneAllentownBlvdMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 301 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixThousandNineHundredAndFiftyOneAllentownBlvdMember |  |  |
Land | 601 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixThousandNineHundredAndFiftyOneAllentownBlvdMember |  |  |
Building and improvements | 3,461 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixThousandNineHundredAndFiftyOneAllentownBlvdMember |  |  |
Total | 4,062 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixThousandNineHundredAndFiftyOneAllentownBlvdMember |  |  |
Accumulated depreciation 12/31/2012 | 1,181 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixThousandNineHundredAndFiftyOneAllentownBlvdMember |  |  |
320 Reliance Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Washington, PA |  |  |
Initial Cost of Land | 201 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoZeroRelianceRoadMember |  |  |
Building and Improvements | 1,819 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoZeroRelianceRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (282)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoZeroRelianceRoadMember |  |  |
Land | 178 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoZeroRelianceRoadMember |  |  |
Building and improvements | 1,560 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoZeroRelianceRoadMember |  |  |
Total | 1,738 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoZeroRelianceRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 734 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoZeroRelianceRoadMember |  |  |
1351 Eisenhower Blvd., Bldg 1 [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Harrisburg, PA |  |  |
Initial Cost of Land | 382 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandThreeHundredAndFiftyOneEisenhowerBlvdBldgOneMember |  |  |
Building and Improvements | 2,343 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandThreeHundredAndFiftyOneEisenhowerBlvdBldgOneMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (64)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandThreeHundredAndFiftyOneEisenhowerBlvdBldgOneMember |  |  |
Land | 387 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandThreeHundredAndFiftyOneEisenhowerBlvdBldgOneMember |  |  |
Building and improvements | 2,274 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandThreeHundredAndFiftyOneEisenhowerBlvdBldgOneMember |  |  |
Total | 2,661 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandThreeHundredAndFiftyOneEisenhowerBlvdBldgOneMember |  |  |
Accumulated depreciation 12/31/2012 | 721 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandThreeHundredAndFiftyOneEisenhowerBlvdBldgOneMember |  |  |
1351 Eisenhower Blvd., Bldg 2 [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Harrisburg, PA |  |  |
Initial Cost of Land | 436 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandThreeHundredAndFiftyOneEisenhowerBlvdBldgTwoMember |  |  |
Building and Improvements | 1,587 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandThreeHundredAndFiftyOneEisenhowerBlvdBldgTwoMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 43 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandThreeHundredAndFiftyOneEisenhowerBlvdBldgTwoMember |  |  |
Land | 443 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandThreeHundredAndFiftyOneEisenhowerBlvdBldgTwoMember |  |  |
Building and improvements | 1,623 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandThreeHundredAndFiftyOneEisenhowerBlvdBldgTwoMember |  |  |
Total | 2,066 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandThreeHundredAndFiftyOneEisenhowerBlvdBldgTwoMember |  |  |
Accumulated depreciation 12/31/2012 | 601 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandThreeHundredAndFiftyOneEisenhowerBlvdBldgTwoMember |  |  |
1490 Dennison Circle [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Carlisle, PA |  |  |
Initial Cost of Land | 1,500 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandFourHundredNinetyDennisonCircleMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 13,880 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandFourHundredNinetyDennisonCircleMember |  |  |
Land | 2,341 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandFourHundredNinetyDennisonCircleMember |  |  |
Building and improvements | 13,039 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandFourHundredNinetyDennisonCircleMember |  |  |
Total | 15,380 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandFourHundredNinetyDennisonCircleMember |  |  |
Accumulated depreciation 12/31/2012 | 2,722 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandFourHundredNinetyDennisonCircleMember |  |  |
298 First Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Gouldsboro, PA |  |  |
Initial Cost of Land | 7,022 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineEightFirstAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 57,272 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineEightFirstAvenueMember |  |  |
Land | 7,019 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineEightFirstAvenueMember |  |  |
Building and improvements | 57,275 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineEightFirstAvenueMember |  |  |
Total | 64,294 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineEightFirstAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 9,106 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineEightFirstAvenueMember |  |  |
225 Cross Farm Lane [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | York, PA |  |  |
Encumbrances | 17,214 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoHundredAndTwentyFiveCrossFarmLaneMember |  |  |
Initial Cost of Land | 4,718 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoHundredAndTwentyFiveCrossFarmLaneMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 23,163 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoHundredAndTwentyFiveCrossFarmLaneMember |  |  |
Land | 4,715 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoHundredAndTwentyFiveCrossFarmLaneMember |  |  |
Building and improvements | 23,166 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoHundredAndTwentyFiveCrossFarmLaneMember |  |  |
Total | 27,881 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoHundredAndTwentyFiveCrossFarmLaneMember |  |  |
Accumulated depreciation 12/31/2012 | 4,204 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoHundredAndTwentyFiveCrossFarmLaneMember |  |  |
105 Steamboat Blvd [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Manchester, PA |  |  |
Initial Cost of Land | 4,085 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneHundredAndFiveSteamboatBlvdMember |  |  |
Building and Improvements | 14,464 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneHundredAndFiveSteamboatBlvdMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneHundredAndFiveSteamboatBlvdMember |  |  |
Land | 4,070 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneHundredAndFiveSteamboatBlvdMember |  |  |
Building and improvements | 14,480 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneHundredAndFiveSteamboatBlvdMember |  |  |
Total | 18,550 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneHundredAndFiveSteamboatBlvdMember |  |  |
Accumulated depreciation 12/31/2012 | 1,700 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneHundredAndFiveSteamboatBlvdMember |  |  |
20 Leo Lane [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | York County, PA |  |  |
Initial Cost of Land | 6,884 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwentyLeoLaneMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 26,451 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwentyLeoLaneMember |  |  |
Land | 6,889 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwentyLeoLaneMember |  |  |
Building and improvements | 26,446 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwentyLeoLaneMember |  |  |
Total | 33,335 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwentyLeoLaneMember |  |  |
Accumulated depreciation 12/31/2012 | 717 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwentyLeoLaneMember |  |  |
720-730 Landwehr Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Northbrook, IL |  |  |
Initial Cost of Land | 521 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenHundredTwentyAndSevenHundredThirtyLandwehrRoadMember |  |  |
Building and Improvements | 2,982 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenHundredTwentyAndSevenHundredThirtyLandwehrRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 783 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenHundredTwentyAndSevenHundredThirtyLandwehrRoadMember |  |  |
Land | 521 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenHundredTwentyAndSevenHundredThirtyLandwehrRoadMember |  |  |
Building and improvements | 3,765 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenHundredTwentyAndSevenHundredThirtyLandwehrRoadMember |  |  |
Total | 4,286 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenHundredTwentyAndSevenHundredThirtyLandwehrRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 1,723 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenHundredTwentyAndSevenHundredThirtyLandwehrRoadMember |  |  |
1385 101st Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Lemont, IL |  |  |
Encumbrances | 4,244 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThirteenEightyFiveAndOneHundredOneStStreetMember |  |  |
Initial Cost of Land | 967 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThirteenEightyFiveAndOneHundredOneStStreetMember |  |  |
Building and Improvements | 5,554 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThirteenEightyFiveAndOneHundredOneStStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,727 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThirteenEightyFiveAndOneHundredOneStStreetMember |  |  |
Land | 968 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThirteenEightyFiveAndOneHundredOneStStreetMember |  |  |
Building and improvements | 7,280 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThirteenEightyFiveAndOneHundredOneStStreetMember |  |  |
Total | 8,248 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThirteenEightyFiveAndOneHundredOneStStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 3,386 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThirteenEightyFiveAndOneHundredOneStStreetMember |  |  |
6750 South Sayre Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Bedford Park, IL |  |  |
Initial Cost of Land | 224 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixThousandSevenHundredFiftySouthSayreAvenueMember |  |  |
Building and Improvements | 1,309 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixThousandSevenHundredFiftySouthSayreAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 470 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixThousandSevenHundredFiftySouthSayreAvenueMember |  |  |
Land | 224 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixThousandSevenHundredFiftySouthSayreAvenueMember |  |  |
Building and improvements | 1,779 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixThousandSevenHundredFiftySouthSayreAvenueMember |  |  |
Total | 2,003 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixThousandSevenHundredFiftySouthSayreAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 826 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixThousandSevenHundredFiftySouthSayreAvenueMember |  |  |
585 Slawin Court [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Mount Prospect, IL |  |  |
Initial Cost of Land | 611 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveHundredEightyFiveSlawinCourtMember |  |  |
Building and Improvements | 3,505 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveHundredEightyFiveSlawinCourtMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 596 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveHundredEightyFiveSlawinCourtMember |  |  |
Land | 525 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveHundredEightyFiveSlawinCourtMember |  |  |
Building and improvements | 4,187 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveHundredEightyFiveSlawinCourtMember |  |  |
Total | 4,712 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveHundredEightyFiveSlawinCourtMember |  |  |
Accumulated depreciation 12/31/2012 | 2,376 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveHundredEightyFiveSlawinCourtMember |  |  |
2300 Windsor Court [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Addison, IL |  |  |
Encumbrances | 3,470 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandThreeHundredWindsorCourtMember |  |  |
Initial Cost of Land | 688 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandThreeHundredWindsorCourtMember |  |  |
Building and Improvements | 3,943 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandThreeHundredWindsorCourtMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 989 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandThreeHundredWindsorCourtMember |  |  |
Land | 696 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandThreeHundredWindsorCourtMember |  |  |
Building and improvements | 4,924 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandThreeHundredWindsorCourtMember |  |  |
Total | 5,620 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandThreeHundredWindsorCourtMember |  |  |
Accumulated depreciation 12/31/2012 | 2,493 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandThreeHundredWindsorCourtMember |  |  |
305-311 Era Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Northbrook, IL |  |  |
Initial Cost of Land | 200 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredFiveAndThreeHundredElevenEraDriveMember |  |  |
Building and Improvements | 1,154 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredFiveAndThreeHundredElevenEraDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,150 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredFiveAndThreeHundredElevenEraDriveMember |  |  |
Land | 205 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredFiveAndThreeHundredElevenEraDriveMember |  |  |
Building and improvements | 2,299 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredFiveAndThreeHundredElevenEraDriveMember |  |  |
Total | 2,504 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredFiveAndThreeHundredElevenEraDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 832 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredFiveAndThreeHundredElevenEraDriveMember |  |  |
365 North Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Carol Stream, IL |  |  |
Encumbrances | 5,882 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredSixtyFiveNorthAvenueMember |  |  |
Initial Cost of Land | 1,042 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredSixtyFiveNorthAvenueMember |  |  |
Building and Improvements | 6,882 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredSixtyFiveNorthAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 2,719 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredSixtyFiveNorthAvenueMember |  |  |
Land | 1,073 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredSixtyFiveNorthAvenueMember |  |  |
Building and improvements | 9,570 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredSixtyFiveNorthAvenueMember |  |  |
Total | 10,643 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredSixtyFiveNorthAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 5,181 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredSixtyFiveNorthAvenueMember |  |  |
11241 Melrose Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Franklin Park, IL |  |  |
Initial Cost of Land | 332 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ElevenThousandTwoHundredFortyOneMelroseStreetMember |  |  |
Building and Improvements | 1,931 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ElevenThousandTwoHundredFortyOneMelroseStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 78 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ElevenThousandTwoHundredFortyOneMelroseStreetMember |  |  |
Land | 208 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ElevenThousandTwoHundredFortyOneMelroseStreetMember |  |  |
Building and improvements | 2,133 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ElevenThousandTwoHundredFortyOneMelroseStreetMember |  |  |
Total | 2,341 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ElevenThousandTwoHundredFortyOneMelroseStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 1,291 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ElevenThousandTwoHundredFortyOneMelroseStreetMember |  |  |
11939 South Central Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Alsip, IL |  |  |
Initial Cost of Land | 1,208 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ElevenThousandNineHundredThirtyNineSCentralAvenueMember |  |  |
Building and Improvements | 6,843 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ElevenThousandNineHundredThirtyNineSCentralAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 2,657 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ElevenThousandNineHundredThirtyNineSCentralAvenueMember |  |  |
Land | 1,305 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ElevenThousandNineHundredThirtyNineSCentralAvenueMember |  |  |
Building and improvements | 9,403 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ElevenThousandNineHundredThirtyNineSCentralAvenueMember |  |  |
Total | 10,708 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ElevenThousandNineHundredThirtyNineSCentralAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 3,942 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ElevenThousandNineHundredThirtyNineSCentralAvenueMember |  |  |
1010-50 Sesame Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Bensenville, IL |  |  |
Initial Cost of Land | 979 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandTenAndFiftySesameStreetMember |  |  |
Building and Improvements | 5,546 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandTenAndFiftySesameStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 3,720 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandTenAndFiftySesameStreetMember |  |  |
Land | 1,048 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandTenAndFiftySesameStreetMember |  |  |
Building and improvements | 9,197 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandTenAndFiftySesameStreetMember |  |  |
Total | 10,245 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandTenAndFiftySesameStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 3,223 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandTenAndFiftySesameStreetMember |  |  |
800 Business Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Mount Prospect, IL |  |  |
Initial Cost of Land | 631 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightHundredBusinessCenterDriveMember |  |  |
Building and Improvements | 3,493 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightHundredBusinessCenterDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 328 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightHundredBusinessCenterDriveMember |  |  |
Land | 666 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightHundredBusinessCenterDriveMember |  |  |
Building and improvements | 3,786 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightHundredBusinessCenterDriveMember |  |  |
Total | 4,452 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightHundredBusinessCenterDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,328 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightHundredBusinessCenterDriveMember |  |  |
580 Slawin Court [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Mount Prospect, IL |  |  |
Encumbrances | 781 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveHundredEightySlawinCourtMember |  |  |
Initial Cost of Land | 233 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveHundredEightySlawinCourtMember |  |  |
Building and Improvements | 1,292 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveHundredEightySlawinCourtMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (37)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveHundredEightySlawinCourtMember |  |  |
Land | 162 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveHundredEightySlawinCourtMember |  |  |
Building and improvements | 1,326 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveHundredEightySlawinCourtMember |  |  |
Total | 1,488 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveHundredEightySlawinCourtMember |  |  |
Accumulated depreciation 12/31/2012 | 551 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveHundredEightySlawinCourtMember |  |  |
1005 101st Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Lemont, IL |  |  |
Encumbrances | 6,131 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TenZeroFiveAndOneHundredOneStStreetMember |  |  |
Initial Cost of Land | 1,200 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TenZeroFiveAndOneHundredOneStStreetMember |  |  |
Building and Improvements | 6,643 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TenZeroFiveAndOneHundredOneStStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,233 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TenZeroFiveAndOneHundredOneStStreetMember |  |  |
Land | 1,220 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TenZeroFiveAndOneHundredOneStStreetMember |  |  |
Building and improvements | 7,856 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TenZeroFiveAndOneHundredOneStStreetMember |  |  |
Total | 9,076 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TenZeroFiveAndOneHundredOneStStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 2,668 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TenZeroFiveAndOneHundredOneStStreetMember |  |  |
175 Wall Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Glendale Heights, IL |  |  |
Encumbrances | 1,395 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneHundredSeventyFiveWallStreetMember |  |  |
Initial Cost of Land | 427 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneHundredSeventyFiveWallStreetMember |  |  |
Building and Improvements | 2,363 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneHundredSeventyFiveWallStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 163 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneHundredSeventyFiveWallStreetMember |  |  |
Land | 433 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneHundredSeventyFiveWallStreetMember |  |  |
Building and improvements | 2,520 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneHundredSeventyFiveWallStreetMember |  |  |
Total | 2,953 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneHundredSeventyFiveWallStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 869 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneHundredSeventyFiveWallStreetMember |  |  |
800-820 Thorndale Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Bensenville, IL |  |  |
Initial Cost of Land | 751 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightHundredAndEightHundredTwentyThorndaleAvenueMember |  |  |
Building and Improvements | 4,159 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightHundredAndEightHundredTwentyThorndaleAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 812 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightHundredAndEightHundredTwentyThorndaleAvenueMember |  |  |
Land | 761 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightHundredAndEightHundredTwentyThorndaleAvenueMember |  |  |
Building and improvements | 4,961 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightHundredAndEightHundredTwentyThorndaleAvenueMember |  |  |
Total | 5,722 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightHundredAndEightHundredTwentyThorndaleAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 1,476 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightHundredAndEightHundredTwentyThorndaleAvenueMember |  |  |
251 Airport Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | North Aurora, IL |  |  |
Encumbrances | 4,998 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoHundredFiftyOneAirportRoadMember |  |  |
Initial Cost of Land | 983 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoHundredFiftyOneAirportRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 6,697 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoHundredFiftyOneAirportRoadMember |  |  |
Land | 983 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoHundredFiftyOneAirportRoadMember |  |  |
Building and improvements | 6,697 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoHundredFiftyOneAirportRoadMember |  |  |
Total | 7,680 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoHundredFiftyOneAirportRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 2,211 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoHundredFiftyOneAirportRoadMember |  |  |
1661 Feehanville Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Mount Prospect, IL |  |  |
Initial Cost of Land | 985 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandSixHundredSixtyOneFeehanvilleDriveMember |  |  |
Building and Improvements | 5,455 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandSixHundredSixtyOneFeehanvilleDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 3,252 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandSixHundredSixtyOneFeehanvilleDriveMember |  |  |
Land | 1,044 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandSixHundredSixtyOneFeehanvilleDriveMember |  |  |
Building and improvements | 8,648 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandSixHundredSixtyOneFeehanvilleDriveMember |  |  |
Total | 9,692 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandSixHundredSixtyOneFeehanvilleDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 2,968 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandSixHundredSixtyOneFeehanvilleDriveMember |  |  |
400 Crossroads Pkwy [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Bolingbrook, IL |  |  |
Encumbrances | 5,429 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredCrossroadsPkwyMember |  |  |
Initial Cost of Land | 1,178 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredCrossroadsPkwyMember |  |  |
Building and Improvements | 9,453 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredCrossroadsPkwyMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 808 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredCrossroadsPkwyMember |  |  |
Land | 1,181 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredCrossroadsPkwyMember |  |  |
Building and improvements | 10,258 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredCrossroadsPkwyMember |  |  |
Total | 11,439 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredCrossroadsPkwyMember |  |  |
Accumulated depreciation 12/31/2012 | 3,105 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredCrossroadsPkwyMember |  |  |
7609 W. Industrial Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Forest Park, IL |  |  |
Initial Cost of Land | 1,207 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandSixHundredNineWIndustrialDriveMember |  |  |
Building and Improvements | 2,343 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandSixHundredNineWIndustrialDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 122 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandSixHundredNineWIndustrialDriveMember |  |  |
Land | 1,213 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandSixHundredNineWIndustrialDriveMember |  |  |
Building and improvements | 2,459 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandSixHundredNineWIndustrialDriveMember |  |  |
Total | 3,672 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandSixHundredNineWIndustrialDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,082 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandSixHundredNineWIndustrialDriveMember |  |  |
7801 W. Industrial Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Forest Park, IL |  |  |
Initial Cost of Land | 1,215 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandEightHundredOneWIndustrialDriveMember |  |  |
Building and Improvements | 3,020 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandEightHundredOneWIndustrialDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 476 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandEightHundredOneWIndustrialDriveMember |  |  |
Land | 1,220 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandEightHundredOneWIndustrialDriveMember |  |  |
Building and improvements | 3,491 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandEightHundredOneWIndustrialDriveMember |  |  |
Total | 4,711 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandEightHundredOneWIndustrialDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,656 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandEightHundredOneWIndustrialDriveMember |  |  |
825 E. 26th Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | LaGrange, IL |  |  |
Initial Cost of Land | 1,547 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightHundredTwentyFiveETwentySixThStreetMember |  |  |
Building and Improvements | 2,078 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightHundredTwentyFiveETwentySixThStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 2,474 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightHundredTwentyFiveETwentySixThStreetMember |  |  |
Land | 1,617 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightHundredTwentyFiveETwentySixThStreetMember |  |  |
Building and improvements | 4,482 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightHundredTwentyFiveETwentySixThStreetMember |  |  |
Total | 6,099 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightHundredTwentyFiveETwentySixThStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 2,185 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightHundredTwentyFiveETwentySixThStreetMember |  |  |
725 Kimberly Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Carol Stream, IL |  |  |
Initial Cost of Land | 793 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenHundredTwentyFiveKimberlyDriveMember |  |  |
Building and Improvements | 1,395 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenHundredTwentyFiveKimberlyDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 223 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenHundredTwentyFiveKimberlyDriveMember |  |  |
Land | 801 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenHundredTwentyFiveKimberlyDriveMember |  |  |
Building and improvements | 1,610 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenHundredTwentyFiveKimberlyDriveMember |  |  |
Total | 2,411 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenHundredTwentyFiveKimberlyDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 580 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenHundredTwentyFiveKimberlyDriveMember |  |  |
17001 S. Vincennes [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Thornton, IL |  |  |
Initial Cost of Land | 497 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SeventeenThousandOneSVincennesMember |  |  |
Building and Improvements | 504 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SeventeenThousandOneSVincennesMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 37 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SeventeenThousandOneSVincennesMember |  |  |
Land | 513 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SeventeenThousandOneSVincennesMember |  |  |
Building and improvements | 525 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SeventeenThousandOneSVincennesMember |  |  |
Total | 1,038 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SeventeenThousandOneSVincennesMember |  |  |
Accumulated depreciation 12/31/2012 | 373 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SeventeenThousandOneSVincennesMember |  |  |
1111 Davis Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Elgin, IL |  |  |
Encumbrances | 2,387 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandOneHundredElevenDavisRoadMember |  |  |
Initial Cost of Land | 998 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandOneHundredElevenDavisRoadMember |  |  |
Building and Improvements | 1,859 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandOneHundredElevenDavisRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 601 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandOneHundredElevenDavisRoadMember |  |  |
Land | 1,046 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandOneHundredElevenDavisRoadMember |  |  |
Building and improvements | 2,412 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandOneHundredElevenDavisRoadMember |  |  |
Total | 3,458 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandOneHundredElevenDavisRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 1,481 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandOneHundredElevenDavisRoadMember |  |  |
2900 W. 166th Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Markham, IL |  |  |
Initial Cost of Land | 1,132 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandNineHundredWOneHundredSixtySixThStreetMember |  |  |
Building and Improvements | 4,293 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandNineHundredWOneHundredSixtySixThStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (881)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandNineHundredWOneHundredSixtySixThStreetMember |  |  |
Land | 1,134 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandNineHundredWOneHundredSixtySixThStreetMember |  |  |
Building and improvements | 3,410 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandNineHundredWOneHundredSixtySixThStreetMember |  |  |
Total | 4,544 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandNineHundredWOneHundredSixtySixThStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 806 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThousandNineHundredWOneHundredSixtySixThStreetMember |  |  |
4100 Rock Creek Blvd [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Joliet, IL |  |  |
Initial Cost of Land | 4,476 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandOneHundredRockCreekBlvdMember |  |  |
Building and Improvements | 16,061 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandOneHundredRockCreekBlvdMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 479 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandOneHundredRockCreekBlvdMember |  |  |
Land | 4,476 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandOneHundredRockCreekBlvdMember |  |  |
Building and improvements | 16,540 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandOneHundredRockCreekBlvdMember |  |  |
Total | 21,016 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandOneHundredRockCreekBlvdMember |  |  |
Accumulated depreciation 12/31/2012 | 1,043 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandOneHundredRockCreekBlvdMember |  |  |
555 W. Algonquin Rd [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Arlington Heights, IL |  |  |
Encumbrances | 2,021 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveHundredFiftyFiveWAlgonquinRdMember |  |  |
Initial Cost of Land | 574 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveHundredFiftyFiveWAlgonquinRdMember |  |  |
Building and Improvements | 741 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveHundredFiftyFiveWAlgonquinRdMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,936 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveHundredFiftyFiveWAlgonquinRdMember |  |  |
Land | 579 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveHundredFiftyFiveWAlgonquinRdMember |  |  |
Building and improvements | 2,672 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveHundredFiftyFiveWAlgonquinRdMember |  |  |
Total | 3,251 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveHundredFiftyFiveWAlgonquinRdMember |  |  |
Accumulated depreciation 12/31/2012 | 703 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveHundredFiftyFiveWAlgonquinRdMember |  |  |
10100 58th Place [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Kenosha, WI |  |  |
Initial Cost of Land | 4,201 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TenThousandOneHundredFiftyEightThPlaceMember |  |  |
Building and Improvements | 17,604 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TenThousandOneHundredFiftyEightThPlaceMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,443 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TenThousandOneHundredFiftyEightThPlaceMember |  |  |
Land | 4,201 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TenThousandOneHundredFiftyEightThPlaceMember |  |  |
Building and improvements | 19,047 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TenThousandOneHundredFiftyEightThPlaceMember |  |  |
Total | 23,248 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TenThousandOneHundredFiftyEightThPlaceMember |  |  |
Accumulated depreciation 12/31/2012 | 1,417 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TenThousandOneHundredFiftyEightThPlaceMember |  |  |
401 Airport Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | North Aurora, IL |  |  |
Initial Cost of Land | 534 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredOneAirportRoadMember |  |  |
Building and Improvements | 1,957 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredOneAirportRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 0 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredOneAirportRoadMember |  |  |
Land | 534 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredOneAirportRoadMember |  |  |
Building and improvements | 1,957 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredOneAirportRoadMember |  |  |
Total | 2,491 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredOneAirportRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 54 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredOneAirportRoadMember |  |  |
7000 W. 60th Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Chicago, IL |  |  |
Initial Cost of Land | 609 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandWSixtyThStreetMember |  |  |
Building and Improvements | 932 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandWSixtyThStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 100 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandWSixtyThStreetMember |  |  |
Land | 667 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandWSixtyThStreetMember |  |  |
Building and improvements | 974 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandWSixtyThStreetMember |  |  |
Total | 1,641 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandWSixtyThStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 603 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandWSixtyThStreetMember |  |  |
1501 Oakton Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Elk Grove Village, IL |  |  |
Encumbrances | 7,391 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandFiveHundredOneOaktonStreetMember |  |  |
Initial Cost of Land | 3,369 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandFiveHundredOneOaktonStreetMember |  |  |
Building and Improvements | 6,121 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandFiveHundredOneOaktonStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 434 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandFiveHundredOneOaktonStreetMember |  |  |
Land | 3,482 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandFiveHundredOneOaktonStreetMember |  |  |
Building and improvements | 6,442 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandFiveHundredOneOaktonStreetMember |  |  |
Total | 9,924 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandFiveHundredOneOaktonStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 1,535 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandFiveHundredOneOaktonStreetMember |  |  |
16500 W. 103rd Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Woodridge, IL |  |  |
Encumbrances | 2,431 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixteenThousandFiveHundredWOneHundredThreeRdStreetMember |  |  |
Initial Cost of Land | 744 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixteenThousandFiveHundredWOneHundredThreeRdStreetMember |  |  |
Building and Improvements | 2,458 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixteenThousandFiveHundredWOneHundredThreeRdStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 366 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixteenThousandFiveHundredWOneHundredThreeRdStreetMember |  |  |
Land | 762 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixteenThousandFiveHundredWOneHundredThreeRdStreetMember |  |  |
Building and improvements | 2,806 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixteenThousandFiveHundredWOneHundredThreeRdStreetMember |  |  |
Total | 3,568 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixteenThousandFiveHundredWOneHundredThreeRdStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 878 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixteenThousandFiveHundredWOneHundredThreeRdStreetMember |  |  |
8505 50th Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Kenosha, WI |  |  |
Initial Cost of Land | 3,212 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightFiveZeroFiveFiftyThStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 32,953 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightFiveZeroFiveFiftyThStreetMember |  |  |
Land | 3,212 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightFiveZeroFiveFiftyThStreetMember |  |  |
Building and improvements | 32,953 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightFiveZeroFiveFiftyThStreetMember |  |  |
Total | 36,165 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightFiveZeroFiveFiftyThStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 4,850 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightFiveZeroFiveFiftyThStreetMember |  |  |
9900-9970 Princeton [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Cincinnati, OH |  |  |
Encumbrances | 3,643 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandNineHundredAndNineThousandNineHundredSeventyPrincetonMember |  |  |
Initial Cost of Land | 545 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandNineHundredAndNineThousandNineHundredSeventyPrincetonMember |  |  |
Building and Improvements | 3,088 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandNineHundredAndNineThousandNineHundredSeventyPrincetonMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,759 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandNineHundredAndNineThousandNineHundredSeventyPrincetonMember |  |  |
Land | 566 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandNineHundredAndNineThousandNineHundredSeventyPrincetonMember |  |  |
Building and improvements | 4,826 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandNineHundredAndNineThousandNineHundredSeventyPrincetonMember |  |  |
Total | 5,392 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandNineHundredAndNineThousandNineHundredSeventyPrincetonMember |  |  |
Accumulated depreciation 12/31/2012 | 2,083 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandNineHundredAndNineThousandNineHundredSeventyPrincetonMember |  |  |
4700-4750 Creek Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Blue Ash, OH |  |  |
Initial Cost of Land | 1,080 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandSevenHundredAndFourThousandSevenHundredFiftyCreekRoadMember |  |  |
Building and Improvements | 6,118 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandSevenHundredAndFourThousandSevenHundredFiftyCreekRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,346 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandSevenHundredAndFourThousandSevenHundredFiftyCreekRoadMember |  |  |
Land | 1,109 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandSevenHundredAndFourThousandSevenHundredFiftyCreekRoadMember |  |  |
Building and improvements | 7,435 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandSevenHundredAndFourThousandSevenHundredFiftyCreekRoadMember |  |  |
Total | 8,544 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandSevenHundredAndFourThousandSevenHundredFiftyCreekRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 3,273 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandSevenHundredAndFourThousandSevenHundredFiftyCreekRoadMember |  |  |
4436 Mulhauser Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Hamilton, OH |  |  |
Encumbrances | 3,707 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandFourHundredThirtySixMulhauserRoadMember |  |  |
Initial Cost of Land | 630 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandFourHundredThirtySixMulhauserRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 5,375 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandFourHundredThirtySixMulhauserRoadMember |  |  |
Land | 630 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandFourHundredThirtySixMulhauserRoadMember |  |  |
Building and improvements | 5,375 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandFourHundredThirtySixMulhauserRoadMember |  |  |
Total | 6,005 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandFourHundredThirtySixMulhauserRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 1,657 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandFourHundredThirtySixMulhauserRoadMember |  |  |
4438 Mulhauser Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Hamilton, OH |  |  |
Encumbrances | 4,581 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandFourHundredThirtyEightMulhauserRoadMember |  |  |
Initial Cost of Land | 779 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandFourHundredThirtyEightMulhauserRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 6,579 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandFourHundredThirtyEightMulhauserRoadMember |  |  |
Land | 779 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandFourHundredThirtyEightMulhauserRoadMember |  |  |
Building and improvements | 6,579 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandFourHundredThirtyEightMulhauserRoadMember |  |  |
Total | 7,358 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandFourHundredThirtyEightMulhauserRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 2,116 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandFourHundredThirtyEightMulhauserRoadMember |  |  |
420 Wards Corner Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Loveland, OH |  |  |
Initial Cost of Land | 600 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredTwentyWardsCornerRoadMember |  |  |
Building and Improvements | 1,083 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredTwentyWardsCornerRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 757 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredTwentyWardsCornerRoadMember |  |  |
Land | 606 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredTwentyWardsCornerRoadMember |  |  |
Building and improvements | 1,834 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredTwentyWardsCornerRoadMember |  |  |
Total | 2,440 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredTwentyWardsCornerRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 586 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredTwentyWardsCornerRoadMember |  |  |
422 Wards Corner Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Loveland, OH |  |  |
Initial Cost of Land | 600 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredTwentyTwoWardsCornerRoadMember |  |  |
Building and Improvements | 1,811 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredTwentyTwoWardsCornerRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 35 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredTwentyTwoWardsCornerRoadMember |  |  |
Land | 592 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredTwentyTwoWardsCornerRoadMember |  |  |
Building and improvements | 1,854 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredTwentyTwoWardsCornerRoadMember |  |  |
Total | 2,446 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredTwentyTwoWardsCornerRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 586 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredTwentyTwoWardsCornerRoadMember |  |  |
4663 Dues Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Westchester, OH |  |  |
Initial Cost of Land | 858 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandSixHundredSixtyThreeDuesDriveMember |  |  |
Building and Improvements | 2,273 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandSixHundredSixtyThreeDuesDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 620 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandSixHundredSixtyThreeDuesDriveMember |  |  |
Land | 875 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandSixHundredSixtyThreeDuesDriveMember |  |  |
Building and improvements | 2,876 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandSixHundredSixtyThreeDuesDriveMember |  |  |
Total | 3,751 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandSixHundredSixtyThreeDuesDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 2,393 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandSixHundredSixtyThreeDuesDriveMember |  |  |
9345 Princeton-Glendale [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Westchester, OH |  |  |
Encumbrances | 1,530 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandThreeHundredFortyFivePrincetonGlendaleMember |  |  |
Initial Cost of Land | 818 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandThreeHundredFortyFivePrincetonGlendaleMember |  |  |
Building and Improvements | 1,648 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandThreeHundredFortyFivePrincetonGlendaleMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 380 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandThreeHundredFortyFivePrincetonGlendaleMember |  |  |
Land | 840 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandThreeHundredFortyFivePrincetonGlendaleMember |  |  |
Building and improvements | 2,006 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandThreeHundredFortyFivePrincetonGlendaleMember |  |  |
Total | 2,846 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandThreeHundredFortyFivePrincetonGlendaleMember |  |  |
Accumulated depreciation 12/31/2012 | 1,098 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandThreeHundredFortyFivePrincetonGlendaleMember |  |  |
9525 Glades Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Westchester, OH |  |  |
Initial Cost of Land | 347 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandFiveHundredTwentyFiveGladesDriveMember |  |  |
Building and Improvements | 1,323 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandFiveHundredTwentyFiveGladesDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 115 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandFiveHundredTwentyFiveGladesDriveMember |  |  |
Land | 355 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandFiveHundredTwentyFiveGladesDriveMember |  |  |
Building and improvements | 1,430 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandFiveHundredTwentyFiveGladesDriveMember |  |  |
Total | 1,785 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandFiveHundredTwentyFiveGladesDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 585 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandFiveHundredTwentyFiveGladesDriveMember |  |  |
9776-9876 Windisch Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Westchester, OH |  |  |
Initial Cost of Land | 392 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandSevenHundredSeventyFourAndNineThousandSevenHundredNinetyTwoWindischRoadMember |  |  |
Building and Improvements | 1,744 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandSevenHundredSeventyFourAndNineThousandSevenHundredNinetyTwoWindischRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 78 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandSevenHundredSeventyFourAndNineThousandSevenHundredNinetyTwoWindischRoadMember |  |  |
Land | 394 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandSevenHundredSeventyFourAndNineThousandSevenHundredNinetyTwoWindischRoadMember |  |  |
Building and improvements | 1,820 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandSevenHundredSeventyFourAndNineThousandSevenHundredNinetyTwoWindischRoadMember |  |  |
Total | 2,214 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandSevenHundredSeventyFourAndNineThousandSevenHundredNinetyTwoWindischRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 566 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandSevenHundredSeventyFourAndNineThousandSevenHundredNinetyTwoWindischRoadMember |  |  |
9808-9830 Windisch Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Westchester, OH |  |  |
Initial Cost of Land | 395 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandEightHundredEightAndNineThousandEightHundredThirtyWindischRoadMember |  |  |
Building and Improvements | 2,541 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandEightHundredEightAndNineThousandEightHundredThirtyWindischRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 85 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandEightHundredEightAndNineThousandEightHundredThirtyWindischRoadMember |  |  |
Land | 397 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandEightHundredEightAndNineThousandEightHundredThirtyWindischRoadMember |  |  |
Building and improvements | 2,624 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandEightHundredEightAndNineThousandEightHundredThirtyWindischRoadMember |  |  |
Total | 3,021 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandEightHundredEightAndNineThousandEightHundredThirtyWindischRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 617 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandEightHundredEightAndNineThousandEightHundredThirtyWindischRoadMember |  |  |
9842-9862 Windisch Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Westchester, OH |  |  |
Initial Cost of Land | 506 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandEightHundredFortyTwoAndNineThousandEightHundredSixtyTwoWindischRoadMember |  |  |
Building and Improvements | 3,148 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandEightHundredFortyTwoAndNineThousandEightHundredSixtyTwoWindischRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 102 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandEightHundredFortyTwoAndNineThousandEightHundredSixtyTwoWindischRoadMember |  |  |
Land | 508 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandEightHundredFortyTwoAndNineThousandEightHundredSixtyTwoWindischRoadMember |  |  |
Building and improvements | 3,248 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandEightHundredFortyTwoAndNineThousandEightHundredSixtyTwoWindischRoadMember |  |  |
Total | 3,756 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandEightHundredFortyTwoAndNineThousandEightHundredSixtyTwoWindischRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 796 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThousandEightHundredFortyTwoAndNineThousandEightHundredSixtyTwoWindischRoadMember |  |  |
9872-9898 Windisch Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Westchester, OH |  |  |
Initial Cost of Land | 546 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightSevenTwoToNineEightNineEightWindischRoadMember |  |  |
Building and Improvements | 3,039 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightSevenTwoToNineEightNineEightWindischRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 159 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightSevenTwoToNineEightNineEightWindischRoadMember |  |  |
Land | 548 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightSevenTwoToNineEightNineEightWindischRoadMember |  |  |
Building and improvements | 3,196 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightSevenTwoToNineEightNineEightWindischRoadMember |  |  |
Total | 3,744 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightSevenTwoToNineEightNineEightWindischRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 812 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightSevenTwoToNineEightNineEightWindischRoadMember |  |  |
9902-9922 Windisch Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Westchester, OH |  |  |
Initial Cost of Land | 623 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineNineZeroTwoToNineNineTwoTwoWindischRoadMember |  |  |
Building and Improvements | 4,003 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineNineZeroTwoToNineNineTwoTwoWindischRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 729 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineNineZeroTwoToNineNineTwoTwoWindischRoadMember |  |  |
Land | 627 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineNineZeroTwoToNineNineTwoTwoWindischRoadMember |  |  |
Building and improvements | 4,728 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineNineZeroTwoToNineNineTwoTwoWindischRoadMember |  |  |
Total | 5,355 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineNineZeroTwoToNineNineTwoTwoWindischRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 1,503 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineNineZeroTwoToNineNineTwoTwoWindischRoadMember |  |  |
30311 Emerald Valley Parkway [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Glenwillow, OH |  |  |
Encumbrances | 8,914 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroThreeOneOneEmeraldValleyParkwayMember |  |  |
Initial Cost of Land | 681 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroThreeOneOneEmeraldValleyParkwayMember |  |  |
Building and Improvements | 11,838 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroThreeOneOneEmeraldValleyParkwayMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 845 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroThreeOneOneEmeraldValleyParkwayMember |  |  |
Land | 691 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroThreeOneOneEmeraldValleyParkwayMember |  |  |
Building and improvements | 12,673 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroThreeOneOneEmeraldValleyParkwayMember |  |  |
Total | 13,364 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroThreeOneOneEmeraldValleyParkwayMember |  |  |
Accumulated depreciation 12/31/2012 | 3,862 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroThreeOneOneEmeraldValleyParkwayMember |  |  |
30333 Emerald Valley Parkway [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Glenwillow, OH |  |  |
Encumbrances | 3,896 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroThreeThreeThreeEmeraldValleyPkwyMember |  |  |
Initial Cost of Land | 466 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroThreeThreeThreeEmeraldValleyPkwyMember |  |  |
Building and Improvements | 5,447 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroThreeThreeThreeEmeraldValleyPkwyMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 54 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroThreeThreeThreeEmeraldValleyPkwyMember |  |  |
Land | 475 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroThreeThreeThreeEmeraldValleyPkwyMember |  |  |
Building and improvements | 5,492 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroThreeThreeThreeEmeraldValleyPkwyMember |  |  |
Total | 5,967 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroThreeThreeThreeEmeraldValleyPkwyMember |  |  |
Accumulated depreciation 12/31/2012 | 1,876 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroThreeThreeThreeEmeraldValleyPkwyMember |  |  |
7800 Cochran Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Glenwillow, OH |  |  |
Encumbrances | 3,897 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenEightZeroZeroCochranRoadMember |  |  |
Initial Cost of Land | 972 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenEightZeroZeroCochranRoadMember |  |  |
Building and Improvements | 7,033 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenEightZeroZeroCochranRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 243 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenEightZeroZeroCochranRoadMember |  |  |
Land | 991 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenEightZeroZeroCochranRoadMember |  |  |
Building and improvements | 7,257 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenEightZeroZeroCochranRoadMember |  |  |
Total | 8,248 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenEightZeroZeroCochranRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 2,123 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenEightZeroZeroCochranRoadMember |  |  |
7900 Cochran Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Glenwillow, OH |  |  |
Encumbrances | 4,794 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenNineZeroZeroCochranRoadMember |  |  |
Initial Cost of Land | 775 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenNineZeroZeroCochranRoadMember |  |  |
Building and Improvements | 6,244 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenNineZeroZeroCochranRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 237 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenNineZeroZeroCochranRoadMember |  |  |
Land | 792 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenNineZeroZeroCochranRoadMember |  |  |
Building and improvements | 6,464 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenNineZeroZeroCochranRoadMember |  |  |
Total | 7,256 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenNineZeroZeroCochranRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 1,900 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenNineZeroZeroCochranRoadMember |  |  |
7905 Cochran Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Glenwillow, OH |  |  |
Initial Cost of Land | 920 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenNineZeroFiveCochranRoadMember |  |  |
Building and Improvements | 6,174 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenNineZeroFiveCochranRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 691 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenNineZeroFiveCochranRoadMember |  |  |
Land | 921 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenNineZeroFiveCochranRoadMember |  |  |
Building and improvements | 6,864 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenNineZeroFiveCochranRoadMember |  |  |
Total | 7,785 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenNineZeroFiveCochranRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 2,210 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenNineZeroFiveCochranRoadMember |  |  |
30600 Carter Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Solon, OH |  |  |
Initial Cost of Land | 989 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroSixZeroZeroCarterStreetMember |  |  |
Building and Improvements | 3,042 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroSixZeroZeroCarterStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 881 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroSixZeroZeroCarterStreetMember |  |  |
Land | 1,022 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroSixZeroZeroCarterStreetMember |  |  |
Building and improvements | 3,890 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroSixZeroZeroCarterStreetMember |  |  |
Total | 4,912 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroSixZeroZeroCarterStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 2,487 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroSixZeroZeroCarterStreetMember |  |  |
8181 Darrow Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Twinsburg, OH |  |  |
Encumbrances | 6,983 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightOneEightOneDarrowRoadMember |  |  |
Initial Cost of Land | 2,478 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightOneEightOneDarrowRoadMember |  |  |
Building and Improvements | 6,791 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightOneEightOneDarrowRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 2,040 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightOneEightOneDarrowRoadMember |  |  |
Land | 2,496 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightOneEightOneDarrowRoadMember |  |  |
Building and improvements | 8,813 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightOneEightOneDarrowRoadMember |  |  |
Total | 11,309 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightOneEightOneDarrowRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 3,351 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightOneEightOneDarrowRoadMember |  |  |
4785 Elati [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Denver, CO |  |  |
Initial Cost of Land | 173 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenEightFiveElatiMember |  |  |
Building and Improvements | 981 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenEightFiveElatiMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 205 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenEightFiveElatiMember |  |  |
Land | 175 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenEightFiveElatiMember |  |  |
Building and improvements | 1,184 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenEightFiveElatiMember |  |  |
Total | 1,359 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenEightFiveElatiMember |  |  |
Accumulated depreciation 12/31/2012 | 481 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenEightFiveElatiMember |  |  |
4770 Fox Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Denver, CO |  |  |
Initial Cost of Land | 132 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenSevenZeroFoxStreetMember |  |  |
Building and Improvements | 750 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenSevenZeroFoxStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 332 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenSevenZeroFoxStreetMember |  |  |
Land | 134 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenSevenZeroFoxStreetMember |  |  |
Building and improvements | 1,080 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenSevenZeroFoxStreetMember |  |  |
Total | 1,214 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenSevenZeroFoxStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 423 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenSevenZeroFoxStreetMember |  |  |
3851-3871 Revere [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Denver, CO |  |  |
Encumbrances |  | 1,271 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeEightFiveOneThreeEightSevenOneRevereMember |  |
Initial Cost of Land | 361 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeEightFiveOneThreeEightSevenOneRevereMember |  |  |
Building and Improvements | 2,047 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeEightFiveOneThreeEightSevenOneRevereMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 363 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeEightFiveOneThreeEightSevenOneRevereMember |  |  |
Land | 368 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeEightFiveOneThreeEightSevenOneRevereMember |  |  |
Building and improvements | 2,403 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeEightFiveOneThreeEightSevenOneRevereMember |  |  |
Total | 2,771 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeEightFiveOneThreeEightSevenOneRevereMember |  |  |
Accumulated depreciation 12/31/2012 | 983 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeEightFiveOneThreeEightSevenOneRevereMember |  |  |
4570 Ivy Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Denver, CO |  |  |
Initial Cost of Land | 219 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveSevenZeroIvyStreetMember |  |  |
Building and Improvements | 1,239 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveSevenZeroIvyStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 279 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveSevenZeroIvyStreetMember |  |  |
Land | 220 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveSevenZeroIvyStreetMember |  |  |
Building and improvements | 1,517 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveSevenZeroIvyStreetMember |  |  |
Total | 1,737 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveSevenZeroIvyStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 649 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveSevenZeroIvyStreetMember |  |  |
5855 Stapleton Drive North [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Denver, CO |  |  |
Initial Cost of Land | 288 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveEightFiveFiveStapletonDriveNorthMember |  |  |
Building and Improvements | 1,630 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveEightFiveFiveStapletonDriveNorthMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 249 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveEightFiveFiveStapletonDriveNorthMember |  |  |
Land | 290 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveEightFiveFiveStapletonDriveNorthMember |  |  |
Building and improvements | 1,877 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveEightFiveFiveStapletonDriveNorthMember |  |  |
Total | 2,167 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveEightFiveFiveStapletonDriveNorthMember |  |  |
Accumulated depreciation 12/31/2012 | 780 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveEightFiveFiveStapletonDriveNorthMember |  |  |
5885 Stapleton Drive North [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Denver, CO |  |  |
Initial Cost of Land | 376 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveEightEightFiveStapletonDriveNorthMember |  |  |
Building and Improvements | 2,129 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveEightEightFiveStapletonDriveNorthMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 316 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveEightEightFiveStapletonDriveNorthMember |  |  |
Land | 380 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveEightEightFiveStapletonDriveNorthMember |  |  |
Building and improvements | 2,441 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveEightEightFiveStapletonDriveNorthMember |  |  |
Total | 2,821 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveEightEightFiveStapletonDriveNorthMember |  |  |
Accumulated depreciation 12/31/2012 | 987 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveEightEightFiveStapletonDriveNorthMember |  |  |
5977 North Broadway [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Denver, CO |  |  |
Encumbrances |  | 1,415 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveNineSevenSevenNorthBroadwayMember |  |
Initial Cost of Land | 268 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveNineSevenSevenNorthBroadwayMember |  |  |
Building and Improvements | 1,518 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveNineSevenSevenNorthBroadwayMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 506 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveNineSevenSevenNorthBroadwayMember |  |  |
Land | 271 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveNineSevenSevenNorthBroadwayMember |  |  |
Building and improvements | 2,021 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveNineSevenSevenNorthBroadwayMember |  |  |
Total | 2,292 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveNineSevenSevenNorthBroadwayMember |  |  |
Accumulated depreciation 12/31/2012 | 794 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveNineSevenSevenNorthBroadwayMember |  |  |
5952-5978 North Broadway [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Denver, CO |  |  |
Encumbrances |  | 2,262 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveNineFiveTwoFiveNineSevenEightNorthBroadwayMember |  |
Initial Cost of Land | 414 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveNineFiveTwoFiveNineSevenEightNorthBroadwayMember |  |  |
Building and Improvements | 2,346 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveNineFiveTwoFiveNineSevenEightNorthBroadwayMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 904 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveNineFiveTwoFiveNineSevenEightNorthBroadwayMember |  |  |
Land | 422 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveNineFiveTwoFiveNineSevenEightNorthBroadwayMember |  |  |
Building and improvements | 3,242 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveNineFiveTwoFiveNineSevenEightNorthBroadwayMember |  |  |
Total | 3,664 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveNineFiveTwoFiveNineSevenEightNorthBroadwayMember |  |  |
Accumulated depreciation 12/31/2012 | 1,439 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveNineFiveTwoFiveNineSevenEightNorthBroadwayMember |  |  |
4721 Ironton Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Denver, CO |  |  |
Initial Cost of Land | 232 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenTwoOneIrontonStreetMember |  |  |
Building and Improvements | 1,313 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenTwoOneIrontonStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 319 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenTwoOneIrontonStreetMember |  |  |
Land | 236 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenTwoOneIrontonStreetMember |  |  |
Building and improvements | 1,628 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenTwoOneIrontonStreetMember |  |  |
Total | 1,864 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenTwoOneIrontonStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 665 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenTwoOneIrontonStreetMember |  |  |
7003 E 47th Ave Drive [Member ] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Denver, CO |  |  |
Initial Cost of Land | 441 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenZeroZeroThreeFourSeventhAveDriveMember |  |  |
Building and Improvements | 2,689 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenZeroZeroThreeFourSeventhAveDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 58 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenZeroZeroThreeFourSeventhAveDriveMember |  |  |
Land | 441 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenZeroZeroThreeFourSeventhAveDriveMember |  |  |
Building and improvements | 2,747 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenZeroZeroThreeFourSeventhAveDriveMember |  |  |
Total | 3,188 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenZeroZeroThreeFourSeventhAveDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,189 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenZeroZeroThreeFourSeventhAveDriveMember |  |  |
9500 West 49th Street - A [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Wheatridge, CO |  |  |
Initial Cost of Land | 283 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineFiveZeroZeroWestFourNinthStreetMember |  |  |
Building and Improvements | 1,625 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineFiveZeroZeroWestFourNinthStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 120 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineFiveZeroZeroWestFourNinthStreetMember |  |  |
Land | 287 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineFiveZeroZeroWestFourNinthStreetMember |  |  |
Building and improvements | 1,741 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineFiveZeroZeroWestFourNinthStreetMember |  |  |
Total | 2,028 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineFiveZeroZeroWestFourNinthStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 775 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineFiveZeroZeroWestFourNinthStreetMember |  |  |
9500 West 49th Street - B [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Wheatridge, CO |  |  |
Initial Cost of Land | 225 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineFiveZeroZeroWestFourNinthStreetBMember |  |  |
Building and Improvements | 1,272 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineFiveZeroZeroWestFourNinthStreetBMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 200 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineFiveZeroZeroWestFourNinthStreetBMember |  |  |
Land | 227 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineFiveZeroZeroWestFourNinthStreetBMember |  |  |
Building and improvements | 1,470 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineFiveZeroZeroWestFourNinthStreetBMember |  |  |
Total | 1,697 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineFiveZeroZeroWestFourNinthStreetBMember |  |  |
Accumulated depreciation 12/31/2012 | 603 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineFiveZeroZeroWestFourNinthStreetBMember |  |  |
9500 West 49th Street - C [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Wheatridge, CO |  |  |
Initial Cost of Land | 600 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineFiveZeroZeroWestFourNinthStreetCMember |  |  |
Building and Improvements | 3,409 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineFiveZeroZeroWestFourNinthStreetCMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 163 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineFiveZeroZeroWestFourNinthStreetCMember |  |  |
Land | 601 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineFiveZeroZeroWestFourNinthStreetCMember |  |  |
Building and improvements | 3,571 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineFiveZeroZeroWestFourNinthStreetCMember |  |  |
Total | 4,172 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineFiveZeroZeroWestFourNinthStreetCMember |  |  |
Accumulated depreciation 12/31/2012 | 1,567 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineFiveZeroZeroWestFourNinthStreetCMember |  |  |
9500 West 49th Street - D [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Wheatridge, CO |  |  |
Initial Cost of Land | 246 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineFiveZeroZeroWestFourNinthStreetDMember |  |  |
Building and Improvements | 1,537 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineFiveZeroZeroWestFourNinthStreetDMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 487 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineFiveZeroZeroWestFourNinthStreetDMember |  |  |
Land | 247 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineFiveZeroZeroWestFourNinthStreetDMember |  |  |
Building and improvements | 2,023 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineFiveZeroZeroWestFourNinthStreetDMember |  |  |
Total | 2,270 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineFiveZeroZeroWestFourNinthStreetDMember |  |  |
Accumulated depreciation 12/31/2012 | 927 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineFiveZeroZeroWestFourNinthStreetDMember |  |  |
451-591 East 124th Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Littleton, CO |  |  |
Initial Cost of Land | 383 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveOneFiveNineOneEastOneTwoFourThAvenueMember |  |  |
Building and Improvements | 2,145 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveOneFiveNineOneEastOneTwoFourThAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 481 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveOneFiveNineOneEastOneTwoFourThAvenueMember |  |  |
Land | 383 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveOneFiveNineOneEastOneTwoFourThAvenueMember |  |  |
Building and improvements | 2,626 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveOneFiveNineOneEastOneTwoFourThAvenueMember |  |  |
Total | 3,009 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveOneFiveNineOneEastOneTwoFourThAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 1,096 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveOneFiveNineOneEastOneTwoFourThAvenueMember |  |  |
15000 West 6th Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Golden, CO |  |  |
Initial Cost of Land | 913 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveZeroZeroZeroWestSixThAvenueMember |  |  |
Building and Improvements | 5,174 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveZeroZeroZeroWestSixThAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,147 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveZeroZeroZeroWestSixThAvenueMember |  |  |
Land | 918 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveZeroZeroZeroWestSixThAvenueMember |  |  |
Building and improvements | 6,316 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveZeroZeroZeroWestSixThAvenueMember |  |  |
Total | 7,234 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveZeroZeroZeroWestSixThAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 2,824 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveZeroZeroZeroWestSixThAvenueMember |  |  |
14998 West 6th Avenue Bldg E [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Golden, CO |  |  |
Initial Cost of Land | 565 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourNineNineEightWestSixThAvenueBldgEMember |  |  |
Building and Improvements | 3,199 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourNineNineEightWestSixThAvenueBldgEMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 371 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourNineNineEightWestSixThAvenueBldgEMember |  |  |
Land | 570 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourNineNineEightWestSixThAvenueBldgEMember |  |  |
Building and improvements | 3,565 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourNineNineEightWestSixThAvenueBldgEMember |  |  |
Total | 4,135 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourNineNineEightWestSixThAvenueBldgEMember |  |  |
Accumulated depreciation 12/31/2012 | 1,486 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourNineNineEightWestSixThAvenueBldgEMember |  |  |
14998 West 6 th Avenue Bldg F [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Englewood, CO |  |  |
Initial Cost of Land | 269 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourNineNineEightWestSixThAvenueBldgFMember |  |  |
Building and Improvements | 1,525 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourNineNineEightWestSixThAvenueBldgFMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 101 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourNineNineEightWestSixThAvenueBldgFMember |  |  |
Land | 273 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourNineNineEightWestSixThAvenueBldgFMember |  |  |
Building and improvements | 1,622 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourNineNineEightWestSixThAvenueBldgFMember |  |  |
Total | 1,895 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourNineNineEightWestSixThAvenueBldgFMember |  |  |
Accumulated depreciation 12/31/2012 | 698 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourNineNineEightWestSixThAvenueBldgFMember |  |  |
6547 South Racine Circle [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Englewood, CO |  |  |
Encumbrances |  | 2,703 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveFourSevenSouthRacineCircleMember |  |
Initial Cost of Land | 739 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveFourSevenSouthRacineCircleMember |  |  |
Building and Improvements | 4,241 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveFourSevenSouthRacineCircleMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 170 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveFourSevenSouthRacineCircleMember |  |  |
Land | 739 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveFourSevenSouthRacineCircleMember |  |  |
Building and improvements | 4,411 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveFourSevenSouthRacineCircleMember |  |  |
Total | 5,150 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveFourSevenSouthRacineCircleMember |  |  |
Accumulated depreciation 12/31/2012 | 1,868 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveFourSevenSouthRacineCircleMember |  |  |
11701 East 53rd Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Denver, CO |  |  |
Initial Cost of Land | 416 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneSevenZeroOneEastFiveThreeRdAvenueMember |  |  |
Building and Improvements | 2,355 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneSevenZeroOneEastFiveThreeRdAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 414 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneSevenZeroOneEastFiveThreeRdAvenueMember |  |  |
Land | 422 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneSevenZeroOneEastFiveThreeRdAvenueMember |  |  |
Building and improvements | 2,763 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneSevenZeroOneEastFiveThreeRdAvenueMember |  |  |
Total | 3,185 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneSevenZeroOneEastFiveThreeRdAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 1,145 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneSevenZeroOneEastFiveThreeRdAvenueMember |  |  |
5401 Oswego [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Denver, CO |  |  |
Initial Cost of Land | 273 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourOneZeroOswegoStreetMember |  |  |
Building and Improvements | 1,547 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourOneZeroOswegoStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 313 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourOneZeroOswegoStreetMember |  |  |
Land | 278 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourOneZeroOswegoStreetMember |  |  |
Building and improvements | 1,855 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourOneZeroOswegoStreetMember |  |  |
Total | 2,133 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourOneZeroOswegoStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 798 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourOneZeroOswegoStreetMember |  |  |
14818 West 6th Avenue Bldg A [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Golden, CO |  |  |
Initial Cost of Land | 468 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourEightOneEightWestSixThAvenueBldgAMember |  |  |
Building and Improvements | 2,799 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourEightOneEightWestSixThAvenueBldgAMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 278 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourEightOneEightWestSixThAvenueBldgAMember |  |  |
Land | 468 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourEightOneEightWestSixThAvenueBldgAMember |  |  |
Building and improvements | 3,077 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourEightOneEightWestSixThAvenueBldgAMember |  |  |
Total | 3,545 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourEightOneEightWestSixThAvenueBldgAMember |  |  |
Accumulated depreciation 12/31/2012 | 1,277 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourEightOneEightWestSixThAvenueBldgAMember |  |  |
14828 West 6th Avenue Bldg B [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Golden, CO |  |  |
Initial Cost of Land | 503 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourEightTwoEightWestSixthAvenueBldgMember |  |  |
Building and Improvements | 2,942 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourEightTwoEightWestSixthAvenueBldgMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 397 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourEightTwoEightWestSixthAvenueBldgMember |  |  |
Land | 503 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourEightTwoEightWestSixthAvenueBldgMember |  |  |
Building and improvements | 3,339 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourEightTwoEightWestSixthAvenueBldgMember |  |  |
Total | 3,842 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourEightTwoEightWestSixthAvenueBldgMember |  |  |
Accumulated depreciation 12/31/2012 | 1,442 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourEightTwoEightWestSixthAvenueBldgMember |  |  |
445 Bryant Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Denver, CO |  |  |
Encumbrances |  | 6,747 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredFortyFiveBryantStreetMember |  |
Initial Cost of Land | 1,829 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredFortyFiveBryantStreetMember |  |  |
Building and Improvements | 10,219 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredFortyFiveBryantStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 2,664 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredFortyFiveBryantStreetMember |  |  |
Land | 1,829 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredFortyFiveBryantStreetMember |  |  |
Building and improvements | 12,883 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredFortyFiveBryantStreetMember |  |  |
Total | 14,712 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredFortyFiveBryantStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 5,429 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredFortyFiveBryantStreetMember |  |  |
3811 Joliet [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Denver, CO |  |  |
Initial Cost of Land | 735 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThousandEightHundredElevenJolietMember |  |  |
Building and Improvements | 4,166 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThousandEightHundredElevenJolietMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 543 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThousandEightHundredElevenJolietMember |  |  |
Land | 752 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThousandEightHundredElevenJolietMember |  |  |
Building and improvements | 4,692 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThousandEightHundredElevenJolietMember |  |  |
Total | 5,444 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThousandEightHundredElevenJolietMember |  |  |
Accumulated depreciation 12/31/2012 | 1,926 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThousandEightHundredElevenJolietMember |  |  |
12055 E 49th Ave/4955 Peoria [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Denver, CO |  |  |
Initial Cost of Land | 298 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwelveThousandFiftyFiveEFortyNineThAveByFourThousandNineHundredFiftyFivePeoriaMember |  |  |
Building and Improvements | 1,688 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwelveThousandFiftyFiveEFortyNineThAveByFourThousandNineHundredFiftyFivePeoriaMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 529 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwelveThousandFiftyFiveEFortyNineThAveByFourThousandNineHundredFiftyFivePeoriaMember |  |  |
Land | 305 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwelveThousandFiftyFiveEFortyNineThAveByFourThousandNineHundredFiftyFivePeoriaMember |  |  |
Building and improvements | 2,210 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwelveThousandFiftyFiveEFortyNineThAveByFourThousandNineHundredFiftyFivePeoriaMember |  |  |
Total | 2,515 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwelveThousandFiftyFiveEFortyNineThAveByFourThousandNineHundredFiftyFivePeoriaMember |  |  |
Accumulated depreciation 12/31/2012 | 892 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwelveThousandFiftyFiveEFortyNineThAveByFourThousandNineHundredFiftyFivePeoriaMember |  |  |
4940 - 4950 Paris [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Denver, CO |  |  |
Initial Cost of Land | 152 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandNineHundredFortyAndFourThousandNineHundredFiftyParisMember |  |  |
Building and Improvements | 861 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandNineHundredFortyAndFourThousandNineHundredFiftyParisMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 285 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandNineHundredFortyAndFourThousandNineHundredFiftyParisMember |  |  |
Land | 156 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandNineHundredFortyAndFourThousandNineHundredFiftyParisMember |  |  |
Building and improvements | 1,142 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandNineHundredFortyAndFourThousandNineHundredFiftyParisMember |  |  |
Total | 1,298 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandNineHundredFortyAndFourThousandNineHundredFiftyParisMember |  |  |
Accumulated depreciation 12/31/2012 | 469 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandNineHundredFortyAndFourThousandNineHundredFiftyParisMember |  |  |
4970 Paris [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Denver, CO |  |  |
Initial Cost of Land | 95 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandNineHundredSeventyParisMember |  |  |
Building and Improvements | 537 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandNineHundredSeventyParisMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 101 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandNineHundredSeventyParisMember |  |  |
Land | 97 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandNineHundredSeventyParisMember |  |  |
Building and improvements | 636 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandNineHundredSeventyParisMember |  |  |
Total | 733 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandNineHundredSeventyParisMember |  |  |
Accumulated depreciation 12/31/2012 | 256 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandNineHundredSeventyParisMember |  |  |
7367 South Revere Parkway [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Englewood, CO |  |  |
Encumbrances |  | 3,151 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandThreeHundredSixtySevenSouthRevereParkwayMember |  |
Initial Cost of Land | 926 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandThreeHundredSixtySevenSouthRevereParkwayMember |  |  |
Building and Improvements | 5,124 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandThreeHundredSixtySevenSouthRevereParkwayMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 820 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandThreeHundredSixtySevenSouthRevereParkwayMember |  |  |
Land | 934 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandThreeHundredSixtySevenSouthRevereParkwayMember |  |  |
Building and improvements | 5,936 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandThreeHundredSixtySevenSouthRevereParkwayMember |  |  |
Total | 6,870 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandThreeHundredSixtySevenSouthRevereParkwayMember |  |  |
Accumulated depreciation 12/31/2012 | 2,420 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandThreeHundredSixtySevenSouthRevereParkwayMember |  |  |
8200 East Park Meadows Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Lone Tree, CO |  |  |
Initial Cost of Land | 1,297 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandTwoHundredEastParkMeadowsDriveMember |  |  |
Building and Improvements | 7,348 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandTwoHundredEastParkMeadowsDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,265 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandTwoHundredEastParkMeadowsDriveMember |  |  |
Land | 1,304 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandTwoHundredEastParkMeadowsDriveMember |  |  |
Building and improvements | 8,606 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandTwoHundredEastParkMeadowsDriveMember |  |  |
Total | 9,910 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandTwoHundredEastParkMeadowsDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 3,098 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandTwoHundredEastParkMeadowsDriveMember |  |  |
3250 Quentin Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Aurora, CO |  |  |
Initial Cost of Land | 1,220 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThousandTwoHundredFiftyQuentinMember |  |  |
Building and Improvements | 6,911 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThousandTwoHundredFiftyQuentinMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 782 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThousandTwoHundredFiftyQuentinMember |  |  |
Land | 1,230 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThousandTwoHundredFiftyQuentinMember |  |  |
Building and improvements | 7,683 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThousandTwoHundredFiftyQuentinMember |  |  |
Total | 8,913 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThousandTwoHundredFiftyQuentinMember |  |  |
Accumulated depreciation 12/31/2012 | 2,655 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThousandTwoHundredFiftyQuentinMember |  |  |
Highpoint Bus Ctr B [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Littleton, CO |  |  |
Initial Cost of Land | 739 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_HighpointBusCtrBMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 3,308 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_HighpointBusCtrBMember |  |  |
Land | 781 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_HighpointBusCtrBMember |  |  |
Building and improvements | 3,266 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_HighpointBusCtrBMember |  |  |
Total | 4,047 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_HighpointBusCtrBMember |  |  |
Accumulated depreciation 12/31/2012 | 971 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_HighpointBusCtrBMember |  |  |
1130 W. 124th Ave. [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Westminster, CO |  |  |
Initial Cost of Land | 441 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandOneHundredThirtyWOneHundredTwentyFourThAveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 3,289 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandOneHundredThirtyWOneHundredTwentyFourThAveMember |  |  |
Land | 441 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandOneHundredThirtyWOneHundredTwentyFourThAveMember |  |  |
Building and improvements | 3,289 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandOneHundredThirtyWOneHundredTwentyFourThAveMember |  |  |
Total | 3,730 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandOneHundredThirtyWOneHundredTwentyFourThAveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,241 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandOneHundredThirtyWOneHundredTwentyFourThAveMember |  |  |
1070 W. 124th Ave. [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Westminster, CO |  |  |
Initial Cost of Land | 374 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandSeventyWOneHundredTwentyFourThAveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 2,836 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandSeventyWOneHundredTwentyFourThAveMember |  |  |
Land | 374 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandSeventyWOneHundredTwentyFourThAveMember |  |  |
Building and improvements | 2,836 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandSeventyWOneHundredTwentyFourThAveMember |  |  |
Total | 3,210 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandSeventyWOneHundredTwentyFourThAveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,002 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandSeventyWOneHundredTwentyFourThAveMember |  |  |
1020 W. 124th Ave. [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Westminster, CO |  |  |
Initial Cost of Land | 374 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandTwentyWOneHundredTwentyFourThAveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 2,809 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandTwentyWOneHundredTwentyFourThAveMember |  |  |
Land | 374 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandTwentyWOneHundredTwentyFourThAveMember |  |  |
Building and improvements | 2,809 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandTwentyWOneHundredTwentyFourThAveMember |  |  |
Total | 3,183 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandTwentyWOneHundredTwentyFourThAveMember |  |  |
Accumulated depreciation 12/31/2012 | 949 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandTwentyWOneHundredTwentyFourThAveMember |  |  |
8810 W. 116th Circle [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Broomfield, CO |  |  |
Initial Cost of Land | 312 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandEightHundredTenWestOneHundredSixteenThStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,514 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandEightHundredTenWestOneHundredSixteenThStreetMember |  |  |
Land | 370 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandEightHundredTenWestOneHundredSixteenThStreetMember |  |  |
Building and improvements | 1,456 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandEightHundredTenWestOneHundredSixteenThStreetMember |  |  |
Total | 1,826 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandEightHundredTenWestOneHundredSixteenThStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 422 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandEightHundredTenWestOneHundredSixteenThStreetMember |  |  |
960 W. 124th Ave [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Westminster, CO |  |  |
Initial Cost of Land | 441 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineHundredSixtyWOneHundredTwentyFourThAveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 3,507 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineHundredSixtyWOneHundredTwentyFourThAveMember |  |  |
Land | 442 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineHundredSixtyWOneHundredTwentyFourThAveMember |  |  |
Building and improvements | 3,506 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineHundredSixtyWOneHundredTwentyFourThAveMember |  |  |
Total | 3,948 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineHundredSixtyWOneHundredTwentyFourThAveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,187 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineHundredSixtyWOneHundredTwentyFourThAveMember |  |  |
8820 W. 116th Circle [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Broomfield, CO |  |  |
Initial Cost of Land | 338 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandEightHundredTwentyWOneHundredSixteenThStreetMember |  |  |
Building and Improvements | 1,918 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandEightHundredTwentyWOneHundredSixteenThStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 321 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandEightHundredTwentyWOneHundredSixteenThStreetMember |  |  |
Land | 372 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandEightHundredTwentyWOneHundredSixteenThStreetMember |  |  |
Building and improvements | 2,205 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandEightHundredTwentyWOneHundredSixteenThStreetMember |  |  |
Total | 2,577 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandEightHundredTwentyWOneHundredSixteenThStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 658 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandEightHundredTwentyWOneHundredSixteenThStreetMember |  |  |
8835 W. 116th Circle [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Broomfield, CO |  |  |
Initial Cost of Land | 1,151 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandEightHundredThirtyFiveWOneHundredSixteenThStreetMember |  |  |
Building and Improvements | 6,523 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandEightHundredThirtyFiveWOneHundredSixteenThStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,410 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandEightHundredThirtyFiveWOneHundredSixteenThStreetMember |  |  |
Land | 1,304 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandEightHundredThirtyFiveWOneHundredSixteenThStreetMember |  |  |
Building and improvements | 7,780 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandEightHundredThirtyFiveWOneHundredSixteenThStreetMember |  |  |
Total | 9,084 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandEightHundredThirtyFiveWOneHundredSixteenThStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 2,445 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandEightHundredThirtyFiveWOneHundredSixteenThStreetMember |  |  |
18150 E. 32nd Place [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Aurora, CO |  |  |
Encumbrances |  | 1,824 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EighteenThousandOneHundredFiftyEThirtyTwoNdStreetMember |  |
Initial Cost of Land | 563 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EighteenThousandOneHundredFiftyEThirtyTwoNdStreetMember |  |  |
Building and Improvements | 3,188 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EighteenThousandOneHundredFiftyEThirtyTwoNdStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 226 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EighteenThousandOneHundredFiftyEThirtyTwoNdStreetMember |  |  |
Land | 572 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EighteenThousandOneHundredFiftyEThirtyTwoNdStreetMember |  |  |
Building and improvements | 3,405 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EighteenThousandOneHundredFiftyEThirtyTwoNdStreetMember |  |  |
Total | 3,977 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EighteenThousandOneHundredFiftyEThirtyTwoNdStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 1,105 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EighteenThousandOneHundredFiftyEThirtyTwoNdStreetMember |  |  |
3400 Fraser Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Aurora, CO |  |  |
Encumbrances |  | 2,155 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThousandFourHundredFraserStreetMember |  |
Initial Cost of Land | 616 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThousandFourHundredFraserStreetMember |  |  |
Building and Improvements | 3,593 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThousandFourHundredFraserStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (184)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThousandFourHundredFraserStreetMember |  |  |
Land | 620 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThousandFourHundredFraserStreetMember |  |  |
Building and improvements | 3,405 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThousandFourHundredFraserStreetMember |  |  |
Total | 4,025 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThousandFourHundredFraserStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 1,005 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThousandFourHundredFraserStreetMember |  |  |
7005 E. 46th Avenue Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Denver, CO |  |  |
Encumbrances |  | 1,348 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandFiveEFortySixThAvenueDriveMember |  |
Initial Cost of Land | 512 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandFiveEFortySixThAvenueDriveMember |  |  |
Building and Improvements | 2,025 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandFiveEFortySixThAvenueDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 32 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandFiveEFortySixThAvenueDriveMember |  |  |
Land | 517 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandFiveEFortySixThAvenueDriveMember |  |  |
Building and improvements | 2,052 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandFiveEFortySixThAvenueDriveMember |  |  |
Total | 2,569 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandFiveEFortySixThAvenueDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 682 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandFiveEFortySixThAvenueDriveMember |  |  |
4001 Salazar Way [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Frederick, CO |  |  |
Initial Cost of Land | 1,271 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandOneSalazarWayMember |  |  |
Building and Improvements | 6,508 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandOneSalazarWayMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (773)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandOneSalazarWayMember |  |  |
Land | 1,276 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandOneSalazarWayMember |  |  |
Building and improvements | 5,730 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandOneSalazarWayMember |  |  |
Total | 7,006 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandOneSalazarWayMember |  |  |
Accumulated depreciation 12/31/2012 | 1,360 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandOneSalazarWayMember |  |  |
5909-5915 N. Broadway [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Denver, CO |  |  |
Encumbrances |  | 898 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThousandNineHundredNineAndFiveThousandNineHundredFifteenBroadwayMember |  |
Initial Cost of Land | 495 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThousandNineHundredNineAndFiveThousandNineHundredFifteenBroadwayMember |  |  |
Building and Improvements | 1,268 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThousandNineHundredNineAndFiveThousandNineHundredFifteenBroadwayMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 107 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThousandNineHundredNineAndFiveThousandNineHundredFifteenBroadwayMember |  |  |
Land | 500 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThousandNineHundredNineAndFiveThousandNineHundredFifteenBroadwayMember |  |  |
Building and improvements | 1,370 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThousandNineHundredNineAndFiveThousandNineHundredFifteenBroadwayMember |  |  |
Total | 1,870 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThousandNineHundredNineAndFiveThousandNineHundredFifteenBroadwayMember |  |  |
Accumulated depreciation 12/31/2012 | 566 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThousandNineHundredNineAndFiveThousandNineHundredFifteenBroadwayMember |  |  |
2406-2416 Walnut Ridge [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Dallas, TX |  |  |
Initial Cost of Land | 178 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourZeroSixToTwoFourOneSixWalnutRidgeMember |  |  |
Building and Improvements | 1,006 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourZeroSixToTwoFourOneSixWalnutRidgeMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 633 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourZeroSixToTwoFourOneSixWalnutRidgeMember |  |  |
Land | 172 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourZeroSixToTwoFourOneSixWalnutRidgeMember |  |  |
Building and improvements | 1,645 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourZeroSixToTwoFourOneSixWalnutRidgeMember |  |  |
Total | 1,817 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourZeroSixToTwoFourOneSixWalnutRidgeMember |  |  |
Accumulated depreciation 12/31/2012 | 603 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourZeroSixToTwoFourOneSixWalnutRidgeMember |  |  |
2401-2419 Walnut Ridge [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Dallas, TX |  |  |
Initial Cost of Land | 148 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourZeroOneToTwoFourOneNineWalnutRidgeMember |  |  |
Building and Improvements | 839 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourZeroOneToTwoFourOneNineWalnutRidgeMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 416 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourZeroOneToTwoFourOneNineWalnutRidgeMember |  |  |
Land | 142 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourZeroOneToTwoFourOneNineWalnutRidgeMember |  |  |
Building and improvements | 1,261 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourZeroOneToTwoFourOneNineWalnutRidgeMember |  |  |
Total | 1,403 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourZeroOneToTwoFourOneNineWalnutRidgeMember |  |  |
Accumulated depreciation 12/31/2012 | 441 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourZeroOneToTwoFourOneNineWalnutRidgeMember |  |  |
900-906 Great Southwest Pkwy [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Arlington, TX |  |  |
Initial Cost of Land | 237 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineZeroZeroToNineZeroSixGreatSouthwestPkwyMember |  |  |
Building and Improvements | 1,342 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineZeroZeroToNineZeroSixGreatSouthwestPkwyMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 638 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineZeroZeroToNineZeroSixGreatSouthwestPkwyMember |  |  |
Land | 270 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineZeroZeroToNineZeroSixGreatSouthwestPkwyMember |  |  |
Building and improvements | 1,947 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineZeroZeroToNineZeroSixGreatSouthwestPkwyMember |  |  |
Total | 2,217 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineZeroZeroToNineZeroSixGreatSouthwestPkwyMember |  |  |
Accumulated depreciation 12/31/2012 | 837 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineZeroZeroToNineZeroSixGreatSouthwestPkwyMember |  |  |
3000 West Commerce [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Dallas, TX |  |  |
Initial Cost of Land | 456 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroZeroZeroWestCommerceMember |  |  |
Building and Improvements | 2,584 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroZeroZeroWestCommerceMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,225 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroZeroZeroWestCommerceMember |  |  |
Land | 469 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroZeroZeroWestCommerceMember |  |  |
Building and improvements | 3,796 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroZeroZeroWestCommerceMember |  |  |
Total | 4,265 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroZeroZeroWestCommerceMember |  |  |
Accumulated depreciation 12/31/2012 | 1,498 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroZeroZeroWestCommerceMember |  |  |
3030 Hansboro [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Dallas, TX |  |  |
Initial Cost of Land | 266 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroThreeZeroHansboroMember |  |  |
Building and Improvements | 1,510 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroThreeZeroHansboroMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (664)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroThreeZeroHansboroMember |  |  |
Land | 87 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroThreeZeroHansboroMember |  |  |
Building and improvements | 1,025 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroThreeZeroHansboroMember |  |  |
Total | 1,112 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroThreeZeroHansboroMember |  |  |
Accumulated depreciation 12/31/2012 | 643 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroThreeZeroHansboroMember |  |  |
405-407 113th [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Arlington, TX |  |  |
Initial Cost of Land | 181 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourZeroFiveToFourZeroSevenOneOneThreeMember |  |  |
Building and Improvements | 1,026 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourZeroFiveToFourZeroSevenOneOneThreeMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 511 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourZeroFiveToFourZeroSevenOneOneThreeMember |  |  |
Land | 185 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourZeroFiveToFourZeroSevenOneOneThreeMember |  |  |
Building and improvements | 1,533 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourZeroFiveToFourZeroSevenOneOneThreeMember |  |  |
Total | 1,718 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourZeroFiveToFourZeroSevenOneOneThreeMember |  |  |
Accumulated depreciation 12/31/2012 | 618 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourZeroFiveToFourZeroSevenOneOneThreeMember |  |  |
816 111th Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Arlington, TX |  |  |
Encumbrances | 857 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightOneSixOneOneOneStreetMember |  |  |
Initial Cost of Land | 251 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightOneSixOneOneOneStreetMember |  |  |
Building and Improvements | 1,421 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightOneSixOneOneOneStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 195 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightOneSixOneOneOneStreetMember |  |  |
Land | 258 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightOneSixOneOneOneStreetMember |  |  |
Building and improvements | 1,609 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightOneSixOneOneOneStreetMember |  |  |
Total | 1,867 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightOneSixOneOneOneStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 700 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightOneSixOneOneOneStreetMember |  |  |
7427 Dogwood Park [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Richland Hills, TX |  |  |
Initial Cost of Land | 96 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourTwoSevenDogwoodParkMember |  |  |
Building and Improvements | 532 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourTwoSevenDogwoodParkMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 302 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourTwoSevenDogwoodParkMember |  |  |
Land | 102 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourTwoSevenDogwoodParkMember |  |  |
Building and improvements | 828 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourTwoSevenDogwoodParkMember |  |  |
Total | 930 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourTwoSevenDogwoodParkMember |  |  |
Accumulated depreciation 12/31/2012 | 298 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourTwoSevenDogwoodParkMember |  |  |
7348-54 Tower Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Richland Hills, TX |  |  |
Initial Cost of Land | 88 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThreeFourEightToFiveFourTowerStreetMember |  |  |
Building and Improvements | 489 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThreeFourEightToFiveFourTowerStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 213 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThreeFourEightToFiveFourTowerStreetMember |  |  |
Land | 94 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThreeFourEightToFiveFourTowerStreetMember |  |  |
Building and improvements | 696 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThreeFourEightToFiveFourTowerStreetMember |  |  |
Total | 790 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThreeFourEightToFiveFourTowerStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 268 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThreeFourEightToFiveFourTowerStreetMember |  |  |
7339-41 Tower Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Richland Hills, TX |  |  |
Initial Cost of Land | 98 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThreeThreeNineToFourOneTowerStreetMember |  |  |
Building and Improvements | 541 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThreeThreeNineToFourOneTowerStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 180 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThreeThreeNineToFourOneTowerStreetMember |  |  |
Land | 104 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThreeThreeNineToFourOneTowerStreetMember |  |  |
Building and improvements | 715 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThreeThreeNineToFourOneTowerStreetMember |  |  |
Total | 819 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThreeThreeNineToFourOneTowerStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 266 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThreeThreeNineToFourOneTowerStreetMember |  |  |
7437-45 Tower Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Richland Hills, TX |  |  |
Initial Cost of Land | 102 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourThreeSevenToFourFiveTowerStreetMember |  |  |
Building and Improvements | 563 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourThreeSevenToFourFiveTowerStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 294 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourThreeSevenToFourFiveTowerStreetMember |  |  |
Land | 108 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourThreeSevenToFourFiveTowerStreetMember |  |  |
Building and improvements | 851 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourThreeSevenToFourFiveTowerStreetMember |  |  |
Total | 959 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourThreeSevenToFourFiveTowerStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 302 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourThreeSevenToFourFiveTowerStreetMember |  |  |
7331-59 Airport Freeway [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Richland Hills, TX |  |  |
Encumbrances | 1,655 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThreeThreeOneToFiveNineAirportFreewayMember |  |  |
Initial Cost of Land | 354 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThreeThreeOneToFiveNineAirportFreewayMember |  |  |
Building and Improvements | 1,958 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThreeThreeOneToFiveNineAirportFreewayMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 368 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThreeThreeOneToFiveNineAirportFreewayMember |  |  |
Land | 372 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThreeThreeOneToFiveNineAirportFreewayMember |  |  |
Building and improvements | 2,308 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThreeThreeOneToFiveNineAirportFreewayMember |  |  |
Total | 2,680 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThreeThreeOneToFiveNineAirportFreewayMember |  |  |
Accumulated depreciation 12/31/2012 | 904 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThreeThreeOneToFiveNineAirportFreewayMember |  |  |
7338-60 Dogwood Park [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Richland Hills, TX |  |  |
Initial Cost of Land | 106 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThreeThreeEightToSixZeroDogwoodParkMember |  |  |
Building and Improvements | 587 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThreeThreeEightToSixZeroDogwoodParkMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 244 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThreeThreeEightToSixZeroDogwoodParkMember |  |  |
Land | 112 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThreeThreeEightToSixZeroDogwoodParkMember |  |  |
Building and improvements | 825 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThreeThreeEightToSixZeroDogwoodParkMember |  |  |
Total | 937 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThreeThreeEightToSixZeroDogwoodParkMember |  |  |
Accumulated depreciation 12/31/2012 | 289 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThreeThreeEightToSixZeroDogwoodParkMember |  |  |
7450-70 Dogwood Park [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Richland Hills, TX |  |  |
Initial Cost of Land | 106 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourFiveZeroToSevenZeroDogwoodParkMember |  |  |
Building and Improvements | 584 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourFiveZeroToSevenZeroDogwoodParkMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 136 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourFiveZeroToSevenZeroDogwoodParkMember |  |  |
Land | 112 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourFiveZeroToSevenZeroDogwoodParkMember |  |  |
Building and improvements | 714 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourFiveZeroToSevenZeroDogwoodParkMember |  |  |
Total | 826 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourFiveZeroToSevenZeroDogwoodParkMember |  |  |
Accumulated depreciation 12/31/2012 | 273 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourFiveZeroToSevenZeroDogwoodParkMember |  |  |
7423-49 Airport Freeway [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Richland Hills, TX |  |  |
Encumbrances | 1,450 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourTwoThreeToFourNineAirportFreewayMember |  |  |
Initial Cost of Land | 293 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourTwoThreeToFourNineAirportFreewayMember |  |  |
Building and Improvements | 1,621 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourTwoThreeToFourNineAirportFreewayMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 434 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourTwoThreeToFourNineAirportFreewayMember |  |  |
Land | 308 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourTwoThreeToFourNineAirportFreewayMember |  |  |
Building and improvements | 2,040 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourTwoThreeToFourNineAirportFreewayMember |  |  |
Total | 2,348 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourTwoThreeToFourNineAirportFreewayMember |  |  |
Accumulated depreciation 12/31/2012 | 755 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourTwoThreeToFourNineAirportFreewayMember |  |  |
7400 Whitehall Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Richland Hills, TX |  |  |
Initial Cost of Land | 109 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourZeroZeroWhitehallStreetMember |  |  |
Building and Improvements | 603 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourZeroZeroWhitehallStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 95 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourZeroZeroWhitehallStreetMember |  |  |
Land | 115 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourZeroZeroWhitehallStreetMember |  |  |
Building and improvements | 692 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourZeroZeroWhitehallStreetMember |  |  |
Total | 807 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourZeroZeroWhitehallStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 266 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourZeroZeroWhitehallStreetMember |  |  |
1602-1654 Terre Colony [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Dallas, TX |  |  |
Encumbrances | 1,788 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixZeroTwoToOneSixFiveFourTerreColonyMember |  |  |
Initial Cost of Land | 458 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixZeroTwoToOneSixFiveFourTerreColonyMember |  |  |
Building and Improvements | 2,596 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixZeroTwoToOneSixFiveFourTerreColonyMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 845 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixZeroTwoToOneSixFiveFourTerreColonyMember |  |  |
Land | 468 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixZeroTwoToOneSixFiveFourTerreColonyMember |  |  |
Building and improvements | 3,431 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixZeroTwoToOneSixFiveFourTerreColonyMember |  |  |
Total | 3,899 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixZeroTwoToOneSixFiveFourTerreColonyMember |  |  |
Accumulated depreciation 12/31/2012 | 1,148 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixZeroTwoToOneSixFiveFourTerreColonyMember |  |  |
2351-2355 Merritt Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Garland, TX |  |  |
Initial Cost of Land | 101 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeFiveOneToTwoThreeFiveFiveMerrittDriveMember |  |  |
Building and Improvements | 574 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeFiveOneToTwoThreeFiveFiveMerrittDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 104 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeFiveOneToTwoThreeFiveFiveMerrittDriveMember |  |  |
Land | 92 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeFiveOneToTwoThreeFiveFiveMerrittDriveMember |  |  |
Building and improvements | 687 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeFiveOneToTwoThreeFiveFiveMerrittDriveMember |  |  |
Total | 779 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeFiveOneToTwoThreeFiveFiveMerrittDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 242 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeFiveOneToTwoThreeFiveFiveMerrittDriveMember |  |  |
2220 Merritt Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Garland, TX |  |  |
Initial Cost of Land | 352 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoTwoTwoZeroMerrittDriveMember |  |  |
Building and Improvements | 1,993 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoTwoTwoZeroMerrittDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 145 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoTwoTwoZeroMerrittDriveMember |  |  |
Land | 316 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoTwoTwoZeroMerrittDriveMember |  |  |
Building and improvements | 2,174 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoTwoTwoZeroMerrittDriveMember |  |  |
Total | 2,490 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoTwoTwoZeroMerrittDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 661 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoTwoTwoZeroMerrittDriveMember |  |  |
2010 Merritt Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Garland, TX |  |  |
Initial Cost of Land | 350 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroOneZeroMerrittDriveMember |  |  |
Building and Improvements | 1,981 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroOneZeroMerrittDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 55 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroOneZeroMerrittDriveMember |  |  |
Land | 318 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroOneZeroMerrittDriveMember |  |  |
Building and improvements | 2,068 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroOneZeroMerrittDriveMember |  |  |
Total | 2,386 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroOneZeroMerrittDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 668 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroOneZeroMerrittDriveMember |  |  |
2363 Merritt Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Garland, TX |  |  |
Initial Cost of Land | 73 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeSixThreeMerrittDriveMember |  |  |
Building and Improvements | 412 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeSixThreeMerrittDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (8)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeSixThreeMerrittDriveMember |  |  |
Land | 47 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeSixThreeMerrittDriveMember |  |  |
Building and improvements | 430 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeSixThreeMerrittDriveMember |  |  |
Total | 477 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeSixThreeMerrittDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 159 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeSixThreeMerrittDriveMember |  |  |
2447 Merritt Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Garland, TX |  |  |
Initial Cost of Land | 70 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourFourSevenMerrittDriveMember |  |  |
Building and Improvements | 395 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourFourSevenMerrittDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (166)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourFourSevenMerrittDriveMember |  |  |
Land | 23 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourFourSevenMerrittDriveMember |  |  |
Building and improvements | 276 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourFourSevenMerrittDriveMember |  |  |
Total | 299 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourFourSevenMerrittDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 156 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourFourSevenMerrittDriveMember |  |  |
2465-2475 Merritt Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Garland, TX |  |  |
Initial Cost of Land | 91 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourSixFiveToTwoFourSevenFiveMerrittDriveMember |  |  |
Building and Improvements | 514 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourSixFiveToTwoFourSevenFiveMerrittDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 39 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourSixFiveToTwoFourSevenFiveMerrittDriveMember |  |  |
Land | 71 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourSixFiveToTwoFourSevenFiveMerrittDriveMember |  |  |
Building and improvements | 573 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourSixFiveToTwoFourSevenFiveMerrittDriveMember |  |  |
Total | 644 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourSixFiveToTwoFourSevenFiveMerrittDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 227 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourSixFiveToTwoFourSevenFiveMerrittDriveMember |  |  |
2485-2505 Merritt Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Garland, TX |  |  |
Initial Cost of Land | 431 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourEightFiveToTwoFiveZeroFiveMerrittDriveMember |  |  |
Building and Improvements | 2,440 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourEightFiveToTwoFiveZeroFiveMerrittDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 762 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourEightFiveToTwoFiveZeroFiveMerrittDriveMember |  |  |
Land | 426 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourEightFiveToTwoFiveZeroFiveMerrittDriveMember |  |  |
Building and improvements | 3,207 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourEightFiveToTwoFiveZeroFiveMerrittDriveMember |  |  |
Total | 3,633 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourEightFiveToTwoFiveZeroFiveMerrittDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,196 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourEightFiveToTwoFiveZeroFiveMerrittDriveMember |  |  |
2110 Hutton Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Carrolton, TX |  |  |
Initial Cost of Land | 374 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneOneZeroHuttonDriveMember |  |  |
Building and Improvements | 2,117 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneOneZeroHuttonDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 117 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneOneZeroHuttonDriveMember |  |  |
Land | 255 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneOneZeroHuttonDriveMember |  |  |
Building and improvements | 2,353 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneOneZeroHuttonDriveMember |  |  |
Total | 2,608 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneOneZeroHuttonDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 844 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneOneZeroHuttonDriveMember |  |  |
2025 McKenzie Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Carrolton, TX |  |  |
Encumbrances | 1,398 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroTwoFiveMckenzieDriveMember |  |  |
Initial Cost of Land | 437 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroTwoFiveMckenzieDriveMember |  |  |
Building and Improvements | 2,478 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroTwoFiveMckenzieDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 133 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroTwoFiveMckenzieDriveMember |  |  |
Land | 442 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroTwoFiveMckenzieDriveMember |  |  |
Building and improvements | 2,606 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroTwoFiveMckenzieDriveMember |  |  |
Total | 3,048 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroTwoFiveMckenzieDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 896 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroTwoFiveMckenzieDriveMember |  |  |
2019 McKenzie Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Carrolton, TX |  |  |
Encumbrances | 1,706 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroOneNineMckenzieDriveMember |  |  |
Initial Cost of Land | 502 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroOneNineMckenzieDriveMember |  |  |
Building and Improvements | 2,843 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroOneNineMckenzieDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 374 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroOneNineMckenzieDriveMember |  |  |
Land | 507 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroOneNineMckenzieDriveMember |  |  |
Building and improvements | 3,212 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroOneNineMckenzieDriveMember |  |  |
Total | 3,719 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroOneNineMckenzieDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,122 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroOneNineMckenzieDriveMember |  |  |
2029-2035 McKenzie Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Carrolton, TX |  |  |
Encumbrances | 1,502 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroTwoNineToTwoZeroThreeFiveMckenzieDriveMember |  |  |
Initial Cost of Land | 306 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroTwoNineToTwoZeroThreeFiveMckenzieDriveMember |  |  |
Building and Improvements | 1,870 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroTwoNineToTwoZeroThreeFiveMckenzieDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 236 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroTwoNineToTwoZeroThreeFiveMckenzieDriveMember |  |  |
Land | 306 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroTwoNineToTwoZeroThreeFiveMckenzieDriveMember |  |  |
Building and improvements | 2,106 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroTwoNineToTwoZeroThreeFiveMckenzieDriveMember |  |  |
Total | 2,412 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroTwoNineToTwoZeroThreeFiveMckenzieDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 741 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroTwoNineToTwoZeroThreeFiveMckenzieDriveMember |  |  |
2015 McKenzie Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Carrolton, TX |  |  |
Encumbrances | 2,475 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroOneFiveMckenzieDriveMember |  |  |
Initial Cost of Land | 510 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroOneFiveMckenzieDriveMember |  |  |
Building and Improvements | 2,891 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroOneFiveMckenzieDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 402 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroOneFiveMckenzieDriveMember |  |  |
Land | 516 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroOneFiveMckenzieDriveMember |  |  |
Building and improvements | 3,287 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroOneFiveMckenzieDriveMember |  |  |
Total | 3,803 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroOneFiveMckenzieDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,109 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroOneFiveMckenzieDriveMember |  |  |
2009 McKenzie Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Carrolton, TX |  |  |
Encumbrances | 2,404 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroNineMckenzieDriveMember |  |  |
Initial Cost of Land | 476 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroNineMckenzieDriveMember |  |  |
Building and Improvements | 2,699 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroNineMckenzieDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 519 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroNineMckenzieDriveMember |  |  |
Land | 481 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroNineMckenzieDriveMember |  |  |
Building and improvements | 3,213 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroNineMckenzieDriveMember |  |  |
Total | 3,694 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroNineMckenzieDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,092 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroNineMckenzieDriveMember |  |  |
900-1100 Avenue S [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Grand Prairie, TX |  |  |
Encumbrances | 2,344 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineZeroZeroOneOneZeroZeroAvenueSMember |  |  |
Initial Cost of Land | 623 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineZeroZeroOneOneZeroZeroAvenueSMember |  |  |
Building and Improvements | 3,528 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineZeroZeroOneOneZeroZeroAvenueSMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 959 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineZeroZeroOneOneZeroZeroAvenueSMember |  |  |
Land | 629 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineZeroZeroOneOneZeroZeroAvenueSMember |  |  |
Building and improvements | 4,481 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineZeroZeroOneOneZeroZeroAvenueSMember |  |  |
Total | 5,110 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineZeroZeroOneOneZeroZeroAvenueSMember |  |  |
Accumulated depreciation 12/31/2012 | 1,250 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineZeroZeroOneOneZeroZeroAvenueSMember |  |  |
Plano Crossing [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Plano, TX |  |  |
Encumbrances | 9,157 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_PlanoCrossingFMember |  |  |
Initial Cost of Land | 1,961 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_PlanoCrossingFMember |  |  |
Building and Improvements | 11,112 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_PlanoCrossingFMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 997 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_PlanoCrossingFMember |  |  |
Land | 1,981 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_PlanoCrossingFMember |  |  |
Building and improvements | 12,089 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_PlanoCrossingFMember |  |  |
Total | 14,070 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_PlanoCrossingFMember |  |  |
Accumulated depreciation 12/31/2012 | 3,660 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_PlanoCrossingFMember |  |  |
7413A-C Dogwood Park [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Richland Hills, TX |  |  |
Initial Cost of Land | 110 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourOneThreeCDogwoodParkMember |  |  |
Building and Improvements | 623 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourOneThreeCDogwoodParkMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 245 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourOneThreeCDogwoodParkMember |  |  |
Land | 111 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourOneThreeCDogwoodParkMember |  |  |
Building and improvements | 867 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourOneThreeCDogwoodParkMember |  |  |
Total | 978 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourOneThreeCDogwoodParkMember |  |  |
Accumulated depreciation 12/31/2012 | 269 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourOneThreeCDogwoodParkMember |  |  |
7450 Tower Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Richland Hills, TX |  |  |
Initial Cost of Land | 36 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourFiveZeroTowerStreetMember |  |  |
Building and Improvements | 204 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourFiveZeroTowerStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 103 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourFiveZeroTowerStreetMember |  |  |
Land | 36 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourFiveZeroTowerStreetMember |  |  |
Building and improvements | 307 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourFiveZeroTowerStreetMember |  |  |
Total | 343 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourFiveZeroTowerStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 111 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourFiveZeroTowerStreetMember |  |  |
7436 Tower Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Richland Hills, TX |  |  |
Initial Cost of Land | 57 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourThreeSixTowerStreetMember |  |  |
Building and Improvements | 324 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourThreeSixTowerStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 196 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourThreeSixTowerStreetMember |  |  |
Land | 58 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourThreeSixTowerStreetMember |  |  |
Building and improvements | 519 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourThreeSixTowerStreetMember |  |  |
Total | 577 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourThreeSixTowerStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 177 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourThreeSixTowerStreetMember |  |  |
7426 Tower Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Richland Hills, TX |  |  |
Initial Cost of Land | 76 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourTwoSixTowerStreetMember |  |  |
Building and Improvements | 429 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourTwoSixTowerStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 186 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourTwoSixTowerStreetMember |  |  |
Land | 76 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourTwoSixTowerStreetMember |  |  |
Building and improvements | 615 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourTwoSixTowerStreetMember |  |  |
Total | 691 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourTwoSixTowerStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 160 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourTwoSixTowerStreetMember |  |  |
7427-7429 Tower Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Richland Hills, TX |  |  |
Initial Cost of Land | 75 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourTwoSevenSevenFourTwoNineTowerStreetMember |  |  |
Building and Improvements | 427 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourTwoSevenSevenFourTwoNineTowerStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 163 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourTwoSevenSevenFourTwoNineTowerStreetMember |  |  |
Land | 76 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourTwoSevenSevenFourTwoNineTowerStreetMember |  |  |
Building and improvements | 589 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourTwoSevenSevenFourTwoNineTowerStreetMember |  |  |
Total | 665 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourTwoSevenSevenFourTwoNineTowerStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 219 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourTwoSevenSevenFourTwoNineTowerStreetMember |  |  |
2840-2842 Handley Ederville Rd [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Richland Hills, TX |  |  |
Initial Cost of Land | 112 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourZeroTwoEightFourTwoHandleyEdervilleRdMember |  |  |
Building and Improvements | 635 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourZeroTwoEightFourTwoHandleyEdervilleRdMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 52 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourZeroTwoEightFourTwoHandleyEdervilleRdMember |  |  |
Land | 113 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourZeroTwoEightFourTwoHandleyEdervilleRdMember |  |  |
Building and improvements | 686 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourZeroTwoEightFourTwoHandleyEdervilleRdMember |  |  |
Total | 799 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourZeroTwoEightFourTwoHandleyEdervilleRdMember |  |  |
Accumulated depreciation 12/31/2012 | 208 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourZeroTwoEightFourTwoHandleyEdervilleRdMember |  |  |
825-827 Avenue H D [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Arlington, TX |  |  |
Encumbrances | 2,481 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightTwoFiveEightTwoSevenAvenueHDMember |  |  |
Initial Cost of Land | 600 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightTwoFiveEightTwoSevenAvenueHDMember |  |  |
Building and Improvements | 3,006 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightTwoFiveEightTwoSevenAvenueHDMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 67 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightTwoFiveEightTwoSevenAvenueHDMember |  |  |
Land | 604 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightTwoFiveEightTwoSevenAvenueHDMember |  |  |
Building and improvements | 3,069 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightTwoFiveEightTwoSevenAvenueHDMember |  |  |
Total | 3,673 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightTwoFiveEightTwoSevenAvenueHDMember |  |  |
Accumulated depreciation 12/31/2012 | 1,229 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightTwoFiveEightTwoSevenAvenueHDMember |  |  |
1200-16 Avenue H D [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Arlington, TX |  |  |
Encumbrances | 1,731 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoZeroZeroOneSixAvenueHDMember |  |  |
Initial Cost of Land | 600 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoZeroZeroOneSixAvenueHDMember |  |  |
Building and Improvements | 2,846 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoZeroZeroOneSixAvenueHDMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 329 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoZeroZeroOneSixAvenueHDMember |  |  |
Land | 604 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoZeroZeroOneSixAvenueHDMember |  |  |
Building and improvements | 3,171 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoZeroZeroOneSixAvenueHDMember |  |  |
Total | 3,775 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoZeroZeroOneSixAvenueHDMember |  |  |
Accumulated depreciation 12/31/2012 | 928 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoZeroZeroOneSixAvenueHDMember |  |  |
1322-66 W. North Carrier Parkway [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Grand Prairie, TX |  |  |
Encumbrances | 4,739 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeTwoTwoSixSixNCarrierParkwayEMember |  |  |
Initial Cost of Land | 1,000 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeTwoTwoSixSixNCarrierParkwayEMember |  |  |
Building and Improvements | 5,012 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeTwoTwoSixSixNCarrierParkwayEMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,003 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeTwoTwoSixSixNCarrierParkwayEMember |  |  |
Land | 1,006 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeTwoTwoSixSixNCarrierParkwayEMember |  |  |
Building and improvements | 6,009 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeTwoTwoSixSixNCarrierParkwayEMember |  |  |
Total | 7,015 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeTwoTwoSixSixNCarrierParkwayEMember |  |  |
Accumulated depreciation 12/31/2012 | 1,796 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeTwoTwoSixSixNCarrierParkwayEMember |  |  |
2401-2407 Centennial Dr [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Arlington, TX |  |  |
Encumbrances |  | 2,143 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourZeroOneTwoFourZeroSevenCentennialMember |  |
Initial Cost of Land | 600 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourZeroOneTwoFourZeroSevenCentennialMember |  |  |
Building and Improvements | 2,534 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourZeroOneTwoFourZeroSevenCentennialMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (50)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourZeroOneTwoFourZeroSevenCentennialMember |  |  |
Land | 604 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourZeroOneTwoFourZeroSevenCentennialMember |  |  |
Building and improvements | 2,480 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourZeroOneTwoFourZeroSevenCentennialMember |  |  |
Total | 3,084 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourZeroOneTwoFourZeroSevenCentennialMember |  |  |
Accumulated depreciation 12/31/2012 | 991 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourZeroOneTwoFourZeroSevenCentennialMember |  |  |
3111 West Commerce Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Dallas, TX |  |  |
Encumbrances |  | 3,802 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeOneOneOneWestCommerceMember |  |
Initial Cost of Land | 1,000 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeOneOneOneWestCommerceMember |  |  |
Building and Improvements | 3,364 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeOneOneOneWestCommerceMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,264 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeOneOneOneWestCommerceMember |  |  |
Land | 1,011 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeOneOneOneWestCommerceMember |  |  |
Building and improvements | 4,617 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeOneOneOneWestCommerceMember |  |  |
Total | 5,628 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeOneOneOneWestCommerceMember |  |  |
Accumulated depreciation 12/31/2012 | 1,419 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeOneOneOneWestCommerceMember |  |  |
13800 Senlac Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Farmers Ranch, TX |  |  |
Encumbrances |  | 3,142 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeEightZeroZeroSenlacDriveMember |  |
Initial Cost of Land | 823 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeEightZeroZeroSenlacDriveMember |  |  |
Building and Improvements | 4,042 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeEightZeroZeroSenlacDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (214)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeEightZeroZeroSenlacDriveMember |  |  |
Land | 825 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeEightZeroZeroSenlacDriveMember |  |  |
Building and improvements | 3,826 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeEightZeroZeroSenlacDriveMember |  |  |
Total | 4,651 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeEightZeroZeroSenlacDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,306 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeEightZeroZeroSenlacDriveMember |  |  |
801-831 S Great Southwest Pkwy [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Grand Prairie, TX |  |  |
Initial Cost of Land | 2,581 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightZeroOneEightThreeOneSGreatSouthwestGMember |  |  |
Building and Improvements | 16,556 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightZeroOneEightThreeOneSGreatSouthwestGMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 53 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightZeroOneEightThreeOneSGreatSouthwestGMember |  |  |
Land | 2,586 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightZeroOneEightThreeOneSGreatSouthwestGMember |  |  |
Building and improvements | 16,604 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightZeroOneEightThreeOneSGreatSouthwestGMember |  |  |
Total | 19,190 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightZeroOneEightThreeOneSGreatSouthwestGMember |  |  |
Accumulated depreciation 12/31/2012 | 7,867 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightZeroOneEightThreeOneSGreatSouthwestGMember |  |  |
801 Heinz Way [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Grand Prairie, TX |  |  |
Encumbrances |  | 2,618 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightZeroOneHeinzWayMember |  |
Initial Cost of Land | 599 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightZeroOneHeinzWayMember |  |  |
Building and Improvements | 3,327 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightZeroOneHeinzWayMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 315 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightZeroOneHeinzWayMember |  |  |
Land | 601 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightZeroOneHeinzWayMember |  |  |
Building and improvements | 3,640 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightZeroOneHeinzWayMember |  |  |
Total | 4,241 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightZeroOneHeinzWayMember |  |  |
Accumulated depreciation 12/31/2012 | 1,338 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightZeroOneHeinzWayMember |  |  |
901-937 Heinz Way [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Grand Prairie, TX |  |  |
Encumbrances |  | 2,035 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineZeroOneNineThreeSevenHeinzWayMember |  |
Initial Cost of Land | 493 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineZeroOneNineThreeSevenHeinzWayMember |  |  |
Building and Improvements | 2,758 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineZeroOneNineThreeSevenHeinzWayMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 45 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineZeroOneNineThreeSevenHeinzWayMember |  |  |
Land | 481 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineZeroOneNineThreeSevenHeinzWayMember |  |  |
Building and improvements | 2,815 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineZeroOneNineThreeSevenHeinzWayMember |  |  |
Total | 3,296 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineZeroOneNineThreeSevenHeinzWayMember |  |  |
Accumulated depreciation 12/31/2012 | 1,101 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineZeroOneNineThreeSevenHeinzWayMember |  |  |
3301 Century Circle [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Irving, TX |  |  |
Encumbrances |  | 2,110 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThreeZeroOneCenturyCircleMember |  |
Initial Cost of Land | 760 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThreeZeroOneCenturyCircleMember |  |  |
Building and Improvements | 3,856 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThreeZeroOneCenturyCircleMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (16)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThreeZeroOneCenturyCircleMember |  |  |
Land | 771 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThreeZeroOneCenturyCircleMember |  |  |
Building and improvements | 3,829 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThreeZeroOneCenturyCircleMember |  |  |
Total | 4,600 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThreeZeroOneCenturyCircleMember |  |  |
Accumulated depreciation 12/31/2012 | 867 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThreeZeroOneCenturyCircleMember |  |  |
3901 W Miller Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Garland, TX |  |  |
Initial Cost of Land | 1,912 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeNineZeroOneWestMillerRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 15,478 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeNineZeroOneWestMillerRoadMember |  |  |
Land | 1,947 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeNineZeroOneWestMillerRoadMember |  |  |
Building and improvements | 15,443 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeNineZeroOneWestMillerRoadMember |  |  |
Total | 17,390 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeNineZeroOneWestMillerRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 2,955 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeNineZeroOneWestMillerRoadMember |  |  |
1731 Thorncroft [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Troy, MI |  |  |
Initial Cost of Land | 331 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandSevenHundredThirtyOneThorncroftMember |  |  |
Building and Improvements | 1,904 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandSevenHundredThirtyOneThorncroftMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 189 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandSevenHundredThirtyOneThorncroftMember |  |  |
Land | 331 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandSevenHundredThirtyOneThorncroftMember |  |  |
Building and improvements | 2,093 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandSevenHundredThirtyOneThorncroftMember |  |  |
Total | 2,424 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandSevenHundredThirtyOneThorncroftMember |  |  |
Accumulated depreciation 12/31/2012 | 1,050 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandSevenHundredThirtyOneThorncroftMember |  |  |
47461 Clipper [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Plymouth Township, MI |  |  |
Initial Cost of Land | 122 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FortySevenThousandFourHundredSixtyOneClipperMember |  |  |
Building and Improvements | 723 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FortySevenThousandFourHundredSixtyOneClipperMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 54 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FortySevenThousandFourHundredSixtyOneClipperMember |  |  |
Land | 122 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FortySevenThousandFourHundredSixtyOneClipperMember |  |  |
Building and improvements | 777 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FortySevenThousandFourHundredSixtyOneClipperMember |  |  |
Total | 899 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FortySevenThousandFourHundredSixtyOneClipperMember |  |  |
Accumulated depreciation 12/31/2012 | 409 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FortySevenThousandFourHundredSixtyOneClipperMember |  |  |
449 Executive Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Troy, MI |  |  |
Initial Cost of Land | 125 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredFortyNineExecutiveDriveMember |  |  |
Building and Improvements | 425 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredFortyNineExecutiveDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,066 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredFortyNineExecutiveDriveMember |  |  |
Land | 218 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredFortyNineExecutiveDriveMember |  |  |
Building and improvements | 1,398 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredFortyNineExecutiveDriveMember |  |  |
Total | 1,616 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredFortyNineExecutiveDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,268 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredFortyNineExecutiveDriveMember |  |  |
501 Executive Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Troy, MI |  |  |
Initial Cost of Land | 71 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveHundredOneExecutiveDriveMember |  |  |
Building and Improvements | 236 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveHundredOneExecutiveDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 678 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveHundredOneExecutiveDriveMember |  |  |
Land | 129 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveHundredOneExecutiveDriveMember |  |  |
Building and improvements | 856 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveHundredOneExecutiveDriveMember |  |  |
Total | 985 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveHundredOneExecutiveDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 659 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveHundredOneExecutiveDriveMember |  |  |
451 Robbins Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Troy, MI |  |  |
Initial Cost of Land | 96 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredFiftyOneRobbinsDriveMember |  |  |
Building and Improvements | 448 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredFiftyOneRobbinsDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 877 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredFiftyOneRobbinsDriveMember |  |  |
Land | 192 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredFiftyOneRobbinsDriveMember |  |  |
Building and improvements | 1,229 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredFiftyOneRobbinsDriveMember |  |  |
Total | 1,421 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredFiftyOneRobbinsDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,104 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourHundredFiftyOneRobbinsDriveMember |  |  |
1416 Meijer Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Troy, MI |  |  |
Initial Cost of Land | 94 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandFourHundredSixteenMeijerDriveMember |  |  |
Building and Improvements | 394 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandFourHundredSixteenMeijerDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 399 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandFourHundredSixteenMeijerDriveMember |  |  |
Land | 121 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandFourHundredSixteenMeijerDriveMember |  |  |
Building and improvements | 766 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandFourHundredSixteenMeijerDriveMember |  |  |
Total | 887 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandFourHundredSixteenMeijerDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 701 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandFourHundredSixteenMeijerDriveMember |  |  |
1624 Meijer Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Troy, MI |  |  |
Initial Cost of Land | 236 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandSixHundredTwentyFourMeijerDriveMember |  |  |
Building and Improvements | 1,406 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandSixHundredTwentyFourMeijerDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,093 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandSixHundredTwentyFourMeijerDriveMember |  |  |
Land | 373 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandSixHundredTwentyFourMeijerDriveMember |  |  |
Building and improvements | 2,362 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandSixHundredTwentyFourMeijerDriveMember |  |  |
Total | 2,735 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandSixHundredTwentyFourMeijerDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,999 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandSixHundredTwentyFourMeijerDriveMember |  |  |
1972 Meijer Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Troy, MI |  |  |
Initial Cost of Land | 315 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandNineHundredSeventyTwoMeijerDriveMember |  |  |
Building and Improvements | 1,301 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandNineHundredSeventyTwoMeijerDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 787 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandNineHundredSeventyTwoMeijerDriveMember |  |  |
Land | 372 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandNineHundredSeventyTwoMeijerDriveMember |  |  |
Building and improvements | 2,031 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandNineHundredSeventyTwoMeijerDriveMember |  |  |
Total | 2,403 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandNineHundredSeventyTwoMeijerDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,555 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandNineHundredSeventyTwoMeijerDriveMember |  |  |
1707 Northwood Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Troy, MI |  |  |
Initial Cost of Land | 95 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandSevenHundredSevenNorthwoodDriveMember |  |  |
Building and Improvements | 262 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandSevenHundredSevenNorthwoodDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,720 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandSevenHundredSevenNorthwoodDriveMember |  |  |
Land | 239 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandSevenHundredSevenNorthwoodDriveMember |  |  |
Building and improvements | 1,838 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandSevenHundredSevenNorthwoodDriveMember |  |  |
Total | 2,077 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandSevenHundredSevenNorthwoodDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,446 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThousandSevenHundredSevenNorthwoodDriveMember |  |  |
1788 Northwood Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Troy, MI |  |  |
Initial Cost of Land | 50 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenEightEightNorthwoodDriveMember |  |  |
Building and Improvements | 196 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenEightEightNorthwoodDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 483 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenEightEightNorthwoodDriveMember |  |  |
Land | 103 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenEightEightNorthwoodDriveMember |  |  |
Building and improvements | 626 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenEightEightNorthwoodDriveMember |  |  |
Total | 729 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenEightEightNorthwoodDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 566 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenEightEightNorthwoodDriveMember |  |  |
1826 Northwood Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Troy, MI |  |  |
Initial Cost of Land | 55 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightTwoSixNorthwoodDriveMember |  |  |
Building and Improvements | 208 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightTwoSixNorthwoodDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 472 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightTwoSixNorthwoodDriveMember |  |  |
Land | 103 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightTwoSixNorthwoodDriveMember |  |  |
Building and improvements | 632 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightTwoSixNorthwoodDriveMember |  |  |
Total | 735 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightTwoSixNorthwoodDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 557 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightTwoSixNorthwoodDriveMember |  |  |
1864 Northwood Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Troy, MI |  |  |
Initial Cost of Land | 57 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightSixFourNorthwoodDriveMember |  |  |
Building and Improvements | 190 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightSixFourNorthwoodDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 489 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightSixFourNorthwoodDriveMember |  |  |
Land | 107 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightSixFourNorthwoodDriveMember |  |  |
Building and improvements | 629 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightSixFourNorthwoodDriveMember |  |  |
Total | 736 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightSixFourNorthwoodDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 573 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightSixFourNorthwoodDriveMember |  |  |
2451 Elliott Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Troy, MI |  |  |
Initial Cost of Land | 78 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourFiveOneElliottAvenueMember |  |  |
Building and Improvements | 319 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourFiveOneElliottAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 733 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourFiveOneElliottAvenueMember |  |  |
Land | 164 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourFiveOneElliottAvenueMember |  |  |
Building and improvements | 966 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourFiveOneElliottAvenueMember |  |  |
Total | 1,130 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourFiveOneElliottAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 786 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourFiveOneElliottAvenueMember |  |  |
2730 Research Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Rochester Hills, MI |  |  |
Initial Cost of Land | 903 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSevenThreeZeroResearchDriveMember |  |  |
Building and Improvements | 4,215 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSevenThreeZeroResearchDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 829 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSevenThreeZeroResearchDriveMember |  |  |
Land | 903 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSevenThreeZeroResearchDriveMember |  |  |
Building and improvements | 5,044 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSevenThreeZeroResearchDriveMember |  |  |
Total | 5,947 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSevenThreeZeroResearchDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 4,093 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSevenThreeZeroResearchDriveMember |  |  |
2791 Research Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Rochester Hills, MI |  |  |
Initial Cost of Land | 557 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSevenNineOneResearchDriveMember |  |  |
Building and Improvements | 2,731 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSevenNineOneResearchDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,017 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSevenNineOneResearchDriveMember |  |  |
Land | 560 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSevenNineOneResearchDriveMember |  |  |
Building and improvements | 3,745 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSevenNineOneResearchDriveMember |  |  |
Total | 4,305 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSevenNineOneResearchDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 2,552 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSevenNineOneResearchDriveMember |  |  |
2871 Research Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Rochester Hills, MI |  |  |
Initial Cost of Land | 324 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightSevenOneResearchDriveMember |  |  |
Building and Improvements | 1,487 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightSevenOneResearchDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 437 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightSevenOneResearchDriveMember |  |  |
Land | 327 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightSevenOneResearchDriveMember |  |  |
Building and improvements | 1,921 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightSevenOneResearchDriveMember |  |  |
Total | 2,248 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightSevenOneResearchDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,420 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightSevenOneResearchDriveMember |  |  |
3011 Research Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Rochester Hills, MI |  |  |
Initial Cost of Land | 457 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroOneOneResearchDriveMember |  |  |
Building and Improvements | 2,104 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroOneOneResearchDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 492 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroOneOneResearchDriveMember |  |  |
Land | 457 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroOneOneResearchDriveMember |  |  |
Building and improvements | 2,596 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroOneOneResearchDriveMember |  |  |
Total | 3,053 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroOneOneResearchDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 2,091 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroOneOneResearchDriveMember |  |  |
2870 Technology Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Rochester Hills, MI |  |  |
Initial Cost of Land | 275 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightSevenZeroTechnologyDriveMember |  |  |
Building and Improvements | 1,262 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightSevenZeroTechnologyDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 356 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightSevenZeroTechnologyDriveMember |  |  |
Land | 279 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightSevenZeroTechnologyDriveMember |  |  |
Building and improvements | 1,614 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightSevenZeroTechnologyDriveMember |  |  |
Total | 1,893 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightSevenZeroTechnologyDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,278 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightSevenZeroTechnologyDriveMember |  |  |
2900 Technology Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Rochester Hills, MI |  |  |
Initial Cost of Land | 214 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineZeroZeroTechnologyDriveMember |  |  |
Building and Improvements | 977 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineZeroZeroTechnologyDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 513 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineZeroZeroTechnologyDriveMember |  |  |
Land | 219 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineZeroZeroTechnologyDriveMember |  |  |
Building and improvements | 1,485 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineZeroZeroTechnologyDriveMember |  |  |
Total | 1,704 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineZeroZeroTechnologyDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 971 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineZeroZeroTechnologyDriveMember |  |  |
2930 Technology Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Rochester Hills, MI |  |  |
Initial Cost of Land | 131 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineThreeZeroTechnologyDriveMember |  |  |
Building and Improvements | 594 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineThreeZeroTechnologyDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 435 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineThreeZeroTechnologyDriveMember |  |  |
Land | 138 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineThreeZeroTechnologyDriveMember |  |  |
Building and improvements | 1,022 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineThreeZeroTechnologyDriveMember |  |  |
Total | 1,160 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineThreeZeroTechnologyDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 698 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineThreeZeroTechnologyDriveMember |  |  |
2950 Technology Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Rochester Hills, MI |  |  |
Initial Cost of Land | 178 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineFiveZeroTechnologyDriveMember |  |  |
Building and Improvements | 819 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineFiveZeroTechnologyDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 368 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineFiveZeroTechnologyDriveMember |  |  |
Land | 185 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineFiveZeroTechnologyDriveMember |  |  |
Building and improvements | 1,180 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineFiveZeroTechnologyDriveMember |  |  |
Total | 1,365 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineFiveZeroTechnologyDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 801 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineFiveZeroTechnologyDriveMember |  |  |
23014 Commerce Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Farmington Hills, MI |  |  |
Initial Cost of Land | 39 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroOneFourCommerceDriveMember |  |  |
Building and Improvements | 203 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroOneFourCommerceDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 189 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroOneFourCommerceDriveMember |  |  |
Land | 56 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroOneFourCommerceDriveMember |  |  |
Building and improvements | 375 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroOneFourCommerceDriveMember |  |  |
Total | 431 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroOneFourCommerceDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 333 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroOneFourCommerceDriveMember |  |  |
23028 Commerce Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Farmington Hills, MI |  |  |
Initial Cost of Land | 98 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroTwoEightCommerceDriveMember |  |  |
Building and Improvements | 507 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroTwoEightCommerceDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 278 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroTwoEightCommerceDriveMember |  |  |
Land | 125 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroTwoEightCommerceDriveMember |  |  |
Building and improvements | 758 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroTwoEightCommerceDriveMember |  |  |
Total | 883 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroTwoEightCommerceDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 704 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroTwoEightCommerceDriveMember |  |  |
23035 Commerce Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Farmington Hills, MI |  |  |
Initial Cost of Land | 71 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroThreeFiveCommerceDriveMember |  |  |
Building and Improvements | 355 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroThreeFiveCommerceDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 237 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroThreeFiveCommerceDriveMember |  |  |
Land | 93 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroThreeFiveCommerceDriveMember |  |  |
Building and improvements | 570 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroThreeFiveCommerceDriveMember |  |  |
Total | 663 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroThreeFiveCommerceDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 526 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroThreeFiveCommerceDriveMember |  |  |
23042 Commerce Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Farmington Hills, MI |  |  |
Initial Cost of Land | 67 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroFourTwoCommerceDriveMember |  |  |
Building and Improvements | 277 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroFourTwoCommerceDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 273 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroFourTwoCommerceDriveMember |  |  |
Land | 89 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroFourTwoCommerceDriveMember |  |  |
Building and improvements | 528 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroFourTwoCommerceDriveMember |  |  |
Total | 617 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroFourTwoCommerceDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 500 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroFourTwoCommerceDriveMember |  |  |
23065 Commerce Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Farmington Hills, MI |  |  |
Initial Cost of Land | 71 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroSixFiveCommerceDriveMember |  |  |
Building and Improvements | 408 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroSixFiveCommerceDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 338 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroSixFiveCommerceDriveMember |  |  |
Land | 93 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroSixFiveCommerceDriveMember |  |  |
Building and improvements | 724 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroSixFiveCommerceDriveMember |  |  |
Total | 817 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroSixFiveCommerceDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 599 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroSixFiveCommerceDriveMember |  |  |
23079 Commerce Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Farmington Hills, MI |  |  |
Initial Cost of Land | 68 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroSevenNineCommerceDriveMember |  |  |
Building and Improvements | 301 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroSevenNineCommerceDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 290 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroSevenNineCommerceDriveMember |  |  |
Land | 79 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroSevenNineCommerceDriveMember |  |  |
Building and improvements | 580 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroSevenNineCommerceDriveMember |  |  |
Total | 659 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroSevenNineCommerceDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 524 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroSevenNineCommerceDriveMember |  |  |
23093 Commerce Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Farmington Hills, MI |  |  |
Initial Cost of Land | 211 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroNineThreeCommerceDriveMember |  |  |
Building and Improvements | 1,024 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroNineThreeCommerceDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,219 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroNineThreeCommerceDriveMember |  |  |
Land | 295 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroNineThreeCommerceDriveMember |  |  |
Building and improvements | 2,159 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroNineThreeCommerceDriveMember |  |  |
Total | 2,454 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroNineThreeCommerceDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,758 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroNineThreeCommerceDriveMember |  |  |
23135 Commerce Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Farmington Hills, MI |  |  |
Initial Cost of Land | 146 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeOneThreeFiveCommerceDriveMember |  |  |
Building and Improvements | 701 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeOneThreeFiveCommerceDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 392 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeOneThreeFiveCommerceDriveMember |  |  |
Land | 158 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeOneThreeFiveCommerceDriveMember |  |  |
Building and improvements | 1,081 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeOneThreeFiveCommerceDriveMember |  |  |
Total | 1,239 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeOneThreeFiveCommerceDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 904 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeOneThreeFiveCommerceDriveMember |  |  |
23163 Commerce Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Farmington Hills, MI |  |  |
Initial Cost of Land | 111 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeOneSixThreeCommerceDriveMember |  |  |
Building and Improvements | 513 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeOneSixThreeCommerceDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 384 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeOneSixThreeCommerceDriveMember |  |  |
Land | 138 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeOneSixThreeCommerceDriveMember |  |  |
Building and improvements | 870 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeOneSixThreeCommerceDriveMember |  |  |
Total | 1,008 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeOneSixThreeCommerceDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 729 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeOneSixThreeCommerceDriveMember |  |  |
23177 Commerce Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Farmington Hills, MI |  |  |
Initial Cost of Land | 175 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeOneSevenSevenCommerceDriveMember |  |  |
Building and Improvements | 1,007 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeOneSevenSevenCommerceDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 611 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeOneSevenSevenCommerceDriveMember |  |  |
Land | 254 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeOneSevenSevenCommerceDriveMember |  |  |
Building and improvements | 1,539 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeOneSevenSevenCommerceDriveMember |  |  |
Total | 1,793 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeOneSevenSevenCommerceDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,313 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeOneSevenSevenCommerceDriveMember |  |  |
23206 Commerce Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Farmington Hills, MI |  |  |
Initial Cost of Land | 125 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeTwoZeroSixCommerceDriveMember |  |  |
Building and Improvements | 531 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeTwoZeroSixCommerceDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 367 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeTwoZeroSixCommerceDriveMember |  |  |
Land | 137 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeTwoZeroSixCommerceDriveMember |  |  |
Building and improvements | 886 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeTwoZeroSixCommerceDriveMember |  |  |
Total | 1,023 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeTwoZeroSixCommerceDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 730 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeTwoZeroSixCommerceDriveMember |  |  |
23370 Commerce Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Farmington Hills, MI |  |  |
Initial Cost of Land | 59 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeThreeSevenZeroCommerceDriveMember |  |  |
Building and Improvements | 233 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeThreeSevenZeroCommerceDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 174 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeThreeSevenZeroCommerceDriveMember |  |  |
Land | 66 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeThreeSevenZeroCommerceDriveMember |  |  |
Building and improvements | 400 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeThreeSevenZeroCommerceDriveMember |  |  |
Total | 466 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeThreeSevenZeroCommerceDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 374 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeThreeSevenZeroCommerceDriveMember |  |  |
1451 East Lincoln Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Madison Heights, MI |  |  |
Initial Cost of Land | 299 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourFiveOneEastLincolnAvenueMember |  |  |
Building and Improvements | 1,703 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourFiveOneEastLincolnAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (179)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourFiveOneEastLincolnAvenueMember |  |  |
Land | 148 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourFiveOneEastLincolnAvenueMember |  |  |
Building and improvements | 1,675 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourFiveOneEastLincolnAvenueMember |  |  |
Total | 1,823 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourFiveOneEastLincolnAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 864 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourFiveOneEastLincolnAvenueMember |  |  |
4400 Purks Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Auburn Hills, MI |  |  |
Initial Cost of Land | 602 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFourZeroZeroPurksDriveMember |  |  |
Building and Improvements | 3,410 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFourZeroZeroPurksDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 3,300 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFourZeroZeroPurksDriveMember |  |  |
Land | 612 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFourZeroZeroPurksDriveMember |  |  |
Building and improvements | 6,700 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFourZeroZeroPurksDriveMember |  |  |
Total | 7,312 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFourZeroZeroPurksDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 3,042 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFourZeroZeroPurksDriveMember |  |  |
32450 N Avis Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Madison Heights, MI |  |  |
Initial Cost of Land | 281 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoFourFiveZeroNAvisDriveMember |  |  |
Building and Improvements | 1,590 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoFourFiveZeroNAvisDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 541 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoFourFiveZeroNAvisDriveMember |  |  |
Land | 286 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoFourFiveZeroNAvisDriveMember |  |  |
Building and improvements | 2,126 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoFourFiveZeroNAvisDriveMember |  |  |
Total | 2,412 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoFourFiveZeroNAvisDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,047 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoFourFiveZeroNAvisDriveMember |  |  |
12707 Eckles Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Plymouth Township, MI |  |  |
Initial Cost of Land | 255 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenZeroSevenEcklesRoadMember |  |  |
Building and Improvements | 1,445 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenZeroSevenEcklesRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 220 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenZeroSevenEcklesRoadMember |  |  |
Land | 267 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenZeroSevenEcklesRoadMember |  |  |
Building and improvements | 1,653 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenZeroSevenEcklesRoadMember |  |  |
Total | 1,920 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenZeroSevenEcklesRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 729 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenZeroSevenEcklesRoadMember |  |  |
9300-9328 Harrison Rd [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Romulus, MI |  |  |
Initial Cost of Land | 147 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThreeZeroZeroNineThreeTwoEightHarrisonRdMember |  |  |
Building and Improvements | 834 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThreeZeroZeroNineThreeTwoEightHarrisonRdMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 407 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThreeZeroZeroNineThreeTwoEightHarrisonRdMember |  |  |
Land | 159 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThreeZeroZeroNineThreeTwoEightHarrisonRdMember |  |  |
Building and improvements | 1,229 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThreeZeroZeroNineThreeTwoEightHarrisonRdMember |  |  |
Total | 1,388 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThreeZeroZeroNineThreeTwoEightHarrisonRdMember |  |  |
Accumulated depreciation 12/31/2012 | 541 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThreeZeroZeroNineThreeTwoEightHarrisonRdMember |  |  |
9330-9358 Harrison Rd [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Romulus, MI |  |  |
Initial Cost of Land | 81 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThreeThreeZeroNineThreeFiveEightHarrisonRdMember |  |  |
Building and Improvements | 456 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThreeThreeZeroNineThreeFiveEightHarrisonRdMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 255 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThreeThreeZeroNineThreeFiveEightHarrisonRdMember |  |  |
Land | 89 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThreeThreeZeroNineThreeFiveEightHarrisonRdMember |  |  |
Building and improvements | 703 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThreeThreeZeroNineThreeFiveEightHarrisonRdMember |  |  |
Total | 792 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThreeThreeZeroNineThreeFiveEightHarrisonRdMember |  |  |
Accumulated depreciation 12/31/2012 | 287 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThreeThreeZeroNineThreeFiveEightHarrisonRdMember |  |  |
28420-28448 Highland Rd [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Romulus, MI |  |  |
Initial Cost of Land | 143 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourTwoZeroTwoEightFourFourEightHighlandRdMember |  |  |
Building and Improvements | 809 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourTwoZeroTwoEightFourFourEightHighlandRdMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 753 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourTwoZeroTwoEightFourFourEightHighlandRdMember |  |  |
Land | 154 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourTwoZeroTwoEightFourFourEightHighlandRdMember |  |  |
Building and improvements | 1,551 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourTwoZeroTwoEightFourFourEightHighlandRdMember |  |  |
Total | 1,705 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourTwoZeroTwoEightFourFourEightHighlandRdMember |  |  |
Accumulated depreciation 12/31/2012 | 529 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourTwoZeroTwoEightFourFourEightHighlandRdMember |  |  |
28450-28478 Highland Rd [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Romulus, MI |  |  |
Initial Cost of Land | 81 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourFiveZeroTwoEightFourSevenEightHighlandRdMember |  |  |
Building and Improvements | 461 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourFiveZeroTwoEightFourSevenEightHighlandRdMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 457 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourFiveZeroTwoEightFourSevenEightHighlandRdMember |  |  |
Land | 90 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourFiveZeroTwoEightFourSevenEightHighlandRdMember |  |  |
Building and improvements | 909 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourFiveZeroTwoEightFourSevenEightHighlandRdMember |  |  |
Total | 999 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourFiveZeroTwoEightFourSevenEightHighlandRdMember |  |  |
Accumulated depreciation 12/31/2012 | 343 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourFiveZeroTwoEightFourSevenEightHighlandRdMember |  |  |
28421-28449 Highland Rd [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Romulus, MI |  |  |
Initial Cost of Land | 109 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourTwoOneTwoEightFourFourNineHighlandRdMember |  |  |
Building and Improvements | 617 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourTwoOneTwoEightFourFourNineHighlandRdMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 473 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourTwoOneTwoEightFourFourNineHighlandRdMember |  |  |
Land | 119 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourTwoOneTwoEightFourFourNineHighlandRdMember |  |  |
Building and improvements | 1,080 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourTwoOneTwoEightFourFourNineHighlandRdMember |  |  |
Total | 1,199 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourTwoOneTwoEightFourFourNineHighlandRdMember |  |  |
Accumulated depreciation 12/31/2012 | 451 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourTwoOneTwoEightFourFourNineHighlandRdMember |  |  |
28451-28479 Highland Rd [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Romulus, MI |  |  |
Initial Cost of Land | 107 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourFiveOneTwoEightFourSevenNineHighlandRdMember |  |  |
Building and Improvements | 608 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourFiveOneTwoEightFourSevenNineHighlandRdMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 411 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourFiveOneTwoEightFourSevenNineHighlandRdMember |  |  |
Land | 117 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourFiveOneTwoEightFourSevenNineHighlandRdMember |  |  |
Building and improvements | 1,009 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourFiveOneTwoEightFourSevenNineHighlandRdMember |  |  |
Total | 1,126 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourFiveOneTwoEightFourSevenNineHighlandRdMember |  |  |
Accumulated depreciation 12/31/2012 | 396 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourFiveOneTwoEightFourSevenNineHighlandRdMember |  |  |
28825-28909 Highland Rd [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Romulus, MI |  |  |
Initial Cost of Land | 70 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightEightTwoFiveTwoEightNineZeroNineHighlandRdMember |  |  |
Building and Improvements | 395 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightEightTwoFiveTwoEightNineZeroNineHighlandRdMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 396 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightEightTwoFiveTwoEightNineZeroNineHighlandRdMember |  |  |
Land | 78 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightEightTwoFiveTwoEightNineZeroNineHighlandRdMember |  |  |
Building and improvements | 783 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightEightTwoFiveTwoEightNineZeroNineHighlandRdMember |  |  |
Total | 861 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightEightTwoFiveTwoEightNineZeroNineHighlandRdMember |  |  |
Accumulated depreciation 12/31/2012 | 307 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightEightTwoFiveTwoEightNineZeroNineHighlandRdMember |  |  |
28933-29017 Highland Rd [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Romulus, MI |  |  |
Initial Cost of Land | 112 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightNineThreeThreeTwoNineZeroOneSevenHighlandRdMember |  |  |
Building and Improvements | 634 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightNineThreeThreeTwoNineZeroOneSevenHighlandRdMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 599 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightNineThreeThreeTwoNineZeroOneSevenHighlandRdMember |  |  |
Land | 122 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightNineThreeThreeTwoNineZeroOneSevenHighlandRdMember |  |  |
Building and improvements | 1,223 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightNineThreeThreeTwoNineZeroOneSevenHighlandRdMember |  |  |
Total | 1,345 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightNineThreeThreeTwoNineZeroOneSevenHighlandRdMember |  |  |
Accumulated depreciation 12/31/2012 | 434 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightNineThreeThreeTwoNineZeroOneSevenHighlandRdMember |  |  |
28824-28908 Highland Rd [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Romulus, MI |  |  |
Initial Cost of Land | 134 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightEightTwoFourTwoEightNineZeroEightHighlandRdMember |  |  |
Building and Improvements | 760 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightEightTwoFourTwoEightNineZeroEightHighlandRdMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 577 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightEightTwoFourTwoEightNineZeroEightHighlandRdMember |  |  |
Land | 145 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightEightTwoFourTwoEightNineZeroEightHighlandRdMember |  |  |
Building and improvements | 1,326 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightEightTwoFourTwoEightNineZeroEightHighlandRdMember |  |  |
Total | 1,471 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightEightTwoFourTwoEightNineZeroEightHighlandRdMember |  |  |
Accumulated depreciation 12/31/2012 | 525 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightEightTwoFourTwoEightNineZeroEightHighlandRdMember |  |  |
28932-29016 Highland Rd [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Romulus, MI |  |  |
Initial Cost of Land | 123 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightNineThreeTwoTwoNineZeroOneSixHighlandRdMember |  |  |
Building and Improvements | 694 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightNineThreeTwoTwoNineZeroOneSixHighlandRdMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 582 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightNineThreeTwoTwoNineZeroOneSixHighlandRdMember |  |  |
Land | 133 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightNineThreeTwoTwoNineZeroOneSixHighlandRdMember |  |  |
Building and improvements | 1,266 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightNineThreeTwoTwoNineZeroOneSixHighlandRdMember |  |  |
Total | 1,399 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightNineThreeTwoTwoNineZeroOneSixHighlandRdMember |  |  |
Accumulated depreciation 12/31/2012 | 486 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightNineThreeTwoTwoNineZeroOneSixHighlandRdMember |  |  |
9710-9734 Harrison Rd [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Romulus, MI |  |  |
Initial Cost of Land | 125 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSevenOneZeroNineSevenThreeFourHarrisonRdMember |  |  |
Building and Improvements | 706 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSevenOneZeroNineSevenThreeFourHarrisonRdMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 432 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSevenOneZeroNineSevenThreeFourHarrisonRdMember |  |  |
Land | 135 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSevenOneZeroNineSevenThreeFourHarrisonRdMember |  |  |
Building and improvements | 1,128 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSevenOneZeroNineSevenThreeFourHarrisonRdMember |  |  |
Total | 1,263 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSevenOneZeroNineSevenThreeFourHarrisonRdMember |  |  |
Accumulated depreciation 12/31/2012 | 474 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSevenOneZeroNineSevenThreeFourHarrisonRdMember |  |  |
Nine Seven Four Zero Nine Seven Seven Two Harrison Rd [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Romulus, MI |  |  |
Initial Cost of Land | 132 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSevenFourZeroNineSevenSevenTwoHarrisonRdMember |  |  |
Building and Improvements | 749 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSevenFourZeroNineSevenSevenTwoHarrisonRdMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 401 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSevenFourZeroNineSevenSevenTwoHarrisonRdMember |  |  |
Land | 143 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSevenFourZeroNineSevenSevenTwoHarrisonRdMember |  |  |
Building and improvements | 1,139 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSevenFourZeroNineSevenSevenTwoHarrisonRdMember |  |  |
Total | 1,282 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSevenFourZeroNineSevenSevenTwoHarrisonRdMember |  |  |
Accumulated depreciation 12/31/2012 | 492 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSevenFourZeroNineSevenSevenTwoHarrisonRdMember |  |  |
9840-9868 Harrison Rd [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Romulus, MI |  |  |
Initial Cost of Land | 144 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightFourZeroNineEightSixEightHarrisonRdMember |  |  |
Building and Improvements | 815 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightFourZeroNineEightSixEightHarrisonRdMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 296 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightFourZeroNineEightSixEightHarrisonRdMember |  |  |
Land | 155 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightFourZeroNineEightSixEightHarrisonRdMember |  |  |
Building and improvements | 1,100 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightFourZeroNineEightSixEightHarrisonRdMember |  |  |
Total | 1,255 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightFourZeroNineEightSixEightHarrisonRdMember |  |  |
Accumulated depreciation 12/31/2012 | 452 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightFourZeroNineEightSixEightHarrisonRdMember |  |  |
9800-9824 Harrison Rd [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Romulus, MI |  |  |
Initial Cost of Land | 117 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightZeroZeroNineEightTwoFourHarrisonRdMember |  |  |
Building and Improvements | 664 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightZeroZeroNineEightTwoFourHarrisonRdMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 362 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightZeroZeroNineEightTwoFourHarrisonRdMember |  |  |
Land | 127 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightZeroZeroNineEightTwoFourHarrisonRdMember |  |  |
Building and improvements | 1,016 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightZeroZeroNineEightTwoFourHarrisonRdMember |  |  |
Total | 1,143 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightZeroZeroNineEightTwoFourHarrisonRdMember |  |  |
Accumulated depreciation 12/31/2012 | 401 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightZeroZeroNineEightTwoFourHarrisonRdMember |  |  |
29265-29285 Airport Dr [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Romulus, MI |  |  |
Initial Cost of Land | 140 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineTwoSixFiveTwoNineTwoEightFiveAirportDrMember |  |  |
Building and Improvements | 794 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineTwoSixFiveTwoNineTwoEightFiveAirportDrMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 263 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineTwoSixFiveTwoNineTwoEightFiveAirportDrMember |  |  |
Land | 151 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineTwoSixFiveTwoNineTwoEightFiveAirportDrMember |  |  |
Building and improvements | 1,046 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineTwoSixFiveTwoNineTwoEightFiveAirportDrMember |  |  |
Total | 1,197 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineTwoSixFiveTwoNineTwoEightFiveAirportDrMember |  |  |
Accumulated depreciation 12/31/2012 | 462 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineTwoSixFiveTwoNineTwoEightFiveAirportDrMember |  |  |
29185-29225 Airport Dr [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Romulus, MI |  |  |
Initial Cost of Land | 140 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineOneEightFiveTwoNineTwoTwoFiveAirportDrMember |  |  |
Building and Improvements | 792 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineOneEightFiveTwoNineTwoTwoFiveAirportDrMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 514 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineOneEightFiveTwoNineTwoTwoFiveAirportDrMember |  |  |
Land | 151 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineOneEightFiveTwoNineTwoTwoFiveAirportDrMember |  |  |
Building and improvements | 1,295 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineOneEightFiveTwoNineTwoTwoFiveAirportDrMember |  |  |
Total | 1,446 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineOneEightFiveTwoNineTwoTwoFiveAirportDrMember |  |  |
Accumulated depreciation 12/31/2012 | 580 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineOneEightFiveTwoNineTwoTwoFiveAirportDrMember |  |  |
29149-29165 Airport Dr [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Romulus, MI |  |  |
Initial Cost of Land | 216 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineOneFourNineTwoNineOneSixFiveAirportDrMember |  |  |
Building and Improvements | 1,225 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineOneFourNineTwoNineOneSixFiveAirportDrMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 305 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineOneFourNineTwoNineOneSixFiveAirportDrMember |  |  |
Land | 231 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineOneFourNineTwoNineOneSixFiveAirportDrMember |  |  |
Building and improvements | 1,515 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineOneFourNineTwoNineOneSixFiveAirportDrMember |  |  |
Total | 1,746 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineOneFourNineTwoNineOneSixFiveAirportDrMember |  |  |
Accumulated depreciation 12/31/2012 | 674 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineOneFourNineTwoNineOneSixFiveAirportDrMember |  |  |
29101-29115 Airport Dr [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Romulus, MI |  |  |
Initial Cost of Land | 130 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineOneZeroOneTwoNineOneOneFiveAirportDrMember |  |  |
Building and Improvements | 738 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineOneZeroOneTwoNineOneOneFiveAirportDrMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 285 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineOneZeroOneTwoNineOneOneFiveAirportDrMember |  |  |
Land | 141 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineOneZeroOneTwoNineOneOneFiveAirportDrMember |  |  |
Building and improvements | 1,012 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineOneZeroOneTwoNineOneOneFiveAirportDrMember |  |  |
Total | 1,153 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineOneZeroOneTwoNineOneOneFiveAirportDrMember |  |  |
Accumulated depreciation 12/31/2012 | 472 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineOneZeroOneTwoNineOneOneFiveAirportDrMember |  |  |
29031-29045 Airport Dr [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Romulus, MI |  |  |
Initial Cost of Land | 124 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineZeroThreeOneTwoNineZeroFourFiveAirportDrMember |  |  |
Building and Improvements | 704 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineZeroThreeOneTwoNineZeroFourFiveAirportDrMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 215 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineZeroThreeOneTwoNineZeroFourFiveAirportDrMember |  |  |
Land | 134 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineZeroThreeOneTwoNineZeroFourFiveAirportDrMember |  |  |
Building and improvements | 909 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineZeroThreeOneTwoNineZeroFourFiveAirportDrMember |  |  |
Total | 1,043 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineZeroThreeOneTwoNineZeroFourFiveAirportDrMember |  |  |
Accumulated depreciation 12/31/2012 | 374 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineZeroThreeOneTwoNineZeroFourFiveAirportDrMember |  |  |
29050-29062 Airport Dr [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Romulus, MI |  |  |
Initial Cost of Land | 127 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineZeroFiveZeroTwoNineZeroSixTwoAirportDrMember |  |  |
Building and Improvements | 718 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineZeroFiveZeroTwoNineZeroSixTwoAirportDrMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 218 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineZeroFiveZeroTwoNineZeroSixTwoAirportDrMember |  |  |
Land | 137 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineZeroFiveZeroTwoNineZeroSixTwoAirportDrMember |  |  |
Building and improvements | 926 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineZeroFiveZeroTwoNineZeroSixTwoAirportDrMember |  |  |
Total | 1,063 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineZeroFiveZeroTwoNineZeroSixTwoAirportDrMember |  |  |
Accumulated depreciation 12/31/2012 | 385 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineZeroFiveZeroTwoNineZeroSixTwoAirportDrMember |  |  |
29120-29134 Airport Dr [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Romulus, MI |  |  |
Initial Cost of Land | 161 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineOneTwoZeroTwoNineOneThreeFourAirportDrMember |  |  |
Building and Improvements | 912 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineOneTwoZeroTwoNineOneThreeFourAirportDrMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 522 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineOneTwoZeroTwoNineOneThreeFourAirportDrMember |  |  |
Land | 173 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineOneTwoZeroTwoNineOneThreeFourAirportDrMember |  |  |
Building and improvements | 1,422 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineOneTwoZeroTwoNineOneThreeFourAirportDrMember |  |  |
Total | 1,595 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineOneTwoZeroTwoNineOneThreeFourAirportDrMember |  |  |
Accumulated depreciation 12/31/2012 | 569 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineOneTwoZeroTwoNineOneThreeFourAirportDrMember |  |  |
29200-29214 Airport Dr [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Romulus, MI |  |  |
Initial Cost of Land | 170 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineTwoZeroZeroTwoNineTwoOneFourAirportDrMember |  |  |
Building and Improvements | 963 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineTwoZeroZeroTwoNineTwoOneFourAirportDrMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 310 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineTwoZeroZeroTwoNineTwoOneFourAirportDrMember |  |  |
Land | 182 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineTwoZeroZeroTwoNineTwoOneFourAirportDrMember |  |  |
Building and improvements | 1,261 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineTwoZeroZeroTwoNineTwoOneFourAirportDrMember |  |  |
Total | 1,443 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineTwoZeroZeroTwoNineTwoOneFourAirportDrMember |  |  |
Accumulated depreciation 12/31/2012 | 465 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineTwoZeroZeroTwoNineTwoOneFourAirportDrMember |  |  |
9301-9339 Middlebelt Rd [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Romulus, MI |  |  |
Initial Cost of Land | 124 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThreeZeroOneNineThreeThreeNineMiddlebeltRdMember |  |  |
Building and Improvements | 703 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThreeZeroOneNineThreeThreeNineMiddlebeltRdMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 444 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThreeZeroOneNineThreeThreeNineMiddlebeltRdMember |  |  |
Land | 130 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThreeZeroOneNineThreeThreeNineMiddlebeltRdMember |  |  |
Building and improvements | 1,141 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThreeZeroOneNineThreeThreeNineMiddlebeltRdMember |  |  |
Total | 1,271 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThreeZeroOneNineThreeThreeNineMiddlebeltRdMember |  |  |
Accumulated depreciation 12/31/2012 | 510 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThreeZeroOneNineThreeThreeNineMiddlebeltRdMember |  |  |
32975 Capitol Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Livonia, MI |  |  |
Initial Cost of Land | 135 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoNineSevenFiveCapitolAvenueMember |  |  |
Building and Improvements | 748 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoNineSevenFiveCapitolAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (166)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoNineSevenFiveCapitolAvenueMember |  |  |
Land | 77 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoNineSevenFiveCapitolAvenueMember |  |  |
Building and improvements | 640 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoNineSevenFiveCapitolAvenueMember |  |  |
Total | 717 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoNineSevenFiveCapitolAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 313 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoNineSevenFiveCapitolAvenueMember |  |  |
32920 Capitol Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Livonia, MI |  |  |
Initial Cost of Land | 76 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoNineTwoZeroCapitolAvenueMember |  |  |
Building and Improvements | 422 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoNineTwoZeroCapitolAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (62)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoNineTwoZeroCapitolAvenueMember |  |  |
Land | 27 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoNineTwoZeroCapitolAvenueMember |  |  |
Building and improvements | 409 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoNineTwoZeroCapitolAvenueMember |  |  |
Total | 436 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoNineTwoZeroCapitolAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 217 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoNineTwoZeroCapitolAvenueMember |  |  |
11923 Brookfield Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Livonia, MI |  |  |
Initial Cost of Land | 120 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneNineTwoThreeBrookfieldAvenueMember |  |  |
Building and Improvements | 665 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneNineTwoThreeBrookfieldAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (324)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneNineTwoThreeBrookfieldAvenueMember |  |  |
Land | 32 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneNineTwoThreeBrookfieldAvenueMember |  |  |
Building and improvements | 429 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneNineTwoThreeBrookfieldAvenueMember |  |  |
Total | 461 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneNineTwoThreeBrookfieldAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 294 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneNineTwoThreeBrookfieldAvenueMember |  |  |
450 Robbins Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Troy, MI |  |  |
Initial Cost of Land | 166 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveZeroRobbinsDriveMember |  |  |
Building and Improvements | 920 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveZeroRobbinsDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 231 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveZeroRobbinsDriveMember |  |  |
Land | 178 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveZeroRobbinsDriveMember |  |  |
Building and improvements | 1,139 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveZeroRobbinsDriveMember |  |  |
Total | 1,317 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveZeroRobbinsDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 467 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveZeroRobbinsDriveMember |  |  |
12886 Westmore Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Livonia, MI |  |  |
Initial Cost of Land | 190 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoEightEightSixWestmoreAvenueMember |  |  |
Building and Improvements | 1,050 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoEightEightSixWestmoreAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (351)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoEightEightSixWestmoreAvenueMember |  |  |
Land | 86 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoEightEightSixWestmoreAvenueMember |  |  |
Building and improvements | 803 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoEightEightSixWestmoreAvenueMember |  |  |
Total | 889 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoEightEightSixWestmoreAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 442 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoEightEightSixWestmoreAvenueMember |  |  |
47711 Clipper Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Plymouth Township, MI |  |  |
Initial Cost of Land | 539 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenSevenOneOneClipperStreetMember |  |  |
Building and Improvements | 2,983 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenSevenOneOneClipperStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 359 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenSevenOneOneClipperStreetMember |  |  |
Land | 575 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenSevenOneOneClipperStreetMember |  |  |
Building and improvements | 3,306 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenSevenOneOneClipperStreetMember |  |  |
Total | 3,881 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenSevenOneOneClipperStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 1,338 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenSevenOneOneClipperStreetMember |  |  |
32975 Industrial Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Livonia, MI |  |  |
Initial Cost of Land | 160 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoNineSevenFiveIndustrialRoadMember |  |  |
Building and Improvements | 887 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoNineSevenFiveIndustrialRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (191)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoNineSevenFiveIndustrialRoadMember |  |  |
Land | 92 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoNineSevenFiveIndustrialRoadMember |  |  |
Building and improvements | 764 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoNineSevenFiveIndustrialRoadMember |  |  |
Total | 856 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoNineSevenFiveIndustrialRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 379 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoNineSevenFiveIndustrialRoadMember |  |  |
32985 Industrial Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Livonia, MI |  |  |
Initial Cost of Land | 137 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoNineEightFiveIndustrialRoadMember |  |  |
Building and Improvements | 761 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoNineEightFiveIndustrialRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (329)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoNineEightFiveIndustrialRoadMember |  |  |
Land | 46 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoNineEightFiveIndustrialRoadMember |  |  |
Building and improvements | 523 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoNineEightFiveIndustrialRoadMember |  |  |
Total | 569 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoNineEightFiveIndustrialRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 319 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoNineEightFiveIndustrialRoadMember |  |  |
32995 Industrial Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Livonia, MI |  |  |
Initial Cost of Land | 160 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoNineNineFiveIndustrialRoadMember |  |  |
Building and Improvements | 887 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoNineNineFiveIndustrialRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (409)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoNineNineFiveIndustrialRoadMember |  |  |
Land | 53 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoNineNineFiveIndustrialRoadMember |  |  |
Building and improvements | 585 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoNineNineFiveIndustrialRoadMember |  |  |
Total | 638 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoNineNineFiveIndustrialRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 363 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoNineNineFiveIndustrialRoadMember |  |  |
12874 Westmore Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Livonia, MI |  |  |
Initial Cost of Land | 137 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoEightSevenFourWestmoreAvenueMember |  |  |
Building and Improvements | 761 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoEightSevenFourWestmoreAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (302)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoEightSevenFourWestmoreAvenueMember |  |  |
Land | 58 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoEightSevenFourWestmoreAvenueMember |  |  |
Building and improvements | 538 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoEightSevenFourWestmoreAvenueMember |  |  |
Total | 596 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoEightSevenFourWestmoreAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 301 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoEightSevenFourWestmoreAvenueMember |  |  |
1775 Bellingham [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Troy, MI |  |  |
Initial Cost of Land | 344 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenSevenFiveBellinghamMember |  |  |
Building and Improvements | 1,902 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenSevenFiveBellinghamMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 329 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenSevenFiveBellinghamMember |  |  |
Land | 367 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenSevenFiveBellinghamMember |  |  |
Building and improvements | 2,208 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenSevenFiveBellinghamMember |  |  |
Total | 2,575 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenSevenFiveBellinghamMember |  |  |
Accumulated depreciation 12/31/2012 | 893 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenSevenFiveBellinghamMember |  |  |
1785 East Maple [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Troy, MI |  |  |
Initial Cost of Land | 92 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenEightFiveEastMapleMember |  |  |
Building and Improvements | 507 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenEightFiveEastMapleMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 200 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenEightFiveEastMapleMember |  |  |
Land | 98 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenEightFiveEastMapleMember |  |  |
Building and improvements | 701 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenEightFiveEastMapleMember |  |  |
Total | 799 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenEightFiveEastMapleMember |  |  |
Accumulated depreciation 12/31/2012 | 257 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenEightFiveEastMapleMember |  |  |
980 Chicago [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Troy, MI |  |  |
Initial Cost of Land | 206 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightZeroChicagoMember |  |  |
Building and Improvements | 1,141 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightZeroChicagoMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 328 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightZeroChicagoMember |  |  |
Land | 220 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightZeroChicagoMember |  |  |
Building and improvements | 1,455 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightZeroChicagoMember |  |  |
Total | 1,675 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightZeroChicagoMember |  |  |
Accumulated depreciation 12/31/2012 | 537 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightZeroChicagoMember |  |  |
1885 Enterprise Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Rochester Hills, MI |  |  |
Initial Cost of Land | 209 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightEightFiveEnterpriseDriveMember |  |  |
Building and Improvements | 1,158 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightEightFiveEnterpriseDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 544 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightEightFiveEnterpriseDriveMember |  |  |
Land | 223 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightEightFiveEnterpriseDriveMember |  |  |
Building and improvements | 1,688 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightEightFiveEnterpriseDriveMember |  |  |
Total | 1,911 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightEightFiveEnterpriseDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 561 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightEightFiveEnterpriseDriveMember |  |  |
1935-55 Enterprise Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Rochester Hills, MI |  |  |
Initial Cost of Land | 1,285 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineThreeFiveAndFiveFiveEnterpriseDriveMember |  |  |
Building and Improvements | 7,144 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineThreeFiveAndFiveFiveEnterpriseDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 943 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineThreeFiveAndFiveFiveEnterpriseDriveMember |  |  |
Land | 1,371 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineThreeFiveAndFiveFiveEnterpriseDriveMember |  |  |
Building and improvements | 8,001 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineThreeFiveAndFiveFiveEnterpriseDriveMember |  |  |
Total | 9,372 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineThreeFiveAndFiveFiveEnterpriseDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 3,229 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineThreeFiveAndFiveFiveEnterpriseDriveMember |  |  |
5500 Enterprise Court [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Warren, MI |  |  |
Initial Cost of Land | 675 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveZeroZeroEnterpriseCourtMember |  |  |
Building and Improvements | 3,737 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveZeroZeroEnterpriseCourtMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 680 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveZeroZeroEnterpriseCourtMember |  |  |
Land | 721 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveZeroZeroEnterpriseCourtMember |  |  |
Building and improvements | 4,371 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveZeroZeroEnterpriseCourtMember |  |  |
Total | 5,092 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveZeroZeroEnterpriseCourtMember |  |  |
Accumulated depreciation 12/31/2012 | 1,751 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveZeroZeroEnterpriseCourtMember |  |  |
750 Chicago Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Troy, MI |  |  |
Initial Cost of Land | 323 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFiveZeroChicagoRoadMember |  |  |
Building and Improvements | 1,790 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFiveZeroChicagoRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 385 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFiveZeroChicagoRoadMember |  |  |
Land | 345 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFiveZeroChicagoRoadMember |  |  |
Building and improvements | 2,153 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFiveZeroChicagoRoadMember |  |  |
Total | 2,498 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFiveZeroChicagoRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 880 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFiveZeroChicagoRoadMember |  |  |
800 Chicago Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Troy, MI |  |  |
Initial Cost of Land | 283 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightZeroZeroChicagoRoadMember |  |  |
Building and Improvements | 1,567 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightZeroZeroChicagoRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 370 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightZeroZeroChicagoRoadMember |  |  |
Land | 302 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightZeroZeroChicagoRoadMember |  |  |
Building and improvements | 1,918 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightZeroZeroChicagoRoadMember |  |  |
Total | 2,220 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightZeroZeroChicagoRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 763 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightZeroZeroChicagoRoadMember |  |  |
850 Chicago Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Troy, MI |  |  |
Initial Cost of Land | 183 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightFiveZeroChicagoRoadMember |  |  |
Building and Improvements | 1,016 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightFiveZeroChicagoRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 218 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightFiveZeroChicagoRoadMember |  |  |
Land | 196 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightFiveZeroChicagoRoadMember |  |  |
Building and improvements | 1,221 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightFiveZeroChicagoRoadMember |  |  |
Total | 1,417 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightFiveZeroChicagoRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 493 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightFiveZeroChicagoRoadMember |  |  |
1100 East Mandoline Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Madison Heights, MI |  |  |
Initial Cost of Land | 888 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneZeroZeroEastMandolineRoadMember |  |  |
Building and Improvements | 4,915 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneZeroZeroEastMandolineRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (1,257)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneZeroZeroEastMandolineRoadMember |  |  |
Land | 332 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneZeroZeroEastMandolineRoadMember |  |  |
Building and improvements | 4,214 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneZeroZeroEastMandolineRoadMember |  |  |
Total | 4,546 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneZeroZeroEastMandolineRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 2,372 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneZeroZeroEastMandolineRoadMember |  |  |
One Zero Eight Zero One One Two Zero One One Eight Zero John Papalas Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Lincoln Park, MI |  |  |
Initial Cost of Land | 366 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroEightZeroOneOneTwoZeroOneOneEightZeroJohnPapalasDriveMember |  |  |
Building and Improvements | 3,241 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroEightZeroOneOneTwoZeroOneOneEightZeroJohnPapalasDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 366 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroEightZeroOneOneTwoZeroOneOneEightZeroJohnPapalasDriveMember |  |  |
Land | 297 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroEightZeroOneOneTwoZeroOneOneEightZeroJohnPapalasDriveMember |  |  |
Building and improvements | 3,676 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroEightZeroOneOneTwoZeroOneOneEightZeroJohnPapalasDriveMember |  |  |
Total | 3,973 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroEightZeroOneOneTwoZeroOneOneEightZeroJohnPapalasDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,918 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroEightZeroOneOneTwoZeroOneOneEightZeroJohnPapalasDriveMember |  |  |
4872 S. Lapeer Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Lake Orion Twsp, MI |  |  |
Initial Cost of Land | 1,342 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourEightSevenTwoSLapeerRoadMember |  |  |
Building and Improvements | 5,441 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourEightSevenTwoSLapeerRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,208 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourEightSevenTwoSLapeerRoadMember |  |  |
Land | 1,412 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourEightSevenTwoSLapeerRoadMember |  |  |
Building and improvements | 6,579 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourEightSevenTwoSLapeerRoadMember |  |  |
Total | 7,991 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourEightSevenTwoSLapeerRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 2,609 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourEightSevenTwoSLapeerRoadMember |  |  |
22701 Trolley Industrial [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Taylor, MI |  |  |
Initial Cost of Land | 795 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoTwoSevenZeroOneTrolleyIndustrialMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 7,435 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoTwoSevenZeroOneTrolleyIndustrialMember |  |  |
Land | 849 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoTwoSevenZeroOneTrolleyIndustrialMember |  |  |
Building and improvements | 7,381 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoTwoSevenZeroOneTrolleyIndustrialMember |  |  |
Total | 8,230 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoTwoSevenZeroOneTrolleyIndustrialMember |  |  |
Accumulated depreciation 12/31/2012 | 2,475 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoTwoSevenZeroOneTrolleyIndustrialMember |  |  |
1400 Allen Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Troy, MI |  |  |
Initial Cost of Land | 209 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourZeroZeroAllenDriveMember |  |  |
Building and Improvements | 1,154 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourZeroZeroAllenDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 223 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourZeroZeroAllenDriveMember |  |  |
Land | 212 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourZeroZeroAllenDriveMember |  |  |
Building and improvements | 1,374 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourZeroZeroAllenDriveMember |  |  |
Total | 1,586 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourZeroZeroAllenDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 455 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourZeroZeroAllenDriveMember |  |  |
1408 Allen Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Troy, MI |  |  |
Initial Cost of Land | 151 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourZeroEightAllenDriveMember |  |  |
Building and Improvements | 834 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourZeroEightAllenDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 121 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourZeroEightAllenDriveMember |  |  |
Land | 153 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourZeroEightAllenDriveMember |  |  |
Building and improvements | 953 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourZeroEightAllenDriveMember |  |  |
Total | 1,106 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourZeroEightAllenDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 318 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourZeroEightAllenDriveMember |  |  |
32505 Industrial Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Madison Heights, MI |  |  |
Initial Cost of Land | 345 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoFiveZeroFiveIndustrialDriveMember |  |  |
Building and Improvements | 1,910 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoFiveZeroFiveIndustrialDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 107 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoFiveZeroFiveIndustrialDriveMember |  |  |
Land | 351 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoFiveZeroFiveIndustrialDriveMember |  |  |
Building and improvements | 2,011 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoFiveZeroFiveIndustrialDriveMember |  |  |
Total | 2,362 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoFiveZeroFiveIndustrialDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 694 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoFiveZeroFiveIndustrialDriveMember |  |  |
One Seven Nine Nine to One Eight Five Five Northfield Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Rochester Hills, MI |  |  |
Initial Cost of Land | 481 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenNineNinetoOneEightFiveFiveNorthfieldDriveMember |  |  |
Building and Improvements | 2,665 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenNineNinetoOneEightFiveFiveNorthfieldDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 367 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenNineNinetoOneEightFiveFiveNorthfieldDriveMember |  |  |
Land | 490 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenNineNinetoOneEightFiveFiveNorthfieldDriveMember |  |  |
Building and improvements | 3,023 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenNineNinetoOneEightFiveFiveNorthfieldDriveMember |  |  |
Total | 3,513 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenNineNinetoOneEightFiveFiveNorthfieldDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,060 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenNineNinetoOneEightFiveFiveNorthfieldDriveMember |  |  |
28435 Automation Blvd [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Wixom, MI |  |  |
Initial Cost of Land | 621 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourThreeFiveAutomationBlvdMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 3,664 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourThreeFiveAutomationBlvdMember |  |  |
Land | 628 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourThreeFiveAutomationBlvdMember |  |  |
Building and improvements | 3,657 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourThreeFiveAutomationBlvdMember |  |  |
Total | 4,285 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourThreeFiveAutomationBlvdMember |  |  |
Accumulated depreciation 12/31/2012 | 919 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightFourThreeFiveAutomationBlvdMember |  |  |
32200 N Avis Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Madison Heights, MI |  |  |
Initial Cost of Land | 503 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoTwoZeroZeroNAvisDriveMember |  |  |
Building and Improvements | 3,367 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoTwoZeroZeroNAvisDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (1,446)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoTwoZeroZeroNAvisDriveMember |  |  |
Land | 195 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoTwoZeroZeroNAvisDriveMember |  |  |
Building and improvements | 2,229 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoTwoZeroZeroNAvisDriveMember |  |  |
Total | 2,424 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoTwoZeroZeroNAvisDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 867 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoTwoZeroZeroNAvisDriveMember |  |  |
100 Kay Industrial Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Orion Township, MI |  |  |
Initial Cost of Land | 677 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroZeroKayIndustrialDriveMember |  |  |
Building and Improvements | 2,018 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroZeroKayIndustrialDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 171 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroZeroKayIndustrialDriveMember |  |  |
Land | 685 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroZeroKayIndustrialDriveMember |  |  |
Building and improvements | 2,181 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroZeroKayIndustrialDriveMember |  |  |
Total | 2,866 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroZeroKayIndustrialDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 860 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroZeroKayIndustrialDriveMember |  |  |
11800 Sears Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Livonia, MI |  |  |
Initial Cost of Land | 693 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneEightZeroZeroSearsDriveMember |  |  |
Building and Improvements | 1,507 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneEightZeroZeroSearsDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,212 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneEightZeroZeroSearsDriveMember |  |  |
Land | 476 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneEightZeroZeroSearsDriveMember |  |  |
Building and improvements | 2,936 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneEightZeroZeroSearsDriveMember |  |  |
Total | 3,412 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneEightZeroZeroSearsDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,451 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneEightZeroZeroSearsDriveMember |  |  |
1099 Chicago Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Troy, MI |  |  |
Initial Cost of Land | 1,277 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroNineNineChicagoRoadMember |  |  |
Building and Improvements | 1,332 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroNineNineChicagoRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (1,275)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroNineNineChicagoRoadMember |  |  |
Land | 303 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroNineNineChicagoRoadMember |  |  |
Building and improvements | 1,031 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroNineNineChicagoRoadMember |  |  |
Total | 1,334 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroNineNineChicagoRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 294 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroNineNineChicagoRoadMember |  |  |
42555 Merrill Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Sterling Heights, MI |  |  |
Initial Cost of Land | 1,080 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourTwoFiveFiveFiveMerrillRoadMember |  |  |
Building and Improvements | 2,300 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourTwoFiveFiveFiveMerrillRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 3,487 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourTwoFiveFiveFiveMerrillRoadMember |  |  |
Land | 1,090 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourTwoFiveFiveFiveMerrillRoadMember |  |  |
Building and improvements | 5,777 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourTwoFiveFiveFiveMerrillRoadMember |  |  |
Total | 6,867 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourTwoFiveFiveFiveMerrillRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 1,991 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourTwoFiveFiveFiveMerrillRoadMember |  |  |
200 Northpointe Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Orion Township, MI |  |  |
Initial Cost of Land | 723 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroNorthpointeDriveMember |  |  |
Building and Improvements | 2,063 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroNorthpointeDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 36 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroNorthpointeDriveMember |  |  |
Land | 734 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroNorthpointeDriveMember |  |  |
Building and improvements | 2,088 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroNorthpointeDriveMember |  |  |
Total | 2,822 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroNorthpointeDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 882 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroNorthpointeDriveMember |  |  |
3351 Rauch St [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Houston, TX |  |  |
Initial Cost of Land | 272 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThreeFiveOneRauchStMember |  |  |
Building and Improvements | 1,541 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThreeFiveOneRauchStMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 510 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThreeFiveOneRauchStMember |  |  |
Land | 278 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThreeFiveOneRauchStMember |  |  |
Building and improvements | 2,045 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThreeFiveOneRauchStMember |  |  |
Total | 2,323 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThreeFiveOneRauchStMember |  |  |
Accumulated depreciation 12/31/2012 | 764 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThreeFiveOneRauchStMember |  |  |
3801-3851 Yale St [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Houston, TX |  |  |
Encumbrances |  | 1,977 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeEightZeroOneToThreeEightFiveOneYaleStMember |  |
Initial Cost of Land | 413 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeEightZeroOneToThreeEightFiveOneYaleStMember |  |  |
Building and Improvements | 2,343 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeEightZeroOneToThreeEightFiveOneYaleStMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 419 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeEightZeroOneToThreeEightFiveOneYaleStMember |  |  |
Land | 425 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeEightZeroOneToThreeEightFiveOneYaleStMember |  |  |
Building and improvements | 2,750 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeEightZeroOneToThreeEightFiveOneYaleStMember |  |  |
Total | 3,175 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeEightZeroOneToThreeEightFiveOneYaleStMember |  |  |
Accumulated depreciation 12/31/2012 | 1,158 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeEightZeroOneToThreeEightFiveOneYaleStMember |  |  |
3337-3347 Rauch Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Houston, TX |  |  |
Initial Cost of Land | 227 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThreeThreeSevenAndThreeThreeFourSevenRauchStreetMember |  |  |
Building and Improvements | 1,287 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThreeThreeSevenAndThreeThreeFourSevenRauchStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 454 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThreeThreeSevenAndThreeThreeFourSevenRauchStreetMember |  |  |
Land | 233 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThreeThreeSevenAndThreeThreeFourSevenRauchStreetMember |  |  |
Building and improvements | 1,735 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThreeThreeSevenAndThreeThreeFourSevenRauchStreetMember |  |  |
Total | 1,968 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThreeThreeSevenAndThreeThreeFourSevenRauchStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 669 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThreeThreeSevenAndThreeThreeFourSevenRauchStreetMember |  |  |
8505 N Loop East [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Houston, TX |  |  |
Encumbrances |  | 1,630 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightFiveZeroFiveNLoopEastMember |  |
Initial Cost of Land | 439 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightFiveZeroFiveNLoopEastMember |  |  |
Building and Improvements | 2,489 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightFiveZeroFiveNLoopEastMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 626 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightFiveZeroFiveNLoopEastMember |  |  |
Land | 449 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightFiveZeroFiveNLoopEastMember |  |  |
Building and improvements | 3,105 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightFiveZeroFiveNLoopEastMember |  |  |
Total | 3,554 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightFiveZeroFiveNLoopEastMember |  |  |
Accumulated depreciation 12/31/2012 | 1,271 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightFiveZeroFiveNLoopEastMember |  |  |
4749-4799 Eastpark Dr [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Houston, TX |  |  |
Encumbrances |  | 2,409 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenFourNineAndFourSevenNineNineEastparkDrMember |  |
Initial Cost of Land | 594 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenFourNineAndFourSevenNineNineEastparkDrMember |  |  |
Building and Improvements | 3,368 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenFourNineAndFourSevenNineNineEastparkDrMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,290 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenFourNineAndFourSevenNineNineEastparkDrMember |  |  |
Land | 611 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenFourNineAndFourSevenNineNineEastparkDrMember |  |  |
Building and improvements | 4,641 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenFourNineAndFourSevenNineNineEastparkDrMember |  |  |
Total | 5,252 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenFourNineAndFourSevenNineNineEastparkDrMember |  |  |
Accumulated depreciation 12/31/2012 | 1,898 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenFourNineAndFourSevenNineNineEastparkDrMember |  |  |
4851 Homestead Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Houston, TX |  |  |
Encumbrances |  | 3,139 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourEightFiveOneHomesteadRoadMember |  |
Initial Cost of Land | 491 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourEightFiveOneHomesteadRoadMember |  |  |
Building and Improvements | 2,782 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourEightFiveOneHomesteadRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,549 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourEightFiveOneHomesteadRoadMember |  |  |
Land | 504 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourEightFiveOneHomesteadRoadMember |  |  |
Building and improvements | 4,318 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourEightFiveOneHomesteadRoadMember |  |  |
Total | 4,822 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourEightFiveOneHomesteadRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 1,684 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourEightFiveOneHomesteadRoadMember |  |  |
3365-3385 Rauch Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Houston, TX |  |  |
Encumbrances |  | 1,622 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThreeSixFiveAndThreeThreeEightFiveRauchStreetMember |  |
Initial Cost of Land | 284 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThreeSixFiveAndThreeThreeEightFiveRauchStreetMember |  |  |
Building and Improvements | 1,611 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThreeSixFiveAndThreeThreeEightFiveRauchStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 710 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThreeSixFiveAndThreeThreeEightFiveRauchStreetMember |  |  |
Land | 290 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThreeSixFiveAndThreeThreeEightFiveRauchStreetMember |  |  |
Building and improvements | 2,315 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThreeSixFiveAndThreeThreeEightFiveRauchStreetMember |  |  |
Total | 2,605 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThreeSixFiveAndThreeThreeEightFiveRauchStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 1,022 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThreeSixFiveAndThreeThreeEightFiveRauchStreetMember |  |  |
5050 Campbell Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Houston, TX |  |  |
Encumbrances |  | 1,871 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroFiveZeroCampbellRoadMember |  |
Initial Cost of Land | 461 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroFiveZeroCampbellRoadMember |  |  |
Building and Improvements | 2,610 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroFiveZeroCampbellRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,009 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroFiveZeroCampbellRoadMember |  |  |
Land | 470 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroFiveZeroCampbellRoadMember |  |  |
Building and improvements | 3,610 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroFiveZeroCampbellRoadMember |  |  |
Total | 4,080 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroFiveZeroCampbellRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 1,316 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroFiveZeroCampbellRoadMember |  |  |
4300 Pine Timbers [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Houston, TX |  |  |
Encumbrances |  | 2,712 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThreeZeroZeroPineTimbersMember |  |
Initial Cost of Land | 489 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThreeZeroZeroPineTimbersMember |  |  |
Building and Improvements | 2,769 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThreeZeroZeroPineTimbersMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 756 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThreeZeroZeroPineTimbersMember |  |  |
Land | 499 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThreeZeroZeroPineTimbersMember |  |  |
Building and improvements | 3,515 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThreeZeroZeroPineTimbersMember |  |  |
Total | 4,014 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThreeZeroZeroPineTimbersMember |  |  |
Accumulated depreciation 12/31/2012 | 1,476 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThreeZeroZeroPineTimbersMember |  |  |
2500-2530 Fairway Park Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Houston, TX |  |  |
Encumbrances |  | 3,287 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFiveZeroZeroAndTwoFiveThreeZeroFairwayParkDriveMember |  |
Initial Cost of Land | 766 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFiveZeroZeroAndTwoFiveThreeZeroFairwayParkDriveMember |  |  |
Building and Improvements | 4,342 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFiveZeroZeroAndTwoFiveThreeZeroFairwayParkDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 2,059 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFiveZeroZeroAndTwoFiveThreeZeroFairwayParkDriveMember |  |  |
Land | 792 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFiveZeroZeroAndTwoFiveThreeZeroFairwayParkDriveMember |  |  |
Building and improvements | 6,375 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFiveZeroZeroAndTwoFiveThreeZeroFairwayParkDriveMember |  |  |
Total | 7,167 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFiveZeroZeroAndTwoFiveThreeZeroFairwayParkDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 2,419 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFiveZeroZeroAndTwoFiveThreeZeroFairwayParkDriveMember |  |  |
6550 Longpointe [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Houston, TX |  |  |
Encumbrances |  | 1,567 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveFiveZeroLongpointeMember |  |
Initial Cost of Land | 362 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveFiveZeroLongpointeMember |  |  |
Building and Improvements | 2,050 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveFiveZeroLongpointeMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,004 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveFiveZeroLongpointeMember |  |  |
Land | 370 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveFiveZeroLongpointeMember |  |  |
Building and improvements | 3,046 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveFiveZeroLongpointeMember |  |  |
Total | 3,416 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveFiveZeroLongpointeMember |  |  |
Accumulated depreciation 12/31/2012 | 1,092 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveFiveZeroLongpointeMember |  |  |
1815 Turning Basin Dr [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Houston, TX |  |  |
Encumbrances |  | 1,992 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightOneFiveTurningBasinDrMember |  |
Initial Cost of Land | 487 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightOneFiveTurningBasinDrMember |  |  |
Building and Improvements | 2,761 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightOneFiveTurningBasinDrMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,095 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightOneFiveTurningBasinDrMember |  |  |
Land | 531 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightOneFiveTurningBasinDrMember |  |  |
Building and improvements | 3,812 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightOneFiveTurningBasinDrMember |  |  |
Total | 4,343 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightOneFiveTurningBasinDrMember |  |  |
Accumulated depreciation 12/31/2012 | 1,443 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightOneFiveTurningBasinDrMember |  |  |
1819 Turning Basin Dr [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Houston, TX |  |  |
Initial Cost of Land | 231 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightOneNineTurningBasinDrMember |  |  |
Building and Improvements | 1,308 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightOneNineTurningBasinDrMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 591 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightOneNineTurningBasinDrMember |  |  |
Land | 251 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightOneNineTurningBasinDrMember |  |  |
Building and improvements | 1,879 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightOneNineTurningBasinDrMember |  |  |
Total | 2,130 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightOneNineTurningBasinDrMember |  |  |
Accumulated depreciation 12/31/2012 | 753 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightOneNineTurningBasinDrMember |  |  |
1805 Turning Basin Dr [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Houston, TX |  |  |
Encumbrances |  | 2,559 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightZeroFiveTurningBasinDriveMember |  |
Initial Cost of Land | 564 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightZeroFiveTurningBasinDriveMember |  |  |
Building and Improvements | 3,197 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightZeroFiveTurningBasinDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,820 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightZeroFiveTurningBasinDriveMember |  |  |
Land | 616 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightZeroFiveTurningBasinDriveMember |  |  |
Building and improvements | 4,965 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightZeroFiveTurningBasinDriveMember |  |  |
Total | 5,581 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightZeroFiveTurningBasinDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,708 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightZeroFiveTurningBasinDriveMember |  |  |
9835A Genard Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Houston, TX |  |  |
Initial Cost of Land | 1,505 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightThreeFiveGenardRoadMember |  |  |
Building and Improvements | 8,333 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightThreeFiveGenardRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 3,257 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightThreeFiveGenardRoadMember |  |  |
Land | 1,581 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightThreeFiveGenardRoadMember |  |  |
Building and improvements | 11,514 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightThreeFiveGenardRoadMember |  |  |
Total | 13,095 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightThreeFiveGenardRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 3,962 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightThreeFiveGenardRoadMember |  |  |
9835B Genard Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Houston, TX |  |  |
Initial Cost of Land | 245 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightThreeFiveBGenardRoadMember |  |  |
Building and Improvements | 1,357 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightThreeFiveBGenardRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 663 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightThreeFiveBGenardRoadMember |  |  |
Land | 256 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightThreeFiveBGenardRoadMember |  |  |
Building and improvements | 2,009 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightThreeFiveBGenardRoadMember |  |  |
Total | 2,265 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightThreeFiveBGenardRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 690 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineEightThreeFiveBGenardRoadMember |  |  |
11505 State Highway 225 [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | LaPorte City, TX |  |  |
Initial Cost of Land | 940 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFiveZeroFiveStateHighwayTwoTwoFiveMember |  |  |
Building and Improvements | 4,675 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFiveZeroFiveStateHighwayTwoTwoFiveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 606 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFiveZeroFiveStateHighwayTwoTwoFiveMember |  |  |
Land | 940 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFiveZeroFiveStateHighwayTwoTwoFiveMember |  |  |
Building and improvements | 5,281 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFiveZeroFiveStateHighwayTwoTwoFiveMember |  |  |
Total | 6,221 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFiveZeroFiveStateHighwayTwoTwoFiveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,847 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFiveZeroFiveStateHighwayTwoTwoFiveMember |  |  |
1500 E. Main Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Houston, TX |  |  |
Initial Cost of Land | 201 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveZeroZeroEMainStreetMember |  |  |
Building and Improvements | 1,328 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveZeroZeroEMainStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (26)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveZeroZeroEMainStreetMember |  |  |
Land | 204 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveZeroZeroEMainStreetMember |  |  |
Building and improvements | 1,299 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveZeroZeroEMainStreetMember |  |  |
Total | 1,503 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveZeroZeroEMainStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 858 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveZeroZeroEMainStreetMember |  |  |
7230-7238 Wynnwood [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Houston, TX |  |  |
Initial Cost of Land | 254 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenTwoThreeZeroToSevenTwoThreeEightWynnwoodMember |  |  |
Building and Improvements | 764 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenTwoThreeZeroToSevenTwoThreeEightWynnwoodMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 173 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenTwoThreeZeroToSevenTwoThreeEightWynnwoodMember |  |  |
Land | 259 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenTwoThreeZeroToSevenTwoThreeEightWynnwoodMember |  |  |
Building and improvements | 932 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenTwoThreeZeroToSevenTwoThreeEightWynnwoodMember |  |  |
Total | 1,191 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenTwoThreeZeroToSevenTwoThreeEightWynnwoodMember |  |  |
Accumulated depreciation 12/31/2012 | 349 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenTwoThreeZeroToSevenTwoThreeEightWynnwoodMember |  |  |
7240-7248 Wynnwood [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Houston, TX |  |  |
Initial Cost of Land | 271 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenTwoFourZeroToSevenTwoFourEightWynnwoodMember |  |  |
Building and Improvements | 726 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenTwoFourZeroToSevenTwoFourEightWynnwoodMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 35 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenTwoFourZeroToSevenTwoFourEightWynnwoodMember |  |  |
Land | 276 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenTwoFourZeroToSevenTwoFourEightWynnwoodMember |  |  |
Building and improvements | 756 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenTwoFourZeroToSevenTwoFourEightWynnwoodMember |  |  |
Total | 1,032 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenTwoFourZeroToSevenTwoFourEightWynnwoodMember |  |  |
Accumulated depreciation 12/31/2012 | 342 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenTwoFourZeroToSevenTwoFourEightWynnwoodMember |  |  |
7250-7260 Wynnwood [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Houston, TX |  |  |
Initial Cost of Land | 200 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenTwoFiveZeroToSevenTwoSixZeroWynnwoodMember |  |  |
Building and Improvements | 481 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenTwoFiveZeroToSevenTwoSixZeroWynnwoodMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 141 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenTwoFiveZeroToSevenTwoSixZeroWynnwoodMember |  |  |
Land | 203 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenTwoFiveZeroToSevenTwoSixZeroWynnwoodMember |  |  |
Building and improvements | 619 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenTwoFiveZeroToSevenTwoSixZeroWynnwoodMember |  |  |
Total | 822 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenTwoFiveZeroToSevenTwoSixZeroWynnwoodMember |  |  |
Accumulated depreciation 12/31/2012 | 227 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenTwoFiveZeroToSevenTwoSixZeroWynnwoodMember |  |  |
6400 Long Point [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Houston, TX |  |  |
Initial Cost of Land | 188 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFourZeroZeroLongPointMember |  |  |
Building and Improvements | 898 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFourZeroZeroLongPointMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (47)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFourZeroZeroLongPointMember |  |  |
Land | 188 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFourZeroZeroLongPointMember |  |  |
Building and improvements | 851 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFourZeroZeroLongPointMember |  |  |
Total | 1,039 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFourZeroZeroLongPointMember |  |  |
Accumulated depreciation 12/31/2012 | 291 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFourZeroZeroLongPointMember |  |  |
12705 S. Kirkwood, Ste 100-150 [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Stafford, TX |  |  |
Initial Cost of Land | 154 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenZeroFiveSKirkwoodSteOneZeroZeroToOneFiveZeroMember |  |  |
Building and Improvements | 626 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenZeroFiveSKirkwoodSteOneZeroZeroToOneFiveZeroMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 8 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenZeroFiveSKirkwoodSteOneZeroZeroToOneFiveZeroMember |  |  |
Land | 155 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenZeroFiveSKirkwoodSteOneZeroZeroToOneFiveZeroMember |  |  |
Building and improvements | 633 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenZeroFiveSKirkwoodSteOneZeroZeroToOneFiveZeroMember |  |  |
Total | 788 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenZeroFiveSKirkwoodSteOneZeroZeroToOneFiveZeroMember |  |  |
Accumulated depreciation 12/31/2012 | 166 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenZeroFiveSKirkwoodSteOneZeroZeroToOneFiveZeroMember |  |  |
12705 S. Kirkwood, Ste 200-220 [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Stafford, TX |  |  |
Initial Cost of Land | 404 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenZeroFiveSKirkwoodSteTwoZeroZeroToTwoTwoZeroMember |  |  |
Building and Improvements | 1,698 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenZeroFiveSKirkwoodSteTwoZeroZeroToTwoTwoZeroMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 275 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenZeroFiveSKirkwoodSteTwoZeroZeroToTwoTwoZeroMember |  |  |
Land | 393 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenZeroFiveSKirkwoodSteTwoZeroZeroToTwoTwoZeroMember |  |  |
Building and improvements | 1,984 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenZeroFiveSKirkwoodSteTwoZeroZeroToTwoTwoZeroMember |  |  |
Total | 2,377 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenZeroFiveSKirkwoodSteTwoZeroZeroToTwoTwoZeroMember |  |  |
Accumulated depreciation 12/31/2012 | 747 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenZeroFiveSKirkwoodSteTwoZeroZeroToTwoTwoZeroMember |  |  |
8850 Jameel [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Houston, TX |  |  |
Initial Cost of Land | 171 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightEightFiveZeroJameelMember |  |  |
Building and Improvements | 826 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightEightFiveZeroJameelMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 4 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightEightFiveZeroJameelMember |  |  |
Land | 171 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightEightFiveZeroJameelMember |  |  |
Building and improvements | 830 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightEightFiveZeroJameelMember |  |  |
Total | 1,001 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightEightFiveZeroJameelMember |  |  |
Accumulated depreciation 12/31/2012 | 305 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightEightFiveZeroJameelMember |  |  |
8800 Jameel [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Houston, TX |  |  |
Initial Cost of Land | 163 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightEightZeroZeroJameelMember |  |  |
Building and Improvements | 798 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightEightZeroZeroJameelMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (100)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightEightZeroZeroJameelMember |  |  |
Land | 124 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightEightZeroZeroJameelMember |  |  |
Building and improvements | 737 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightEightZeroZeroJameelMember |  |  |
Total | 861 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightEightZeroZeroJameelMember |  |  |
Accumulated depreciation 12/31/2012 | 264 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightEightZeroZeroJameelMember |  |  |
8700 Jameel [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Houston, TX |  |  |
Initial Cost of Land | 170 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightSevenZeroZeroJameelMember |  |  |
Building and Improvements | 1,020 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightSevenZeroZeroJameelMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (178)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightSevenZeroZeroJameelMember |  |  |
Land | 120 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightSevenZeroZeroJameelMember |  |  |
Building and improvements | 892 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightSevenZeroZeroJameelMember |  |  |
Total | 1,012 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightSevenZeroZeroJameelMember |  |  |
Accumulated depreciation 12/31/2012 | 236 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightSevenZeroZeroJameelMember |  |  |
8600 Jameel [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Houston, TX |  |  |
Initial Cost of Land | 163 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightSixZeroZeroJameelMember |  |  |
Building and Improvements | 818 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightSixZeroZeroJameelMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 41 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightSixZeroZeroJameelMember |  |  |
Land | 163 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightSixZeroZeroJameelMember |  |  |
Building and improvements | 859 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightSixZeroZeroJameelMember |  |  |
Total | 1,022 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightSixZeroZeroJameelMember |  |  |
Accumulated depreciation 12/31/2012 | 313 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightSixZeroZeroJameelMember |  |  |
7967 Blankenship [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Houston, TX |  |  |
Initial Cost of Land | 307 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenNineSixSevenBlankenshipMember |  |  |
Building and Improvements | 1,166 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenNineSixSevenBlankenshipMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 337 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenNineSixSevenBlankenshipMember |  |  |
Land | 307 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenNineSixSevenBlankenshipMember |  |  |
Building and improvements | 1,503 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenNineSixSevenBlankenshipMember |  |  |
Total | 1,810 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenNineSixSevenBlankenshipMember |  |  |
Accumulated depreciation 12/31/2012 | 363 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenNineSixSevenBlankenshipMember |  |  |
8800 City Park Look East [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Houston, TX |  |  |
Encumbrances | 23,226 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightEightZeroZeroCityParkLookEastMember |  |  |
Initial Cost of Land | 3,717 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightEightZeroZeroCityParkLookEastMember |  |  |
Building and Improvements | 19,237 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightEightZeroZeroCityParkLookEastMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (659)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightEightZeroZeroCityParkLookEastMember |  |  |
Land | 3,717 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightEightZeroZeroCityParkLookEastMember |  |  |
Building and improvements | 18,578 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightEightZeroZeroCityParkLookEastMember |  |  |
Total | 22,295 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightEightZeroZeroCityParkLookEastMember |  |  |
Accumulated depreciation 12/31/2012 | 2,726 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightEightZeroZeroCityParkLookEastMember |  |  |
Four Thousand Eight Hundred West Greens Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Houston, TX |  |  |
Initial Cost of Land | 3,350 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandEightHundredWestGreensRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 12,057 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandEightHundredWestGreensRoadMember |  |  |
Land | 3,318 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandEightHundredWestGreensRoadMember |  |  |
Building and improvements | 12,089 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandEightHundredWestGreensRoadMember |  |  |
Total | 15,407 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandEightHundredWestGreensRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 75 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandEightHundredWestGreensRoadMember |  |  |
2900 N Shadeland Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Indianapolis, IN |  |  |
Initial Cost of Land | 2,057 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineZeroZeroNShadelandAvenueMember |  |  |
Building and Improvements | 13,565 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineZeroZeroNShadelandAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 3,828 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineZeroZeroNShadelandAvenueMember |  |  |
Land | 2,057 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineZeroZeroNShadelandAvenueMember |  |  |
Building and improvements | 17,393 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineZeroZeroNShadelandAvenueMember |  |  |
Total | 19,450 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineZeroZeroNShadelandAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 7,484 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoNineZeroZeroNShadelandAvenueMember |  |  |
1445 Brookville Way [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Indianapolis, IN |  |  |
Initial Cost of Land | 459 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourFourFiveBrookvilleWayMember |  |  |
Building and Improvements | 2,603 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourFourFiveBrookvilleWayMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,063 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourFourFiveBrookvilleWayMember |  |  |
Land | 476 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourFourFiveBrookvilleWayMember |  |  |
Building and improvements | 3,649 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourFourFiveBrookvilleWayMember |  |  |
Total | 4,125 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourFourFiveBrookvilleWayMember |  |  |
Accumulated depreciation 12/31/2012 | 1,548 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourFourFiveBrookvilleWayMember |  |  |
1440 Brookville Way [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Indianapolis, IN |  |  |
Encumbrances | 3,661 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourFourZeroBrookvilleWayMember |  |  |
Initial Cost of Land | 665 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourFourZeroBrookvilleWayMember |  |  |
Building and Improvements | 3,770 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourFourZeroBrookvilleWayMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 985 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourFourZeroBrookvilleWayMember |  |  |
Land | 685 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourFourZeroBrookvilleWayMember |  |  |
Building and improvements | 4,735 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourFourZeroBrookvilleWayMember |  |  |
Total | 5,420 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourFourZeroBrookvilleWayMember |  |  |
Accumulated depreciation 12/31/2012 | 2,049 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourFourZeroBrookvilleWayMember |  |  |
1240 Brookville Way [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Indianapolis, IN |  |  |
Initial Cost of Land | 247 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoFourZeroBrookvilleWayMember |  |  |
Building and Improvements | 1,402 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoFourZeroBrookvilleWayMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 324 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoFourZeroBrookvilleWayMember |  |  |
Land | 258 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoFourZeroBrookvilleWayMember |  |  |
Building and improvements | 1,715 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoFourZeroBrookvilleWayMember |  |  |
Total | 1,973 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoFourZeroBrookvilleWayMember |  |  |
Accumulated depreciation 12/31/2012 | 776 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoFourZeroBrookvilleWayMember |  |  |
1345 Brookville Way [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Indianapolis, IN |  |  |
Initial Cost of Land | 586 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFourFiveBrookvilleWayMember |  |  |
Building and Improvements | 3,321 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFourFiveBrookvilleWayMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,160 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFourFiveBrookvilleWayMember |  |  |
Land | 601 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFourFiveBrookvilleWayMember |  |  |
Building and improvements | 4,466 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFourFiveBrookvilleWayMember |  |  |
Total | 5,067 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFourFiveBrookvilleWayMember |  |  |
Accumulated depreciation 12/31/2012 | 1,872 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFourFiveBrookvilleWayMember |  |  |
1350 Brookville Way [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Indianapolis, IN |  |  |
Initial Cost of Land | 205 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFiveZeroBrookvilleWayMember |  |  |
Building and Improvements | 1,161 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFiveZeroBrookvilleWayMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 249 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFiveZeroBrookvilleWayMember |  |  |
Land | 204 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFiveZeroBrookvilleWayMember |  |  |
Building and improvements | 1,411 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFiveZeroBrookvilleWayMember |  |  |
Total | 1,615 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFiveZeroBrookvilleWayMember |  |  |
Accumulated depreciation 12/31/2012 | 639 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFiveZeroBrookvilleWayMember |  |  |
1341 Sadlier Circle South [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Indianapolis, IN |  |  |
Initial Cost of Land | 131 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFourOneSadlierCircleSouthMember |  |  |
Building and Improvements | 743 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFourOneSadlierCircleSouthMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 205 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFourOneSadlierCircleSouthMember |  |  |
Land | 136 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFourOneSadlierCircleSouthMember |  |  |
Building and improvements | 943 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFourOneSadlierCircleSouthMember |  |  |
Total | 1,079 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFourOneSadlierCircleSouthMember |  |  |
Accumulated depreciation 12/31/2012 | 414 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFourOneSadlierCircleSouthMember |  |  |
1322-1438 Sadlier Circle East [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Indianapolis, IN |  |  |
Initial Cost of Land | 145 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeTwoTwoToOneFourThreeEightSadlierCircleEDrMember |  |  |
Building and Improvements | 822 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeTwoTwoToOneFourThreeEightSadlierCircleEDrMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 296 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeTwoTwoToOneFourThreeEightSadlierCircleEDrMember |  |  |
Land | 152 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeTwoTwoToOneFourThreeEightSadlierCircleEDrMember |  |  |
Building and improvements | 1,111 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeTwoTwoToOneFourThreeEightSadlierCircleEDrMember |  |  |
Total | 1,263 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeTwoTwoToOneFourThreeEightSadlierCircleEDrMember |  |  |
Accumulated depreciation 12/31/2012 | 491 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeTwoTwoToOneFourThreeEightSadlierCircleEDrMember |  |  |
1327-1441 Sadlier Circle West [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Indianapolis, IN |  |  |
Initial Cost of Land | 218 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeTwoSevenToOneFourFourOneSadlierCircleEDrMember |  |  |
Building and Improvements | 1,234 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeTwoSevenToOneFourFourOneSadlierCircleEDrMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 607 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeTwoSevenToOneFourFourOneSadlierCircleEDrMember |  |  |
Land | 225 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeTwoSevenToOneFourFourOneSadlierCircleEDrMember |  |  |
Building and improvements | 1,834 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeTwoSevenToOneFourFourOneSadlierCircleEDrMember |  |  |
Total | 2,059 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeTwoSevenToOneFourFourOneSadlierCircleEDrMember |  |  |
Accumulated depreciation 12/31/2012 | 740 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeTwoSevenToOneFourFourOneSadlierCircleEDrMember |  |  |
1402-1430 Sadlier Circle West [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Indianapolis, IN |  |  |
Initial Cost of Land | 165 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourZeroTwoToOneFourThreeZeroSadlierCircleWestMember |  |  |
Building and Improvements | 934 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourZeroTwoToOneFourThreeZeroSadlierCircleWestMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 398 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourZeroTwoToOneFourThreeZeroSadlierCircleWestMember |  |  |
Land | 171 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourZeroTwoToOneFourThreeZeroSadlierCircleWestMember |  |  |
Building and improvements | 1,326 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourZeroTwoToOneFourThreeZeroSadlierCircleWestMember |  |  |
Total | 1,497 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourZeroTwoToOneFourThreeZeroSadlierCircleWestMember |  |  |
Accumulated depreciation 12/31/2012 | 581 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourZeroTwoToOneFourThreeZeroSadlierCircleWestMember |  |  |
1504 Sadlier Circle South [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Indianapolis, IN |  |  |
Initial Cost of Land | 219 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveZeroFourSadlierCircleEDrMember |  |  |
Building and Improvements | 1,238 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveZeroFourSadlierCircleEDrMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (104)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveZeroFourSadlierCircleEDrMember |  |  |
Land | 115 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveZeroFourSadlierCircleEDrMember |  |  |
Building and improvements | 1,238 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveZeroFourSadlierCircleEDrMember |  |  |
Total | 1,353 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveZeroFourSadlierCircleEDrMember |  |  |
Accumulated depreciation 12/31/2012 | 746 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveZeroFourSadlierCircleEDrMember |  |  |
1365-1367 Sadlier Way Circle East [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Indianapolis, IN |  |  |
Initial Cost of Land | 121 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeSixFiveToOneThreeSixSevenSadlierCircleEastMember |  |  |
Building and Improvements | 688 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeSixFiveToOneThreeSixSevenSadlierCircleEastMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 181 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeSixFiveToOneThreeSixSevenSadlierCircleEastMember |  |  |
Land | 91 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeSixFiveToOneThreeSixSevenSadlierCircleEastMember |  |  |
Building and improvements | 899 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeSixFiveToOneThreeSixSevenSadlierCircleEastMember |  |  |
Total | 990 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeSixFiveToOneThreeSixSevenSadlierCircleEastMember |  |  |
Accumulated depreciation 12/31/2012 | 393 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeSixFiveToOneThreeSixSevenSadlierCircleEastMember |  |  |
1352-1354 Sadlier Circle West [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Indianapolis, IN |  |  |
Initial Cost of Land | 178 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFiveTwoToOneThreeFiveFourSadlierCircleEDrMember |  |  |
Building and Improvements | 1,008 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFiveTwoToOneThreeFiveFourSadlierCircleEDrMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 186 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFiveTwoToOneThreeFiveFourSadlierCircleEDrMember |  |  |
Land | 166 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFiveTwoToOneThreeFiveFourSadlierCircleEDrMember |  |  |
Building and improvements | 1,206 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFiveTwoToOneThreeFiveFourSadlierCircleEDrMember |  |  |
Total | 1,372 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFiveTwoToOneThreeFiveFourSadlierCircleEDrMember |  |  |
Accumulated depreciation 12/31/2012 | 541 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeFiveTwoToOneThreeFiveFourSadlierCircleEDrMember |  |  |
1335 Sadlier Circle East [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Indianapolis, IN |  |  |
Initial Cost of Land | 81 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeThreeFiveSadlierCircleEDrMember |  |  |
Building and Improvements | 460 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeThreeFiveSadlierCircleEDrMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 202 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeThreeFiveSadlierCircleEDrMember |  |  |
Land | 85 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeThreeFiveSadlierCircleEDrMember |  |  |
Building and improvements | 658 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeThreeFiveSadlierCircleEDrMember |  |  |
Total | 743 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeThreeFiveSadlierCircleEDrMember |  |  |
Accumulated depreciation 12/31/2012 | 287 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeThreeFiveSadlierCircleEDrMember |  |  |
1425 Sadlier Circle West [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Indianapolis, IN |  |  |
Initial Cost of Land | 21 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourTwoFiveSadlierCircleEDrMember |  |  |
Building and Improvements | 117 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourTwoFiveSadlierCircleEDrMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 41 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourTwoFiveSadlierCircleEDrMember |  |  |
Land | 23 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourTwoFiveSadlierCircleEDrMember |  |  |
Building and improvements | 156 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourTwoFiveSadlierCircleEDrMember |  |  |
Total | 179 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourTwoFiveSadlierCircleEDrMember |  |  |
Accumulated depreciation 12/31/2012 | 67 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourTwoFiveSadlierCircleEDrMember |  |  |
6951 East 30th St [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Indianapolis, IN |  |  |
Initial Cost of Land | 256 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixNineFiveOneEThreeZeroStreetMember |  |  |
Building and Improvements | 1,449 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixNineFiveOneEThreeZeroStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 227 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixNineFiveOneEThreeZeroStreetMember |  |  |
Land | 265 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixNineFiveOneEThreeZeroStreetMember |  |  |
Building and improvements | 1,667 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixNineFiveOneEThreeZeroStreetMember |  |  |
Total | 1,932 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixNineFiveOneEThreeZeroStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 754 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixNineFiveOneEThreeZeroStreetMember |  |  |
6701 East 30th St [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Indianapolis, IN |  |  |
Initial Cost of Land | 78 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSevenZeroOneEThreeZeroStreetMember |  |  |
Building and Improvements | 443 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSevenZeroOneEThreeZeroStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 98 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSevenZeroOneEThreeZeroStreetMember |  |  |
Land | 82 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSevenZeroOneEThreeZeroStreetMember |  |  |
Building and improvements | 537 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSevenZeroOneEThreeZeroStreetMember |  |  |
Total | 619 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSevenZeroOneEThreeZeroStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 247 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSevenZeroOneEThreeZeroStreetMember |  |  |
6737 East 30th St [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Indianapolis, IN |  |  |
Encumbrances | 1,722 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSevenThreeSevenEThreeZeroStreetMember |  |  |
Initial Cost of Land | 385 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSevenThreeSevenEThreeZeroStreetMember |  |  |
Building and Improvements | 2,181 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSevenThreeSevenEThreeZeroStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 222 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSevenThreeSevenEThreeZeroStreetMember |  |  |
Land | 398 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSevenThreeSevenEThreeZeroStreetMember |  |  |
Building and improvements | 2,390 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSevenThreeSevenEThreeZeroStreetMember |  |  |
Total | 2,788 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSevenThreeSevenEThreeZeroStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 1,098 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSevenThreeSevenEThreeZeroStreetMember |  |  |
6555 East 30th St [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Indianapolis, IN |  |  |
Initial Cost of Land | 484 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveFiveFiveEThreeZeroStreetMember |  |  |
Building and Improvements | 4,760 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveFiveFiveEThreeZeroStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 2,065 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveFiveFiveEThreeZeroStreetMember |  |  |
Land | 484 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveFiveFiveEThreeZeroStreetMember |  |  |
Building and improvements | 6,825 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveFiveFiveEThreeZeroStreetMember |  |  |
Total | 7,309 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveFiveFiveEThreeZeroStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 2,870 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveFiveFiveEThreeZeroStreetMember |  |  |
7901 West 21st St. [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Indianapolis, IN |  |  |
Encumbrances | 4,946 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenNineZeroOneWestTwentyOneStMember |  |  |
Initial Cost of Land | 1,048 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenNineZeroOneWestTwentyOneStMember |  |  |
Building and Improvements | 6,027 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenNineZeroOneWestTwentyOneStMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 246 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenNineZeroOneWestTwentyOneStMember |  |  |
Land | 1,048 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenNineZeroOneWestTwentyOneStMember |  |  |
Building and improvements | 6,273 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenNineZeroOneWestTwentyOneStMember |  |  |
Total | 7,321 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenNineZeroOneWestTwentyOneStMember |  |  |
Accumulated depreciation 12/31/2012 | 2,725 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenNineZeroOneWestTwentyOneStMember |  |  |
1225 Brookville Way [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Indianapolis, IN |  |  |
Initial Cost of Land | 60 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoTwoFiveBrookvilleWayMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 417 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoTwoFiveBrookvilleWayMember |  |  |
Land | 68 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoTwoFiveBrookvilleWayMember |  |  |
Building and improvements | 409 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoTwoFiveBrookvilleWayMember |  |  |
Total | 477 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoTwoFiveBrookvilleWayMember |  |  |
Accumulated depreciation 12/31/2012 | 172 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoTwoFiveBrookvilleWayMember |  |  |
6751 E 30th St [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Indianapolis, IN |  |  |
Encumbrances | 2,420 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSevenFiveOneEThirtyStMember |  |  |
Initial Cost of Land | 728 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSevenFiveOneEThirtyStMember |  |  |
Building and Improvements | 2,837 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSevenFiveOneEThirtyStMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 354 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSevenFiveOneEThirtyStMember |  |  |
Land | 741 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSevenFiveOneEThirtyStMember |  |  |
Building and improvements | 3,178 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSevenFiveOneEThirtyStMember |  |  |
Total | 3,919 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSevenFiveOneEThirtyStMember |  |  |
Accumulated depreciation 12/31/2012 | 1,301 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSevenFiveOneEThirtyStMember |  |  |
6575 East 30th Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Indianapolis, IN |  |  |
Encumbrances | 1,814 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveSevenFiveEastThreeZeroStreetMember |  |  |
Initial Cost of Land | 118 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveSevenFiveEastThreeZeroStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 2,068 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveSevenFiveEastThreeZeroStreetMember |  |  |
Land | 128 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveSevenFiveEastThreeZeroStreetMember |  |  |
Building and improvements | 2,058 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveSevenFiveEastThreeZeroStreetMember |  |  |
Total | 2,186 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveSevenFiveEastThreeZeroStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 880 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveSevenFiveEastThreeZeroStreetMember |  |  |
6585 East 30th Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Indianapolis, IN |  |  |
Encumbrances | 2,814 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveEightFiveEastThreeZeroStreetMember |  |  |
Initial Cost of Land | 196 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveEightFiveEastThreeZeroStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 3,195 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveEightFiveEastThreeZeroStreetMember |  |  |
Land | 196 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveEightFiveEastThreeZeroStreetMember |  |  |
Building and improvements | 3,195 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveEightFiveEastThreeZeroStreetMember |  |  |
Total | 3,391 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveEightFiveEastThreeZeroStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 1,278 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFiveEightFiveEastThreeZeroStreetMember |  |  |
5705-97 Park Plaza Ct. [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Indianapolis, IN |  |  |
Encumbrances | 2,464 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveSevenZeroFiveToNineSevenParkPlazaCourtMember |  |  |
Initial Cost of Land | 600 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveSevenZeroFiveToNineSevenParkPlazaCourtMember |  |  |
Building and Improvements | 2,194 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveSevenZeroFiveToNineSevenParkPlazaCourtMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 853 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveSevenZeroFiveToNineSevenParkPlazaCourtMember |  |  |
Land | 609 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveSevenZeroFiveToNineSevenParkPlazaCourtMember |  |  |
Building and improvements | 3,038 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveSevenZeroFiveToNineSevenParkPlazaCourtMember |  |  |
Total | 3,647 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveSevenZeroFiveToNineSevenParkPlazaCourtMember |  |  |
Accumulated depreciation 12/31/2012 | 1,070 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveSevenZeroFiveToNineSevenParkPlazaCourtMember |  |  |
9319-9341 Castlegate Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Indianapolis, IN |  |  |
Initial Cost of Land | 530 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThreeOneNineToNineThreeFourOneCastlegateDriveMember |  |  |
Building and Improvements | 1,235 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThreeOneNineToNineThreeFourOneCastlegateDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 688 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThreeOneNineToNineThreeFourOneCastlegateDriveMember |  |  |
Land | 544 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThreeOneNineToNineThreeFourOneCastlegateDriveMember |  |  |
Building and improvements | 1,909 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThreeOneNineToNineThreeFourOneCastlegateDriveMember |  |  |
Total | 2,453 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThreeOneNineToNineThreeFourOneCastlegateDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 652 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineThreeOneNineToNineThreeFourOneCastlegateDriveMember |  |  |
1133 Northwest L Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Richmond, IN |  |  |
Initial Cost of Land | 201 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneThreeThreeNorthwestLStreetMember |  |  |
Building and Improvements | 1,358 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneThreeThreeNorthwestLStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (188)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneThreeThreeNorthwestLStreetMember |  |  |
Land | 208 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneThreeThreeNorthwestLStreetMember |  |  |
Building and improvements | 1,163 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneThreeThreeNorthwestLStreetMember |  |  |
Total | 1,371 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneThreeThreeNorthwestLStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 636 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneThreeThreeNorthwestLStreetMember |  |  |
14425 Bergen Blvd [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Noblesville, IN |  |  |
Initial Cost of Land | 647 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourFourTwoFiveBergenBlvdMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 3,484 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourFourTwoFiveBergenBlvdMember |  |  |
Land | 743 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourFourTwoFiveBergenBlvdMember |  |  |
Building and improvements | 3,388 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourFourTwoFiveBergenBlvdMember |  |  |
Total | 4,131 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourFourTwoFiveBergenBlvdMember |  |  |
Accumulated depreciation 12/31/2012 | 615 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourFourTwoFiveBergenBlvdMember |  |  |
4700 NW 15th Ave [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Ft. Lauderdale, FL |  |  |
Initial Cost of Land | 908 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenZeroZeroNwOneFiveAvenueMember |  |  |
Building and Improvements | 1,883 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenZeroZeroNwOneFiveAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 269 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenZeroZeroNwOneFiveAvenueMember |  |  |
Land | 912 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenZeroZeroNwOneFiveAvenueMember |  |  |
Building and improvements | 2,148 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenZeroZeroNwOneFiveAvenueMember |  |  |
Total | 3,060 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenZeroZeroNwOneFiveAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 777 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenZeroZeroNwOneFiveAvenueMember |  |  |
4710 NW 15th Ave [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Ft. Lauderdale, FL |  |  |
Initial Cost of Land | 830 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenOneZeroNwOneFiveAvenueMember |  |  |
Building and Improvements | 2,722 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenOneZeroNwOneFiveAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 346 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenOneZeroNwOneFiveAvenueMember |  |  |
Land | 834 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenOneZeroNwOneFiveAvenueMember |  |  |
Building and improvements | 3,064 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenOneZeroNwOneFiveAvenueMember |  |  |
Total | 3,898 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenOneZeroNwOneFiveAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 856 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenOneZeroNwOneFiveAvenueMember |  |  |
4720 NW 15th Ave [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Ft. Lauderdale, FL |  |  |
Initial Cost of Land | 937 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenTwoZeroNwOneFiveAvenueMember |  |  |
Building and Improvements | 2,455 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenTwoZeroNwOneFiveAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 404 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenTwoZeroNwOneFiveAvenueMember |  |  |
Land | 942 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenTwoZeroNwOneFiveAvenueMember |  |  |
Building and improvements | 2,854 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenTwoZeroNwOneFiveAvenueMember |  |  |
Total | 3,796 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenTwoZeroNwOneFiveAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 828 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenTwoZeroNwOneFiveAvenueMember |  |  |
4740 NW 15th Ave [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Ft. Lauderdale, FL |  |  |
Initial Cost of Land | 1,107 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenFourZeroNwOneFiveAvenueMember |  |  |
Building and Improvements | 3,111 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenFourZeroNwOneFiveAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 320 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenFourZeroNwOneFiveAvenueMember |  |  |
Land | 1,112 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenFourZeroNwOneFiveAvenueMember |  |  |
Building and improvements | 3,426 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenFourZeroNwOneFiveAvenueMember |  |  |
Total | 4,538 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenFourZeroNwOneFiveAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 944 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenFourZeroNwOneFiveAvenueMember |  |  |
4750 NW 15th Ave [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Ft. Lauderdale, FL |  |  |
Initial Cost of Land | 947 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenFiveZeroNwOneFiveAvenueMember |  |  |
Building and Improvements | 3,079 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenFiveZeroNwOneFiveAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 406 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenFiveZeroNwOneFiveAvenueMember |  |  |
Land | 951 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenFiveZeroNwOneFiveAvenueMember |  |  |
Building and improvements | 3,481 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenFiveZeroNwOneFiveAvenueMember |  |  |
Total | 4,432 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenFiveZeroNwOneFiveAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 785 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenFiveZeroNwOneFiveAvenueMember |  |  |
4800 NW 15th Ave [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Ft. Lauderdale, FL |  |  |
Initial Cost of Land | 1,092 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourEightZeroZeroNwOneFiveAvenueMember |  |  |
Building and Improvements | 3,308 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourEightZeroZeroNwOneFiveAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 514 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourEightZeroZeroNwOneFiveAvenueMember |  |  |
Land | 1,097 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourEightZeroZeroNwOneFiveAvenueMember |  |  |
Building and improvements | 3,817 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourEightZeroZeroNwOneFiveAvenueMember |  |  |
Total | 4,914 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourEightZeroZeroNwOneFiveAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 1,050 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourEightZeroZeroNwOneFiveAvenueMember |  |  |
Medley Industrial Center [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Medley, FL |  |  |
Initial Cost of Land | 857 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_MedleyIndustrialCenterMember |  |  |
Building and Improvements | 3,428 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_MedleyIndustrialCenterMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 3,988 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_MedleyIndustrialCenterMember |  |  |
Land | 864 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_MedleyIndustrialCenterMember |  |  |
Building and improvements | 7,409 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_MedleyIndustrialCenterMember |  |  |
Total | 8,273 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_MedleyIndustrialCenterMember |  |  |
Accumulated depreciation 12/31/2012 | 1,687 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_MedleyIndustrialCenterMember |  |  |
12601 &12605 NW 115th Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Medley, FL |  |  |
Initial Cost of Land | 2,316 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSixZeroOneAndOneTwoSixZeroFiveNwOneOneSixAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 440 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSixZeroOneAndOneTwoSixZeroFiveNwOneOneSixAvenueMember |  |  |
Land | 762 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSixZeroOneAndOneTwoSixZeroFiveNwOneOneSixAvenueMember |  |  |
Building and improvements | 1,994 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSixZeroOneAndOneTwoSixZeroFiveNwOneOneSixAvenueMember |  |  |
Total | 2,756 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSixZeroOneAndOneTwoSixZeroFiveNwOneOneSixAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 270 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSixZeroOneAndOneTwoSixZeroFiveNwOneOneSixAvenueMember |  |  |
N25 W23255 Paul Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Pewaukee, WI |  |  |
Initial Cost of Land | 569 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NTwoFiveWTwoThreeTwoFiveFivePaulRoadMember |  |  |
Building and Improvements | 3,270 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NTwoFiveWTwoThreeTwoFiveFivePaulRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,836 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NTwoFiveWTwoThreeTwoFiveFivePaulRoadMember |  |  |
Land | 450 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NTwoFiveWTwoThreeTwoFiveFivePaulRoadMember |  |  |
Building and improvements | 5,225 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NTwoFiveWTwoThreeTwoFiveFivePaulRoadMember |  |  |
Total | 5,675 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NTwoFiveWTwoThreeTwoFiveFivePaulRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 1,880 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NTwoFiveWTwoThreeTwoFiveFivePaulRoadMember |  |  |
5355 South Westridge Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | New Berlin, WI |  |  |
Encumbrances | 5,089 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThreeFiveFiveSouthWestridgeDriveMember |  |  |
Initial Cost of Land | 1,630 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThreeFiveFiveSouthWestridgeDriveMember |  |  |
Building and Improvements | 7,058 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThreeFiveFiveSouthWestridgeDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (108)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThreeFiveFiveSouthWestridgeDriveMember |  |  |
Land | 1,646 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThreeFiveFiveSouthWestridgeDriveMember |  |  |
Building and improvements | 6,934 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThreeFiveFiveSouthWestridgeDriveMember |  |  |
Total | 8,580 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThreeFiveFiveSouthWestridgeDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,643 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThreeFiveFiveSouthWestridgeDriveMember |  |  |
320-334 W. Vogel Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Milwaukee, WI |  |  |
Encumbrances | 2,692 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoZeroToThreeThreeFourWVogelAvenueMember |  |  |
Initial Cost of Land | 506 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoZeroToThreeThreeFourWVogelAvenueMember |  |  |
Building and Improvements | 3,199 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoZeroToThreeThreeFourWVogelAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (100)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoZeroToThreeThreeFourWVogelAvenueMember |  |  |
Land | 508 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoZeroToThreeThreeFourWVogelAvenueMember |  |  |
Building and improvements | 3,097 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoZeroToThreeThreeFourWVogelAvenueMember |  |  |
Total | 3,605 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoZeroToThreeThreeFourWVogelAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 1,481 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoZeroToThreeThreeFourWVogelAvenueMember |  |  |
4950 South 6th Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Milwaukee, WI |  |  |
Encumbrances | 1,444 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourNineFiveZeroSouthSixAvenueMember |  |  |
Initial Cost of Land | 299 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourNineFiveZeroSouthSixAvenueMember |  |  |
Building and Improvements | 1,565 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourNineFiveZeroSouthSixAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 273 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourNineFiveZeroSouthSixAvenueMember |  |  |
Land | 301 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourNineFiveZeroSouthSixAvenueMember |  |  |
Building and improvements | 1,836 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourNineFiveZeroSouthSixAvenueMember |  |  |
Total | 2,137 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourNineFiveZeroSouthSixAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 1,026 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourNineFiveZeroSouthSixAvenueMember |  |  |
17005 W. Ryerson Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | New Berlin, WI |  |  |
Encumbrances | 2,915 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenZeroZeroFiveWRyersonRoadMember |  |  |
Initial Cost of Land | 403 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenZeroZeroFiveWRyersonRoadMember |  |  |
Building and Improvements | 3,647 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenZeroZeroFiveWRyersonRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 251 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenZeroZeroFiveWRyersonRoadMember |  |  |
Land | 405 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenZeroZeroFiveWRyersonRoadMember |  |  |
Building and improvements | 3,896 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenZeroZeroFiveWRyersonRoadMember |  |  |
Total | 4,301 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenZeroZeroFiveWRyersonRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 1,549 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenZeroZeroFiveWRyersonRoadMember |  |  |
W140 N9059 Lilly Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Menomonee Falls, WI |  |  |
Initial Cost of Land | 343 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_WOneFourZeroNNineZeroFiveNineLillyRoadMember |  |  |
Building and Improvements | 1,153 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_WOneFourZeroNNineZeroFiveNineLillyRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 117 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_WOneFourZeroNNineZeroFiveNineLillyRoadMember |  |  |
Land | 366 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_WOneFourZeroNNineZeroFiveNineLillyRoadMember |  |  |
Building and improvements | 1,247 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_WOneFourZeroNNineZeroFiveNineLillyRoadMember |  |  |
Total | 1,613 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_WOneFourZeroNNineZeroFiveNineLillyRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 420 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_WOneFourZeroNNineZeroFiveNineLillyRoadMember |  |  |
200 W. Vogel Avenue-Bldg B [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Milwaukee, WI |  |  |
Encumbrances | 1,641 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroWVogelAvenueBuildingBMember |  |  |
Initial Cost of Land | 301 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroWVogelAvenueBuildingBMember |  |  |
Building and Improvements | 2,150 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroWVogelAvenueBuildingBMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (22)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroWVogelAvenueBuildingBMember |  |  |
Land | 302 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroWVogelAvenueBuildingBMember |  |  |
Building and improvements | 2,127 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroWVogelAvenueBuildingBMember |  |  |
Total | 2,429 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroWVogelAvenueBuildingBMember |  |  |
Accumulated depreciation 12/31/2012 | 1,021 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroWVogelAvenueBuildingBMember |  |  |
4921 S. 2nd Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Milwaukee, WI |  |  |
Initial Cost of Land | 101 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourNineTwoOneSTwoStreetMember |  |  |
Building and Improvements | 713 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourNineTwoOneSTwoStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (196)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourNineTwoOneSTwoStreetMember |  |  |
Land | 58 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourNineTwoOneSTwoStreetMember |  |  |
Building and improvements | 560 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourNineTwoOneSTwoStreetMember |  |  |
Total | 618 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourNineTwoOneSTwoStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 278 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourNineTwoOneSTwoStreetMember |  |  |
1500 Peebles Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Richland Center, WI |  |  |
Initial Cost of Land | 1,577 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveZeroZeroPeeblesDriveMember |  |  |
Building and Improvements | 1,018 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveZeroZeroPeeblesDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (278)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveZeroZeroPeeblesDriveMember |  |  |
Land | 1,528 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveZeroZeroPeeblesDriveMember |  |  |
Building and improvements | 789 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveZeroZeroPeeblesDriveMember |  |  |
Total | 2,317 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveZeroZeroPeeblesDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 697 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveZeroZeroPeeblesDriveMember |  |  |
16600 West Glendale Ave [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | New Berlin, WI |  |  |
Encumbrances | 2,317 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixSixZeroZeroWestGlendaleAvenueMember |  |  |
Initial Cost of Land | 704 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixSixZeroZeroWestGlendaleAvenueMember |  |  |
Building and Improvements | 1,923 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixSixZeroZeroWestGlendaleAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 933 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixSixZeroZeroWestGlendaleAvenueMember |  |  |
Land | 715 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixSixZeroZeroWestGlendaleAvenueMember |  |  |
Building and improvements | 2,845 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixSixZeroZeroWestGlendaleAvenueMember |  |  |
Total | 3,560 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixSixZeroZeroWestGlendaleAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 1,494 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixSixZeroZeroWestGlendaleAvenueMember |  |  |
2485 Commerce Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | New Berlin, WI |  |  |
Encumbrances | 1,386 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourEightFiveCommerceDriveMember |  |  |
Initial Cost of Land | 483 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourEightFiveCommerceDriveMember |  |  |
Building and Improvements | 1,516 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourEightFiveCommerceDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 131 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourEightFiveCommerceDriveMember |  |  |
Land | 491 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourEightFiveCommerceDriveMember |  |  |
Building and improvements | 1,639 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourEightFiveCommerceDriveMember |  |  |
Total | 2,130 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourEightFiveCommerceDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 743 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourEightFiveCommerceDriveMember |  |  |
14518 Whittaker Way [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Menomonee Falls, WI |  |  |
Initial Cost of Land | 437 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourFiveOneEightWhittakerWayMember |  |  |
Building and Improvements | 1,082 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourFiveOneEightWhittakerWayMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 382 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourFiveOneEightWhittakerWayMember |  |  |
Land | 445 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourFiveOneEightWhittakerWayMember |  |  |
Building and improvements | 1,456 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourFiveOneEightWhittakerWayMember |  |  |
Total | 1,901 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourFiveOneEightWhittakerWayMember |  |  |
Accumulated depreciation 12/31/2012 | 538 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourFiveOneEightWhittakerWayMember |  |  |
N58W15380 Shawn Circle [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Menomonee Falls, WI |  |  |
Initial Cost of Land | 1,188 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NfiveEightWoneFiveThreeEightZeroShawnCircleMemberMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 16,931 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NfiveEightWoneFiveThreeEightZeroShawnCircleMemberMember |  |  |
Land | 1,204 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NfiveEightWoneFiveThreeEightZeroShawnCircleMemberMember |  |  |
Building and improvements | 16,915 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NfiveEightWoneFiveThreeEightZeroShawnCircleMemberMember |  |  |
Total | 18,119 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NfiveEightWoneFiveThreeEightZeroShawnCircleMemberMember |  |  |
Accumulated depreciation 12/31/2012 | 3,014 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NfiveEightWoneFiveThreeEightZeroShawnCircleMemberMember |  |  |
6201 West 111th Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Bloomington, MN |  |  |
Encumbrances | 3,293 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixTwoZeroOneWestOneOneOneThStreetMember |  |  |
Initial Cost of Land | 1,358 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixTwoZeroOneWestOneOneOneThStreetMember |  |  |
Building and Improvements | 8,622 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixTwoZeroOneWestOneOneOneThStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 13,466 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixTwoZeroOneWestOneOneOneThStreetMember |  |  |
Land | 1,519 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixTwoZeroOneWestOneOneOneThStreetMember |  |  |
Building and improvements | 21,927 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixTwoZeroOneWestOneOneOneThStreetMember |  |  |
Total | 23,446 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixTwoZeroOneWestOneOneOneThStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 11,065 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixTwoZeroOneWestOneOneOneThStreetMember |  |  |
7251-7267 Washington Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Edina, MN |  |  |
Initial Cost of Land | 129 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenTwoFiveOneAndSevenTwoSixSevenWashingtonAvenueMember |  |  |
Building and Improvements | 382 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenTwoFiveOneAndSevenTwoSixSevenWashingtonAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 871 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenTwoFiveOneAndSevenTwoSixSevenWashingtonAvenueMember |  |  |
Land | 182 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenTwoFiveOneAndSevenTwoSixSevenWashingtonAvenueMember |  |  |
Building and improvements | 1,200 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenTwoFiveOneAndSevenTwoSixSevenWashingtonAvenueMember |  |  |
Total | 1,382 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenTwoFiveOneAndSevenTwoSixSevenWashingtonAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 842 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenTwoFiveOneAndSevenTwoSixSevenWashingtonAvenueMember |  |  |
7301-7325 Washington Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Edina, MN |  |  |
Initial Cost of Land | 174 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThreeZeroOneAndSevenThreeTwoFiveWashingtonAvenueMember |  |  |
Building and Improvements | 391 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThreeZeroOneAndSevenThreeTwoFiveWashingtonAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 70 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThreeZeroOneAndSevenThreeTwoFiveWashingtonAvenueMember |  |  |
Land | 193 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThreeZeroOneAndSevenThreeTwoFiveWashingtonAvenueMember |  |  |
Building and improvements | 442 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThreeZeroOneAndSevenThreeTwoFiveWashingtonAvenueMember |  |  |
Total | 635 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThreeZeroOneAndSevenThreeTwoFiveWashingtonAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 113 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThreeZeroOneAndSevenThreeTwoFiveWashingtonAvenueMember |  |  |
7101 Winnetka Avenue North [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Brooklyn Park, MN |  |  |
Encumbrances | 5,629 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenOneZeroOneWinnetkaAvenueNorthMember |  |  |
Initial Cost of Land | 2,195 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenOneZeroOneWinnetkaAvenueNorthMember |  |  |
Building and Improvements | 6,084 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenOneZeroOneWinnetkaAvenueNorthMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 3,996 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenOneZeroOneWinnetkaAvenueNorthMember |  |  |
Land | 2,228 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenOneZeroOneWinnetkaAvenueNorthMember |  |  |
Building and improvements | 10,047 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenOneZeroOneWinnetkaAvenueNorthMember |  |  |
Total | 12,275 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenOneZeroOneWinnetkaAvenueNorthMember |  |  |
Accumulated depreciation 12/31/2012 | 7,107 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenOneZeroOneWinnetkaAvenueNorthMember |  |  |
9901 West 74th Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Eden Prairie, MN |  |  |
Encumbrances | 3,303 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineNineZeroOneWestSevenFourThStreetMember |  |  |
Initial Cost of Land | 621 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineNineZeroOneWestSevenFourThStreetMember |  |  |
Building and Improvements | 3,289 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineNineZeroOneWestSevenFourThStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 3,291 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineNineZeroOneWestSevenFourThStreetMember |  |  |
Land | 639 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineNineZeroOneWestSevenFourThStreetMember |  |  |
Building and improvements | 6,562 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineNineZeroOneWestSevenFourThStreetMember |  |  |
Total | 7,201 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineNineZeroOneWestSevenFourThStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 5,599 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineNineZeroOneWestSevenFourThStreetMember |  |  |
1030 Lone Oak Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Eagan, MN |  |  |
Encumbrances | 2,553 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroThreeZeroLoneOakRoadMember |  |  |
Initial Cost of Land | 456 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroThreeZeroLoneOakRoadMember |  |  |
Building and Improvements | 2,703 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroThreeZeroLoneOakRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 764 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroThreeZeroLoneOakRoadMember |  |  |
Land | 456 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroThreeZeroLoneOakRoadMember |  |  |
Building and improvements | 3,467 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroThreeZeroLoneOakRoadMember |  |  |
Total | 3,923 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroThreeZeroLoneOakRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 1,588 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroThreeZeroLoneOakRoadMember |  |  |
1060 Lone Oak Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Eagan, MN |  |  |
Encumbrances | 3,216 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroSixZeroLoneOakRoadMember |  |  |
Initial Cost of Land | 624 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroSixZeroLoneOakRoadMember |  |  |
Building and Improvements | 3,700 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroSixZeroLoneOakRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 616 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroSixZeroLoneOakRoadMember |  |  |
Land | 624 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroSixZeroLoneOakRoadMember |  |  |
Building and improvements | 4,316 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroSixZeroLoneOakRoadMember |  |  |
Total | 4,940 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroSixZeroLoneOakRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 2,115 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroSixZeroLoneOakRoadMember |  |  |
5400 Nathan Lane [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Plymouth, MN |  |  |
Encumbrances | 2,826 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourZeroZeroNathanLaneMember |  |  |
Initial Cost of Land | 749 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourZeroZeroNathanLaneMember |  |  |
Building and Improvements | 4,461 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourZeroZeroNathanLaneMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 951 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourZeroZeroNathanLaneMember |  |  |
Land | 757 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourZeroZeroNathanLaneMember |  |  |
Building and improvements | 5,404 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourZeroZeroNathanLaneMember |  |  |
Total | 6,161 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourZeroZeroNathanLaneMember |  |  |
Accumulated depreciation 12/31/2012 | 2,660 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourZeroZeroNathanLaneMember |  |  |
6655 Wedgewood Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Maple Grove, MN |  |  |
Initial Cost of Land | 1,466 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSixFiveFiveWedgewoodRoadMember |  |  |
Building and Improvements | 8,342 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSixFiveFiveWedgewoodRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 4,267 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSixFiveFiveWedgewoodRoadMember |  |  |
Land | 1,466 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSixFiveFiveWedgewoodRoadMember |  |  |
Building and improvements | 12,609 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSixFiveFiveWedgewoodRoadMember |  |  |
Total | 14,075 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSixFiveFiveWedgewoodRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 5,446 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSixFiveFiveWedgewoodRoadMember |  |  |
10120 W 76th Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Eden Prairie, MN |  |  |
Initial Cost of Land | 315 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroOneTwoZeroWSevenSixThStreetMember |  |  |
Building and Improvements | 1,804 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroOneTwoZeroWSevenSixThStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,884 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroOneTwoZeroWSevenSixThStreetMember |  |  |
Land | 315 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroOneTwoZeroWSevenSixThStreetMember |  |  |
Building and improvements | 3,688 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroOneTwoZeroWSevenSixThStreetMember |  |  |
Total | 4,003 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroOneTwoZeroWSevenSixThStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 1,978 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroOneTwoZeroWSevenSixThStreetMember |  |  |
12155 Nicollet Ave. [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Burnsville, MN |  |  |
Initial Cost of Land | 286 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoOneFiveFiveNicolletAveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,809 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoOneFiveFiveNicolletAveMember |  |  |
Land | 288 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoOneFiveFiveNicolletAveMember |  |  |
Building and improvements | 1,807 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoOneFiveFiveNicolletAveMember |  |  |
Total | 2,095 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoOneFiveFiveNicolletAveMember |  |  |
Accumulated depreciation 12/31/2012 | 829 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoOneFiveFiveNicolletAveMember |  |  |
4100 Peavey Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Chaska, MN |  |  |
Initial Cost of Land | 277 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourOneZeroZeroPeaveyRoadMember |  |  |
Building and Improvements | 2,261 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourOneZeroZeroPeaveyRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 779 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourOneZeroZeroPeaveyRoadMember |  |  |
Land | 277 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourOneZeroZeroPeaveyRoadMember |  |  |
Building and improvements | 3,040 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourOneZeroZeroPeaveyRoadMember |  |  |
Total | 3,317 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourOneZeroZeroPeaveyRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 1,332 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourOneZeroZeroPeaveyRoadMember |  |  |
5205 Highway 169 [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Plymouth, MN |  |  |
Initial Cost of Land | 446 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveTwoZeroFiveHighwayOneSixNineMember |  |  |
Building and Improvements | 2,525 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveTwoZeroFiveHighwayOneSixNineMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 891 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveTwoZeroFiveHighwayOneSixNineMember |  |  |
Land | 578 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveTwoZeroFiveHighwayOneSixNineMember |  |  |
Building and improvements | 3,284 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveTwoZeroFiveHighwayOneSixNineMember |  |  |
Total | 3,862 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveTwoZeroFiveHighwayOneSixNineMember |  |  |
Accumulated depreciation 12/31/2012 | 1,526 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveTwoZeroFiveHighwayOneSixNineMember |  |  |
7100-7198 Shady Oak Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Eden Prairie, MN |  |  |
Encumbrances | 4,569 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenOneZeroZeroAndSevenOneNineEightShadyOakRoadMember |  |  |
Initial Cost of Land | 715 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenOneZeroZeroAndSevenOneNineEightShadyOakRoadMember |  |  |
Building and Improvements | 4,054 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenOneZeroZeroAndSevenOneNineEightShadyOakRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 2,252 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenOneZeroZeroAndSevenOneNineEightShadyOakRoadMember |  |  |
Land | 736 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenOneZeroZeroAndSevenOneNineEightShadyOakRoadMember |  |  |
Building and improvements | 6,285 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenOneZeroZeroAndSevenOneNineEightShadyOakRoadMember |  |  |
Total | 7,021 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenOneZeroZeroAndSevenOneNineEightShadyOakRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 2,484 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenOneZeroZeroAndSevenOneNineEightShadyOakRoadMember |  |  |
7500-7546 Washington Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Eden Prairie, MN |  |  |
Initial Cost of Land | 229 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFiveZeroZeroAndSevenFiveFourSixWashingtonSquareMember |  |  |
Building and Improvements | 1,300 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFiveZeroZeroAndSevenFiveFourSixWashingtonSquareMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 881 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFiveZeroZeroAndSevenFiveFourSixWashingtonSquareMember |  |  |
Land | 235 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFiveZeroZeroAndSevenFiveFourSixWashingtonSquareMember |  |  |
Building and improvements | 2,175 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFiveZeroZeroAndSevenFiveFourSixWashingtonSquareMember |  |  |
Total | 2,410 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFiveZeroZeroAndSevenFiveFourSixWashingtonSquareMember |  |  |
Accumulated depreciation 12/31/2012 | 928 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFiveZeroZeroAndSevenFiveFourSixWashingtonSquareMember |  |  |
7550-7586 Washington Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Eden Prairie, MN |  |  |
Initial Cost of Land | 153 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFiveFiveZeroAndSevenFiveEightSixWashingtonSquareMember |  |  |
Building and Improvements | 867 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFiveFiveZeroAndSevenFiveEightSixWashingtonSquareMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 290 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFiveFiveZeroAndSevenFiveEightSixWashingtonSquareMember |  |  |
Land | 157 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFiveFiveZeroAndSevenFiveEightSixWashingtonSquareMember |  |  |
Building and improvements | 1,153 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFiveFiveZeroAndSevenFiveEightSixWashingtonSquareMember |  |  |
Total | 1,310 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFiveFiveZeroAndSevenFiveEightSixWashingtonSquareMember |  |  |
Accumulated depreciation 12/31/2012 | 511 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFiveFiveZeroAndSevenFiveEightSixWashingtonSquareMember |  |  |
5240-5300 Valley Industrial Blvd S [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Shakopee, MN |  |  |
Encumbrances | 2,450 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveTwoFourZeroAndFiveThreeZeroZeroValleyIndustrialBlvdSMember |  |  |
Initial Cost of Land | 362 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveTwoFourZeroAndFiveThreeZeroZeroValleyIndustrialBlvdSMember |  |  |
Building and Improvements | 2,049 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveTwoFourZeroAndFiveThreeZeroZeroValleyIndustrialBlvdSMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,215 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveTwoFourZeroAndFiveThreeZeroZeroValleyIndustrialBlvdSMember |  |  |
Land | 371 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveTwoFourZeroAndFiveThreeZeroZeroValleyIndustrialBlvdSMember |  |  |
Building and improvements | 3,255 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveTwoFourZeroAndFiveThreeZeroZeroValleyIndustrialBlvdSMember |  |  |
Total | 3,626 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveTwoFourZeroAndFiveThreeZeroZeroValleyIndustrialBlvdSMember |  |  |
Accumulated depreciation 12/31/2012 | 1,215 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveTwoFourZeroAndFiveThreeZeroZeroValleyIndustrialBlvdSMember |  |  |
500-530 Kasota Avenue SE [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Minneapolis, MN |  |  |
Initial Cost of Land | 415 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroZeroAndFiveThreeZeroKasotaAvenueSeMember |  |  |
Building and Improvements | 2,354 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroZeroAndFiveThreeZeroKasotaAvenueSeMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,276 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroZeroAndFiveThreeZeroKasotaAvenueSeMember |  |  |
Land | 434 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroZeroAndFiveThreeZeroKasotaAvenueSeMember |  |  |
Building and improvements | 3,611 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroZeroAndFiveThreeZeroKasotaAvenueSeMember |  |  |
Total | 4,045 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroZeroAndFiveThreeZeroKasotaAvenueSeMember |  |  |
Accumulated depreciation 12/31/2012 | 1,467 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroZeroAndFiveThreeZeroKasotaAvenueSeMember |  |  |
2530-2570 Kasota Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | St. Paul, MN |  |  |
Initial Cost of Land | 407 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFiveThreeZeroAndTwoFiveSevenZeroKasotaAvenueMember |  |  |
Building and Improvements | 2,308 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFiveThreeZeroAndTwoFiveSevenZeroKasotaAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 964 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFiveThreeZeroAndTwoFiveSevenZeroKasotaAvenueMember |  |  |
Land | 441 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFiveThreeZeroAndTwoFiveSevenZeroKasotaAvenueMember |  |  |
Building and improvements | 3,238 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFiveThreeZeroAndTwoFiveSevenZeroKasotaAvenueMember |  |  |
Total | 3,679 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFiveThreeZeroAndTwoFiveSevenZeroKasotaAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 1,315 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFiveThreeZeroAndTwoFiveSevenZeroKasotaAvenueMember |  |  |
5775 12th Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Shakopee, MN |  |  |
Encumbrances | 3,965 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveSevenSevenFiveOneTwoThAvenueMember |  |  |
Initial Cost of Land | 590 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveSevenSevenFiveOneTwoThAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 5,279 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveSevenSevenFiveOneTwoThAvenueMember |  |  |
Land | 590 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveSevenSevenFiveOneTwoThAvenueMember |  |  |
Building and improvements | 5,279 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveSevenSevenFiveOneTwoThAvenueMember |  |  |
Total | 5,869 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveSevenSevenFiveOneTwoThAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 2,103 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveSevenSevenFiveOneTwoThAvenueMember |  |  |
1157 Valley Park Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Shakopee, MN |  |  |
Encumbrances | 3,969 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFiveSevenValleyParkDriveMember |  |  |
Initial Cost of Land | 760 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFiveSevenValleyParkDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 6,803 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFiveSevenValleyParkDriveMember |  |  |
Land | 888 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFiveSevenValleyParkDriveMember |  |  |
Building and improvements | 6,675 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFiveSevenValleyParkDriveMember |  |  |
Total | 7,563 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFiveSevenValleyParkDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 2,579 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFiveSevenValleyParkDriveMember |  |  |
9600 West 76th Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Eden Prairie, MN |  |  |
Encumbrances | 2,325 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSixZeroZeroWestSevenSixThStreetMember |  |  |
Initial Cost of Land | 1,000 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSixZeroZeroWestSevenSixThStreetMember |  |  |
Building and Improvements | 2,450 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSixZeroZeroWestSevenSixThStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 483 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSixZeroZeroWestSevenSixThStreetMember |  |  |
Land | 1,034 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSixZeroZeroWestSevenSixThStreetMember |  |  |
Building and improvements | 2,899 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSixZeroZeroWestSevenSixThStreetMember |  |  |
Total | 3,933 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSixZeroZeroWestSevenSixThStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 968 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSixZeroZeroWestSevenSixThStreetMember |  |  |
9700 West 76th Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Eden Prairie, MN |  |  |
Encumbrances | 3,151 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSevenZeroZeroWestSevenSixThStreetMember |  |  |
Initial Cost of Land | 1,000 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSevenZeroZeroWestSevenSixThStreetMember |  |  |
Building and Improvements | 2,709 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSevenZeroZeroWestSevenSixThStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,007 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSevenZeroZeroWestSevenSixThStreetMember |  |  |
Land | 1,038 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSevenZeroZeroWestSevenSixThStreetMember |  |  |
Building and improvements | 3,678 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSevenZeroZeroWestSevenSixThStreetMember |  |  |
Total | 4,716 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSevenZeroZeroWestSevenSixThStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 1,284 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSevenZeroZeroWestSevenSixThStreetMember |  |  |
7600 69th Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Greenfield, MN |  |  |
Initial Cost of Land | 1,500 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenSixZeroZeroSixNineThAvenueMember |  |  |
Building and Improvements | 8,328 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenSixZeroZeroSixNineThAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,391 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenSixZeroZeroSixNineThAvenueMember |  |  |
Land | 1,510 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenSixZeroZeroSixNineThAvenueMember |  |  |
Building and improvements | 9,709 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenSixZeroZeroSixNineThAvenueMember |  |  |
Total | 11,219 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenSixZeroZeroSixNineThAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 3,571 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenSixZeroZeroSixNineThAvenueMember |  |  |
5017 Boone Avenue North [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | New Hope, MN |  |  |
Initial Cost of Land | 1,000 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroOneSevenBooneAvenueNorthMember |  |  |
Building and Improvements | 1,599 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroOneSevenBooneAvenueNorthMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (6)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroOneSevenBooneAvenueNorthMember |  |  |
Land | 1,009 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroOneSevenBooneAvenueNorthMember |  |  |
Building and improvements | 1,584 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroOneSevenBooneAvenueNorthMember |  |  |
Total | 2,593 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroOneSevenBooneAvenueNorthMember |  |  |
Accumulated depreciation 12/31/2012 | 813 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroOneSevenBooneAvenueNorthMember |  |  |
2300 West Highway 13 [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Burnsville, MN |  |  |
Initial Cost of Land | 2,517 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroZeroWestHighwayOneThreeMember |  |  |
Building and Improvements | 6,069 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroZeroWestHighwayOneThreeMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (1,651)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroZeroWestHighwayOneThreeMember |  |  |
Land | 1,296 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroZeroWestHighwayOneThreeMember |  |  |
Building and improvements | 5,639 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroZeroWestHighwayOneThreeMember |  |  |
Total | 6,935 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroZeroWestHighwayOneThreeMember |  |  |
Accumulated depreciation 12/31/2012 | 3,449 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroZeroWestHighwayOneThreeMember |  |  |
1087 Park Place [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Shakopee, MN |  |  |
Encumbrances | 4,218 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroEightSevenParkPlaceMember |  |  |
Initial Cost of Land | 1,195 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroEightSevenParkPlaceMember |  |  |
Building and Improvements | 4,891 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroEightSevenParkPlaceMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (409)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroEightSevenParkPlaceMember |  |  |
Land | 1,198 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroEightSevenParkPlaceMember |  |  |
Building and improvements | 4,479 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroEightSevenParkPlaceMember |  |  |
Total | 5,677 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroEightSevenParkPlaceMember |  |  |
Accumulated depreciation 12/31/2012 | 1,091 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroEightSevenParkPlaceMember |  |  |
5391 12th Avenue SE [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Shakopee, MN |  |  |
Encumbrances | 4,381 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThreeNineOneOneTwoThAvenueSeMember |  |  |
Initial Cost of Land | 1,392 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThreeNineOneOneTwoThAvenueSeMember |  |  |
Building and Improvements | 8,149 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThreeNineOneOneTwoThAvenueSeMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (495)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThreeNineOneOneTwoThAvenueSeMember |  |  |
Land | 1,395 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThreeNineOneOneTwoThAvenueSeMember |  |  |
Building and improvements | 7,651 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThreeNineOneOneTwoThAvenueSeMember |  |  |
Total | 9,046 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThreeNineOneOneTwoThAvenueSeMember |  |  |
Accumulated depreciation 12/31/2012 | 1,915 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThreeNineOneOneTwoThAvenueSeMember |  |  |
4701 Valley Industrial Blvd S [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Shakopee, MN |  |  |
Encumbrances | 5,483 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenZeroOneValleyIndustrialBlvdSMember |  |  |
Initial Cost of Land | 1,296 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenZeroOneValleyIndustrialBlvdSMember |  |  |
Building and Improvements | 7,157 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenZeroOneValleyIndustrialBlvdSMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (337)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenZeroOneValleyIndustrialBlvdSMember |  |  |
Land | 1,299 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenZeroOneValleyIndustrialBlvdSMember |  |  |
Building and improvements | 6,817 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenZeroOneValleyIndustrialBlvdSMember |  |  |
Total | 8,116 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenZeroOneValleyIndustrialBlvdSMember |  |  |
Accumulated depreciation 12/31/2012 | 2,477 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenZeroOneValleyIndustrialBlvdSMember |  |  |
6455 City West Parkway [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Eden Prairie, MN |  |  |
Initial Cost of Land | 659 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFourFiveFiveCityWestParkwayMember |  |  |
Building and Improvements | 3,189 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFourFiveFiveCityWestParkwayMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 949 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFourFiveFiveCityWestParkwayMember |  |  |
Land | 665 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFourFiveFiveCityWestParkwayMember |  |  |
Building and improvements | 4,132 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFourFiveFiveCityWestParkwayMember |  |  |
Total | 4,797 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFourFiveFiveCityWestParkwayMember |  |  |
Accumulated depreciation 12/31/2012 | 974 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFourFiveFiveCityWestParkwayMember |  |  |
7035 Winnetka Avene North [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Brooklyn Park, MN |  |  |
Encumbrances | 4,076 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenZeroThreeFiveWinnetkaAvenueNorthMember |  |  |
Initial Cost of Land | 1,275 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenZeroThreeFiveWinnetkaAvenueNorthMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 6,492 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenZeroThreeFiveWinnetkaAvenueNorthMember |  |  |
Land | 1,343 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenZeroThreeFiveWinnetkaAvenueNorthMember |  |  |
Building and improvements | 6,424 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenZeroThreeFiveWinnetkaAvenueNorthMember |  |  |
Total | 7,767 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenZeroThreeFiveWinnetkaAvenueNorthMember |  |  |
Accumulated depreciation 12/31/2012 | 1,245 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenZeroThreeFiveWinnetkaAvenueNorthMember |  |  |
139 Eva Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | St. Paul, MN |  |  |
Initial Cost of Land | 2,132 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeNineEvaStreetMember |  |  |
Building and Improvements | 3,105 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeNineEvaStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (286)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeNineEvaStreetMember |  |  |
Land | 2,175 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeNineEvaStreetMember |  |  |
Building and improvements | 2,776 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeNineEvaStreetMember |  |  |
Total | 4,951 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeNineEvaStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 560 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeNineEvaStreetMember |  |  |
21900 Dodd Boulevard [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Lakeville, MN |  |  |
Encumbrances | 9,031 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneNineZeroZeroDoddBoulevardMember |  |  |
Initial Cost of Land | 2,289 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneNineZeroZeroDoddBoulevardMember |  |  |
Building and Improvements | 7,952 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneNineZeroZeroDoddBoulevardMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 0 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneNineZeroZeroDoddBoulevardMember |  |  |
Land | 2,289 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneNineZeroZeroDoddBoulevardMember |  |  |
Building and improvements | 7,952 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneNineZeroZeroDoddBoulevardMember |  |  |
Total | 10,241 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneNineZeroZeroDoddBoulevardMember |  |  |
Accumulated depreciation 12/31/2012 | 1,692 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneNineZeroZeroDoddBoulevardMember |  |  |
Three Hundred Seventy Five Rivertown Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Woodbury, MN |  |  |
Encumbrances | 7,058 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredSeventyFiveRivertownDriveMember |  |  |
Initial Cost of Land | 2,635 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredSeventyFiveRivertownDriveMember |  |  |
Building and Improvements | 8,157 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredSeventyFiveRivertownDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 48 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredSeventyFiveRivertownDriveMember |  |  |
Land | 2,635 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredSeventyFiveRivertownDriveMember |  |  |
Building and improvements | 8,205 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredSeventyFiveRivertownDriveMember |  |  |
Total | 10,840 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredSeventyFiveRivertownDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 407 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeHundredSeventyFiveRivertownDriveMember |  |  |
Nine Hundred Thirty Five Aldrin Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Eagan, MN |  |  |
Initial Cost of Land | 2,096 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineHundredThirtyFiveAldrinDriveMember |  |  |
Building and Improvements | 7,884 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineHundredThirtyFiveAldrinDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineHundredThirtyFiveAldrinDriveMember |  |  |
Land | 2,096 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineHundredThirtyFiveAldrinDriveMember |  |  |
Building and improvements | 7,885 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineHundredThirtyFiveAldrinDriveMember |  |  |
Total | 9,981 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineHundredThirtyFiveAldrinDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 65 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineHundredThirtyFiveAldrinDriveMember |  |  |
Seven Thousand Fifty Winnetka Avenue North [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Brooklyn Park, MN |  |  |
Initial Cost of Land | 1,623 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandFiftyWinnetkaAvenueNorthMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 7,792 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandFiftyWinnetkaAvenueNorthMember |  |  |
Land | 1,632 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandFiftyWinnetkaAvenueNorthMember |  |  |
Building and improvements | 7,783 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandFiftyWinnetkaAvenueNorthMember |  |  |
Total | 9,415 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandFiftyWinnetkaAvenueNorthMember |  |  |
Seven Thousand Fifty One West Broadway [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Brooklyn Park, MN |  |  |
Initial Cost of Land | 1,275 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandFiftyOneWestBroadwayMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 5,246 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandFiftyOneWestBroadwayMember |  |  |
Land | 1,277 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandFiftyOneWestBroadwayMember |  |  |
Building and improvements | 5,244 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandFiftyOneWestBroadwayMember |  |  |
Total | 6,521 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenThousandFiftyOneWestBroadwayMember |  |  |
1621 Heil Quaker Boulevard [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Nashville, TN |  |  |
Encumbrances | 1,945 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixTwoOneHeilQuakerBoulevardMember |  |  |
Initial Cost of Land | 413 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixTwoOneHeilQuakerBoulevardMember |  |  |
Building and Improvements | 2,383 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixTwoOneHeilQuakerBoulevardMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 984 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixTwoOneHeilQuakerBoulevardMember |  |  |
Land | 430 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixTwoOneHeilQuakerBoulevardMember |  |  |
Building and improvements | 3,350 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixTwoOneHeilQuakerBoulevardMember |  |  |
Total | 3,780 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixTwoOneHeilQuakerBoulevardMember |  |  |
Accumulated depreciation 12/31/2012 | 1,594 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixTwoOneHeilQuakerBoulevardMember |  |  |
3099 Barry Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Portland, TN |  |  |
Initial Cost of Land | 418 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroNineNineBarryDriveMember |  |  |
Building and Improvements | 2,368 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroNineNineBarryDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (683)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroNineNineBarryDriveMember |  |  |
Land | 248 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroNineNineBarryDriveMember |  |  |
Building and improvements | 1,855 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroNineNineBarryDriveMember |  |  |
Total | 2,103 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroNineNineBarryDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,022 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroNineNineBarryDriveMember |  |  |
1931 Air Lane Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Nashville, TN |  |  |
Encumbrances | 2,344 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineThreeOneAirLaneDriveMember |  |  |
Initial Cost of Land | 489 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineThreeOneAirLaneDriveMember |  |  |
Building and Improvements | 2,785 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineThreeOneAirLaneDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 327 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineThreeOneAirLaneDriveMember |  |  |
Land | 493 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineThreeOneAirLaneDriveMember |  |  |
Building and improvements | 3,108 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineThreeOneAirLaneDriveMember |  |  |
Total | 3,601 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineThreeOneAirLaneDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,326 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineThreeOneAirLaneDriveMember |  |  |
4640 Cummings Park [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Nashville, TN |  |  |
Encumbrances | 2,053 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSixFourZeroCummingsParkMember |  |  |
Initial Cost of Land | 360 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSixFourZeroCummingsParkMember |  |  |
Building and Improvements | 2,040 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSixFourZeroCummingsParkMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 638 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSixFourZeroCummingsParkMember |  |  |
Land | 365 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSixFourZeroCummingsParkMember |  |  |
Building and improvements | 2,673 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSixFourZeroCummingsParkMember |  |  |
Total | 3,038 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSixFourZeroCummingsParkMember |  |  |
Accumulated depreciation 12/31/2012 | 957 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSixFourZeroCummingsParkMember |  |  |
1740 River Hills Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Nashville, TN |  |  |
Encumbrances | 2,759 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenFourZeroRiverHillsDriveMember |  |  |
Initial Cost of Land | 848 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenFourZeroRiverHillsDriveMember |  |  |
Building and Improvements | 4,383 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenFourZeroRiverHillsDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 607 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenFourZeroRiverHillsDriveMember |  |  |
Land | 888 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenFourZeroRiverHillsDriveMember |  |  |
Building and improvements | 4,950 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenFourZeroRiverHillsDriveMember |  |  |
Total | 5,838 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenFourZeroRiverHillsDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,933 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSevenFourZeroRiverHillsDriveMember |  |  |
211 Ellery Court [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Nashville, TN |  |  |
Encumbrances | 2,727 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneOneElleryCourtMember |  |  |
Initial Cost of Land | 606 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneOneElleryCourtMember |  |  |
Building and Improvements | 3,192 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneOneElleryCourtMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 349 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneOneElleryCourtMember |  |  |
Land | 616 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneOneElleryCourtMember |  |  |
Building and improvements | 3,531 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneOneElleryCourtMember |  |  |
Total | 4,147 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneOneElleryCourtMember |  |  |
Accumulated depreciation 12/31/2012 | 1,098 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneOneElleryCourtMember |  |  |
130 Maddox Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Gallatin, TN |  |  |
Encumbrances | 15,636 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeZeroMaddoxRoadMember |  |  |
Initial Cost of Land | 1,778 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeZeroMaddoxRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 23,548 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeZeroMaddoxRoadMember |  |  |
Land | 1,778 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeZeroMaddoxRoadMember |  |  |
Building and improvements | 23,548 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeZeroMaddoxRoadMember |  |  |
Total | 25,326 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeZeroMaddoxRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 3,490 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeZeroMaddoxRoadMember |  |  |
14 World's Fair Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Franklin, NJ |  |  |
Initial Cost of Land | 483 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourWorldsFairDriveMember |  |  |
Building and Improvements | 2,735 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourWorldsFairDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 717 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourWorldsFairDriveMember |  |  |
Land | 503 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourWorldsFairDriveMember |  |  |
Building and improvements | 3,432 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourWorldsFairDriveMember |  |  |
Total | 3,935 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourWorldsFairDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,490 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourWorldsFairDriveMember |  |  |
12 World's Fair Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Franklin, NJ |  |  |
Initial Cost of Land | 572 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoWorldsFairDriveMember |  |  |
Building and Improvements | 3,240 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoWorldsFairDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,071 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoWorldsFairDriveMember |  |  |
Land | 593 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoWorldsFairDriveMember |  |  |
Building and improvements | 4,290 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoWorldsFairDriveMember |  |  |
Total | 4,883 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoWorldsFairDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,887 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoWorldsFairDriveMember |  |  |
22 World's Fair Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Franklin, NJ |  |  |
Initial Cost of Land | 364 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoTwoWorldsFairDriveMember |  |  |
Building and Improvements | 2,064 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoTwoWorldsFairDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 533 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoTwoWorldsFairDriveMember |  |  |
Land | 375 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoTwoWorldsFairDriveMember |  |  |
Building and improvements | 2,586 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoTwoWorldsFairDriveMember |  |  |
Total | 2,961 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoTwoWorldsFairDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,029 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoTwoWorldsFairDriveMember |  |  |
26 World's Fair Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Franklin, NJ |  |  |
Initial Cost of Land | 361 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSixWorldsFairDriveMember |  |  |
Building and Improvements | 2,048 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSixWorldsFairDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 523 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSixWorldsFairDriveMember |  |  |
Land | 377 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSixWorldsFairDriveMember |  |  |
Building and improvements | 2,555 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSixWorldsFairDriveMember |  |  |
Total | 2,932 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSixWorldsFairDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,052 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSixWorldsFairDriveMember |  |  |
24 World's Fair Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Franklin, NJ |  |  |
Initial Cost of Land | 347 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourWorldsFairDriveMember |  |  |
Building and Improvements | 1,968 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourWorldsFairDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 490 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourWorldsFairDriveMember |  |  |
Land | 362 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourWorldsFairDriveMember |  |  |
Building and improvements | 2,443 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourWorldsFairDriveMember |  |  |
Total | 2,805 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourWorldsFairDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,040 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourWorldsFairDriveMember |  |  |
20 World's Fair Drive Lot 13 [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Sumerset, NJ |  |  |
Initial Cost of Land | 9 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroWorldsFairDriveLotOneThreeMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 2,576 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroWorldsFairDriveLotOneThreeMember |  |  |
Land | 691 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroWorldsFairDriveLotOneThreeMember |  |  |
Building and improvements | 1,894 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroWorldsFairDriveLotOneThreeMember |  |  |
Total | 2,585 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroWorldsFairDriveLotOneThreeMember |  |  |
Accumulated depreciation 12/31/2012 | 657 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroWorldsFairDriveLotOneThreeMember |  |  |
45 Route 46 [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Pine Brook, NJ |  |  |
Initial Cost of Land | 969 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveRouteFourSixMember |  |  |
Building and Improvements | 5,491 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveRouteFourSixMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 913 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveRouteFourSixMember |  |  |
Land | 978 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveRouteFourSixMember |  |  |
Building and improvements | 6,395 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveRouteFourSixMember |  |  |
Total | 7,373 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveRouteFourSixMember |  |  |
Accumulated depreciation 12/31/2012 | 2,256 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveRouteFourSixMember |  |  |
43 Route 46 [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Pine Brook, NJ |  |  |
Initial Cost of Land | 474 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThreeRouteFourSixMember |  |  |
Building and Improvements | 2,686 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThreeRouteFourSixMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 551 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThreeRouteFourSixMember |  |  |
Land | 479 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThreeRouteFourSixMember |  |  |
Building and improvements | 3,232 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThreeRouteFourSixMember |  |  |
Total | 3,711 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThreeRouteFourSixMember |  |  |
Accumulated depreciation 12/31/2012 | 1,223 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThreeRouteFourSixMember |  |  |
39 Route 46 [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Pine Brook, NJ |  |  |
Initial Cost of Land | 260 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeNineRouteFourSixMember |  |  |
Building and Improvements | 1,471 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeNineRouteFourSixMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 197 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeNineRouteFourSixMember |  |  |
Land | 262 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeNineRouteFourSixMember |  |  |
Building and improvements | 1,666 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeNineRouteFourSixMember |  |  |
Total | 1,928 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeNineRouteFourSixMember |  |  |
Accumulated depreciation 12/31/2012 | 583 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeNineRouteFourSixMember |  |  |
26 Chapin Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Pine Brook, NJ |  |  |
Initial Cost of Land | 956 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSixChapinRoadMember |  |  |
Building and Improvements | 5,415 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSixChapinRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 672 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSixChapinRoadMember |  |  |
Land | 965 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSixChapinRoadMember |  |  |
Building and improvements | 6,078 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSixChapinRoadMember |  |  |
Total | 7,043 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSixChapinRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 2,177 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSixChapinRoadMember |  |  |
30 Chapin Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Pine Brook, NJ |  |  |
Initial Cost of Land | 960 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroChapinRoadMember |  |  |
Building and Improvements | 5,440 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroChapinRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 499 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroChapinRoadMember |  |  |
Land | 969 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroChapinRoadMember |  |  |
Building and improvements | 5,930 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroChapinRoadMember |  |  |
Total | 6,899 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroChapinRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 2,080 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroChapinRoadMember |  |  |
20 Hook Mountain Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Pine Brook, NJ |  |  |
Initial Cost of Land | 1,507 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroHookMountainRoadMember |  |  |
Building and Improvements | 8,542 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroHookMountainRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 2,809 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroHookMountainRoadMember |  |  |
Land | 1,534 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroHookMountainRoadMember |  |  |
Building and improvements | 11,324 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroHookMountainRoadMember |  |  |
Total | 12,858 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroHookMountainRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 4,700 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroHookMountainRoadMember |  |  |
30 Hook Mountain Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Pine Brook, NJ |  |  |
Initial Cost of Land | 389 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroHookMountainRoadMember |  |  |
Building and Improvements | 2,206 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroHookMountainRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 539 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroHookMountainRoadMember |  |  |
Land | 396 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroHookMountainRoadMember |  |  |
Building and improvements | 2,738 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroHookMountainRoadMember |  |  |
Total | 3,134 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroHookMountainRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 977 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroHookMountainRoadMember |  |  |
16 Chapin Rod [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Pine Brook, NJ |  |  |
Initial Cost of Land | 885 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixChapinRodMember |  |  |
Building and Improvements | 5,015 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixChapinRodMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 516 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixChapinRodMember |  |  |
Land | 901 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixChapinRodMember |  |  |
Building and improvements | 5,515 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixChapinRodMember |  |  |
Total | 6,416 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixChapinRodMember |  |  |
Accumulated depreciation 12/31/2012 | 1,924 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixChapinRodMember |  |  |
20 Chapin Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Pine Brook, NJ |  |  |
Initial Cost of Land | 1,134 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroChapinRoadMember |  |  |
Building and Improvements | 6,426 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroChapinRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 598 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroChapinRoadMember |  |  |
Land | 1,154 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroChapinRoadMember |  |  |
Building and improvements | 7,004 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroChapinRoadMember |  |  |
Total | 8,158 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroChapinRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 2,383 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroChapinRoadMember |  |  |
2500 Main Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Sayreville, NJ |  |  |
Initial Cost of Land | 944 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFiveZeroZeroMainStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 4,558 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFiveZeroZeroMainStreetMember |  |  |
Land | 944 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFiveZeroZeroMainStreetMember |  |  |
Building and improvements | 4,558 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFiveZeroZeroMainStreetMember |  |  |
Total | 5,502 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFiveZeroZeroMainStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 1,319 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFiveZeroZeroMainStreetMember |  |  |
2400 Main Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Sayreville, NJ |  |  |
Initial Cost of Land | 996 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourZeroZeroMainStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 5,575 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourZeroZeroMainStreetMember |  |  |
Land | 996 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourZeroZeroMainStreetMember |  |  |
Building and improvements | 5,575 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourZeroZeroMainStreetMember |  |  |
Total | 6,571 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourZeroZeroMainStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 1,507 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourZeroZeroMainStreetMember |  |  |
309-319 Pierce Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Somerset, NJ |  |  |
Encumbrances | 3,283 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroNineAndThreeOneThreePierceStreetMember |  |  |
Initial Cost of Land | 1,300 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroNineAndThreeOneThreePierceStreetMember |  |  |
Building and Improvements | 4,628 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroNineAndThreeOneThreePierceStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,020 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroNineAndThreeOneThreePierceStreetMember |  |  |
Land | 1,309 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroNineAndThreeOneThreePierceStreetMember |  |  |
Building and improvements | 5,639 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroNineAndThreeOneThreePierceStreetMember |  |  |
Total | 6,948 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroNineAndThreeOneThreePierceStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 1,968 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroNineAndThreeOneThreePierceStreetMember |  |  |
230-240 Welsh Pool Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Exton, PA |  |  |
Initial Cost of Land | 154 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroAndTwoFourZeroWelshPoolRoadMember |  |  |
Building and Improvements | 851 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroAndTwoFourZeroWelshPoolRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 355 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroAndTwoFourZeroWelshPoolRoadMember |  |  |
Land | 170 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroAndTwoFourZeroWelshPoolRoadMember |  |  |
Building and improvements | 1,190 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroAndTwoFourZeroWelshPoolRoadMember |  |  |
Total | 1,360 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroAndTwoFourZeroWelshPoolRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 438 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroAndTwoFourZeroWelshPoolRoadMember |  |  |
254 Welsh Pool Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Exton, PA |  |  |
Initial Cost of Land | 75 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFiveFourWelshPoolRoadMember |  |  |
Building and Improvements | 418 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFiveFourWelshPoolRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 206 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFiveFourWelshPoolRoadMember |  |  |
Land | 91 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFiveFourWelshPoolRoadMember |  |  |
Building and improvements | 608 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFiveFourWelshPoolRoadMember |  |  |
Total | 699 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFiveFourWelshPoolRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 255 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFiveFourWelshPoolRoadMember |  |  |
243-251 Welsh Pool Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Exton, PA |  |  |
Initial Cost of Land | 144 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourThreeToTwoFiveOneWelshPoolRoadMember |  |  |
Building and Improvements | 796 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourThreeToTwoFiveOneWelshPoolRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 441 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourThreeToTwoFiveOneWelshPoolRoadMember |  |  |
Land | 159 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourThreeToTwoFiveOneWelshPoolRoadMember |  |  |
Building and improvements | 1,222 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourThreeToTwoFiveOneWelshPoolRoadMember |  |  |
Total | 1,381 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourThreeToTwoFiveOneWelshPoolRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 446 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourThreeToTwoFiveOneWelshPoolRoadMember |  |  |
151-161 Philips Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Exton, PA |  |  |
Initial Cost of Land | 191 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveOneAndOneSixOnePhilipsRoadMember |  |  |
Building and Improvements | 1,059 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveOneAndOneSixOnePhilipsRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 345 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveOneAndOneSixOnePhilipsRoadMember |  |  |
Land | 229 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveOneAndOneSixOnePhilipsRoadMember |  |  |
Building and improvements | 1,366 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveOneAndOneSixOnePhilipsRoadMember |  |  |
Total | 1,595 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveOneAndOneSixOnePhilipsRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 553 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveOneAndOneSixOnePhilipsRoadMember |  |  |
216 Philips Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Exton, PA |  |  |
Initial Cost of Land | 199 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneSixPhilipsRoadMember |  |  |
Building and Improvements | 1,100 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneSixPhilipsRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 498 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneSixPhilipsRoadMember |  |  |
Land | 220 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneSixPhilipsRoadMember |  |  |
Building and improvements | 1,577 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneSixPhilipsRoadMember |  |  |
Total | 1,797 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneSixPhilipsRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 689 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneSixPhilipsRoadMember |  |  |
14 McFadden Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Palmer, PA |  |  |
Initial Cost of Land | 600 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourMcfaddenRoadMember |  |  |
Building and Improvements | 1,349 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourMcfaddenRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (274)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourMcfaddenRoadMember |  |  |
Land | 625 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourMcfaddenRoadMember |  |  |
Building and improvements | 1,050 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourMcfaddenRoadMember |  |  |
Total | 1,675 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourMcfaddenRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 265 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourMcfaddenRoadMember |  |  |
2801 Red Lion Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Philadelphia, PA |  |  |
Initial Cost of Land | 950 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightZeroOneRedLionRoadMember |  |  |
Building and Improvements | 5,916 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightZeroOneRedLionRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (51)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightZeroOneRedLionRoadMember |  |  |
Land | 964 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightZeroOneRedLionRoadMember |  |  |
Building and improvements | 5,851 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightZeroOneRedLionRoadMember |  |  |
Total | 6,815 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightZeroOneRedLionRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 2,214 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightZeroOneRedLionRoadMember |  |  |
3240 S. 78th Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Philadelphia, PA |  |  |
Initial Cost of Land | 515 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoFourZeroSSevenEightThStreetMember |  |  |
Building and Improvements | 1,245 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoFourZeroSSevenEightThStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (492)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoFourZeroSSevenEightThStreetMember |  |  |
Land | 423 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoFourZeroSSevenEightThStreetMember |  |  |
Building and improvements | 845 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoFourZeroSSevenEightThStreetMember |  |  |
Total | 1,268 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoFourZeroSSevenEightThStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 251 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeTwoFourZeroSSevenEightThStreetMember |  |  |
200 Cascade Drive, Bldg. 1 [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Allentown, PA |  |  |
Encumbrances | 16,944 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroCascadeDriveBldgOneMember |  |  |
Initial Cost of Land | 2,133 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroCascadeDriveBldgOneMember |  |  |
Building and Improvements | 17,562 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroCascadeDriveBldgOneMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 366 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroCascadeDriveBldgOneMember |  |  |
Land | 2,769 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroCascadeDriveBldgOneMember |  |  |
Building and improvements | 17,292 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroCascadeDriveBldgOneMember |  |  |
Total | 20,061 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroCascadeDriveBldgOneMember |  |  |
Accumulated depreciation 12/31/2012 | 4,972 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroCascadeDriveBldgOneMember |  |  |
200 Cascade Drive, Bldg. 2 [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Allentown, PA |  |  |
Encumbrances | 2,334 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroCascadeDriveBldgTwoMember |  |  |
Initial Cost of Land | 310 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroCascadeDriveBldgTwoMember |  |  |
Building and Improvements | 2,268 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroCascadeDriveBldgTwoMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 174 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroCascadeDriveBldgTwoMember |  |  |
Land | 316 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroCascadeDriveBldgTwoMember |  |  |
Building and improvements | 2,436 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroCascadeDriveBldgTwoMember |  |  |
Total | 2,752 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroCascadeDriveBldgTwoMember |  |  |
Accumulated depreciation 12/31/2012 | 690 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroCascadeDriveBldgTwoMember |  |  |
6300 Bristol Pike [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Levittown, PA |  |  |
Initial Cost of Land | 1,074 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixThreeZeroZeroBristolPikeMember |  |  |
Building and Improvements | 2,642 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixThreeZeroZeroBristolPikeMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (194)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixThreeZeroZeroBristolPikeMember |  |  |
Land | 964 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixThreeZeroZeroBristolPikeMember |  |  |
Building and improvements | 2,558 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixThreeZeroZeroBristolPikeMember |  |  |
Total | 3,522 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixThreeZeroZeroBristolPikeMember |  |  |
Accumulated depreciation 12/31/2012 | 1,523 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixThreeZeroZeroBristolPikeMember |  |  |
2455 Boulevard of Generals [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Norristown, PA |  |  |
Encumbrances | 3,235 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourFiveFiveBoulevardOfGeneralsMember |  |  |
Initial Cost of Land | 1,200 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourFiveFiveBoulevardOfGeneralsMember |  |  |
Building and Improvements | 4,800 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourFiveFiveBoulevardOfGeneralsMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 846 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourFiveFiveBoulevardOfGeneralsMember |  |  |
Land | 1,226 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourFiveFiveBoulevardOfGeneralsMember |  |  |
Building and improvements | 5,620 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourFiveFiveBoulevardOfGeneralsMember |  |  |
Total | 6,846 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourFiveFiveBoulevardOfGeneralsMember |  |  |
Accumulated depreciation 12/31/2012 | 1,894 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourFiveFiveBoulevardOfGeneralsMember |  |  |
1045 South Edward Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Tempe, AZ |  |  |
Initial Cost of Land | 390 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroFourFiveSouthEdwardDriveMember |  |  |
Building and Improvements | 2,160 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroFourFiveSouthEdwardDriveMember |  |  |
Land | 396 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroFourFiveSouthEdwardDriveMember |  |  |
Building and improvements | 2,524 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroFourFiveSouthEdwardDriveMember |  |  |
Total | 2,920 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroFourFiveSouthEdwardDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 877 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroFourFiveSouthEdwardDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 370 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionCarryingCosts / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroFourFiveSouthEdwardDriveMember |  |  |
50 South 56th Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Chandler, AZ |  |  |
Encumbrances | 3,766 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroSouthFiveSixStreetMember |  |  |
Initial Cost of Land | 1,206 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroSouthFiveSixStreetMember |  |  |
Building and Improvements | 3,218 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroSouthFiveSixStreetMember |  |  |
Land | 1,252 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroSouthFiveSixStreetMember |  |  |
Building and improvements | 4,534 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroSouthFiveSixStreetMember |  |  |
Total | 5,786 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroSouthFiveSixStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 1,224 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroSouthFiveSixStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,362 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionCarryingCosts / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroSouthFiveSixStreetMember |  |  |
4701 W. Jefferson [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Phoenix, AZ |  |  |
Encumbrances | 2,508 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenZeroOneWJeffersonMember |  |  |
Initial Cost of Land | 926 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenZeroOneWJeffersonMember |  |  |
Building and Improvements | 2,195 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenZeroOneWJeffersonMember |  |  |
Land | 929 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenZeroOneWJeffersonMember |  |  |
Building and improvements | 2,635 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenZeroOneWJeffersonMember |  |  |
Total | 3,564 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenZeroOneWJeffersonMember |  |  |
Accumulated depreciation 12/31/2012 | 1,418 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenZeroOneWJeffersonMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 443 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionCarryingCosts / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourSevenZeroOneWJeffersonMember |  |  |
7102 W. Roosevelt [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Phoenix, AZ |  |  |
Initial Cost of Land | 1,613 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenOneZeroTwoWRooseveltMember |  |  |
Building and Improvements | 6,451 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenOneZeroTwoWRooseveltMember |  |  |
Land | 1,620 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenOneZeroTwoWRooseveltMember |  |  |
Building and improvements | 6,788 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenOneZeroTwoWRooseveltMember |  |  |
Total | 8,408 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenOneZeroTwoWRooseveltMember |  |  |
Accumulated depreciation 12/31/2012 | 2,207 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenOneZeroTwoWRooseveltMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 344 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionCarryingCosts / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenOneZeroTwoWRooseveltMember |  |  |
4137 West Adams Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Phoenix, AZ |  |  |
Initial Cost of Land | 990 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourOneThreeSevenWestAdamsStreetMember |  |  |
Building and Improvements | 2,661 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourOneThreeSevenWestAdamsStreetMember |  |  |
Land | 1,038 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourOneThreeSevenWestAdamsStreetMember |  |  |
Building and improvements | 3,080 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourOneThreeSevenWestAdamsStreetMember |  |  |
Total | 4,118 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourOneThreeSevenWestAdamsStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 1,039 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourOneThreeSevenWestAdamsStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 467 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionCarryingCosts / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourOneThreeSevenWestAdamsStreetMember |  |  |
245 W. Lodge [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Tempe, AZ |  |  |
Initial Cost of Land | 898 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourFiveWLodgeMember |  |  |
Building and Improvements | 3,066 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourFiveWLodgeMember |  |  |
Land | 362 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourFiveWLodgeMember |  |  |
Building and improvements | 1,712 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourFiveWLodgeMember |  |  |
Total | 2,074 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourFiveWLodgeMember |  |  |
Accumulated depreciation 12/31/2012 | 710 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourFiveWLodgeMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (1,890)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionCarryingCosts / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourFiveWLodgeMember |  |  |
1590 E Riverview Dr. [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Phoenix, AZ |  |  |
Encumbrances | 4,721 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveNineZeroERiverviewDrMember |  |  |
Initial Cost of Land | 1,293 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveNineZeroERiverviewDrMember |  |  |
Building and Improvements | 5,950 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveNineZeroERiverviewDrMember |  |  |
Land | 1,292 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveNineZeroERiverviewDrMember |  |  |
Building and improvements | 6,354 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveNineZeroERiverviewDrMember |  |  |
Total | 7,646 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveNineZeroERiverviewDrMember |  |  |
Accumulated depreciation 12/31/2012 | 1,396 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveNineZeroERiverviewDrMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 403 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionCarryingCosts / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFiveNineZeroERiverviewDrMember |  |  |
14131 N. Rio Vista Blvd [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Peoria, AZ |  |  |
Initial Cost of Land | 2,563 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourOneThreeOneNRioVistaDrMember |  |  |
Building and Improvements | 9,388 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourOneThreeOneNRioVistaDrMember |  |  |
Land | 2,563 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourOneThreeOneNRioVistaDrMember |  |  |
Building and improvements | 10,489 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourOneThreeOneNRioVistaDrMember |  |  |
Total | 13,052 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourOneThreeOneNRioVistaDrMember |  |  |
Accumulated depreciation 12/31/2012 | 2,665 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourOneThreeOneNRioVistaDrMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,101 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionCarryingCosts / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourOneThreeOneNRioVistaDrMember |  |  |
8716 W. Ludlow Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Peoria, AZ |  |  |
Initial Cost of Land | 2,709 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightSevenOneSixWLudlowDriveMember |  |  |
Building and Improvements | 10,970 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightSevenOneSixWLudlowDriveMember |  |  |
Land | 2,709 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightSevenOneSixWLudlowDriveMember |  |  |
Building and improvements | 12,363 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightSevenOneSixWLudlowDriveMember |  |  |
Total | 15,072 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightSevenOneSixWLudlowDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 2,869 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightSevenOneSixWLudlowDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,393 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionCarryingCosts / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightSevenOneSixWLudlowDriveMember |  |  |
3815 W. Washington St. [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Phoenix, AZ |  |  |
Encumbrances | 3,589 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeEightOneFiveWWashingtonStreetMember |  |  |
Initial Cost of Land | 1,675 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeEightOneFiveWWashingtonStreetMember |  |  |
Building and Improvements | 4,514 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeEightOneFiveWWashingtonStreetMember |  |  |
Land | 1,719 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeEightOneFiveWWashingtonStreetMember |  |  |
Building and improvements | 4,619 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeEightOneFiveWWashingtonStreetMember |  |  |
Total | 6,338 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeEightOneFiveWWashingtonStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 959 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeEightOneFiveWWashingtonStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 149 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionCarryingCosts / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeEightOneFiveWWashingtonStreetMember |  |  |
9180 W. Buckeye Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Tolleson, AZ |  |  |
Encumbrances | 7,021 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineOneEightZeroWbuckeyeRoadMember |  |  |
Initial Cost of Land | 1,904 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineOneEightZeroWbuckeyeRoadMember |  |  |
Building and Improvements | 6,805 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineOneEightZeroWbuckeyeRoadMember |  |  |
Land | 1,923 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineOneEightZeroWbuckeyeRoadMember |  |  |
Building and improvements | 9,354 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineOneEightZeroWbuckeyeRoadMember |  |  |
Total | 11,277 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineOneEightZeroWbuckeyeRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 1,665 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineOneEightZeroWbuckeyeRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 2,568 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionCarryingCosts / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineOneEightZeroWbuckeyeRoadMember |  |  |
Eight Thousand Six Hundred Forty Four West Ludlow Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Peoria, AZ |  |  |
Initial Cost of Land | 1,726 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandSixHundredFortyFourWestLudlowDriveMember |  |  |
Building and Improvements | 7,216 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandSixHundredFortyFourWestLudlowDriveMember |  |  |
Land | 1,726 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandSixHundredFortyFourWestLudlowDriveMember |  |  |
Building and improvements | 7,216 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandSixHundredFortyFourWestLudlowDriveMember |  |  |
Total | 8,942 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandSixHundredFortyFourWestLudlowDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 43 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandSixHundredFortyFourWestLudlowDriveMember |  |  |
Eight Thousand Six Hundred Six West Ludlow Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Peoria, AZ |  |  |
Initial Cost of Land | 956 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandSixHundredSixWestLudlowDriveMember |  |  |
Building and Improvements | 2,668 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandSixHundredSixWestLudlowDriveMember |  |  |
Land | 956 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandSixHundredSixWestLudlowDriveMember |  |  |
Building and improvements | 2,668 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandSixHundredSixWestLudlowDriveMember |  |  |
Total | 3,624 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandSixHundredSixWestLudlowDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 17 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandSixHundredSixWestLudlowDriveMember |  |  |
Eight Thousand Six Hundred Seventy Nine West Ludlow Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Peoria, AZ |  |  |
Initial Cost of Land | 672 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandSixHundredSeventyNineWestLudlowDriveMember |  |  |
Building and Improvements | 2,791 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandSixHundredSeventyNineWestLudlowDriveMember |  |  |
Land | 672 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandSixHundredSeventyNineWestLudlowDriveMember |  |  |
Building and improvements | 2,791 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandSixHundredSeventyNineWestLudlowDriveMember |  |  |
Total | 3,463 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandSixHundredSeventyNineWestLudlowDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 17 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightThousandSixHundredSeventyNineWestLudlowDriveMember |  |  |
1270 West 2320 South [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | West Valley, UT |  |  |
Initial Cost of Land | 138 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenZeroWestTwoThreeTwoZeroSouthMember |  |  |
Building and Improvements | 784 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenZeroWestTwoThreeTwoZeroSouthMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 144 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenZeroWestTwoThreeTwoZeroSouthMember |  |  |
Land | 143 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenZeroWestTwoThreeTwoZeroSouthMember |  |  |
Building and improvements | 923 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenZeroWestTwoThreeTwoZeroSouthMember |  |  |
Total | 1,066 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenZeroWestTwoThreeTwoZeroSouthMember |  |  |
Accumulated depreciation 12/31/2012 | 362 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenZeroWestTwoThreeTwoZeroSouthMember |  |  |
1275 West 2240 South [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | West Valley, UT |  |  |
Initial Cost of Land | 395 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenFiveWestTwoTwoFourZeroSouthMember |  |  |
Building and Improvements | 2,241 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenFiveWestTwoTwoFourZeroSouthMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 352 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenFiveWestTwoTwoFourZeroSouthMember |  |  |
Land | 408 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenFiveWestTwoTwoFourZeroSouthMember |  |  |
Building and improvements | 2,580 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenFiveWestTwoTwoFourZeroSouthMember |  |  |
Total | 2,988 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenFiveWestTwoTwoFourZeroSouthMember |  |  |
Accumulated depreciation 12/31/2012 | 1,032 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenFiveWestTwoTwoFourZeroSouthMember |  |  |
1288 West 2240 South [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | West Valley, UT |  |  |
Initial Cost of Land | 119 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoEightEightWestTwoTwoFourZeroSouthMember |  |  |
Building and Improvements | 672 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoEightEightWestTwoTwoFourZeroSouthMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 136 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoEightEightWestTwoTwoFourZeroSouthMember |  |  |
Land | 123 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoEightEightWestTwoTwoFourZeroSouthMember |  |  |
Building and improvements | 804 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoEightEightWestTwoTwoFourZeroSouthMember |  |  |
Total | 927 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoEightEightWestTwoTwoFourZeroSouthMember |  |  |
Accumulated depreciation 12/31/2012 | 319 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoEightEightWestTwoTwoFourZeroSouthMember |  |  |
2235 South 1300 West [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | West Valley, UT |  |  |
Initial Cost of Land | 198 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoTwoThreeFiveSouthOneThreeZeroZeroWestMember |  |  |
Building and Improvements | 1,120 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoTwoThreeFiveSouthOneThreeZeroZeroWestMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 168 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoTwoThreeFiveSouthOneThreeZeroZeroWestMember |  |  |
Land | 204 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoTwoThreeFiveSouthOneThreeZeroZeroWestMember |  |  |
Building and improvements | 1,282 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoTwoThreeFiveSouthOneThreeZeroZeroWestMember |  |  |
Total | 1,486 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoTwoThreeFiveSouthOneThreeZeroZeroWestMember |  |  |
Accumulated depreciation 12/31/2012 | 512 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoTwoThreeFiveSouthOneThreeZeroZeroWestMember |  |  |
1293 West 2200 South [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | West Valley, UT |  |  |
Initial Cost of Land | 158 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoNineThreeWestTwoTwoZeroZeroSouthMember |  |  |
Building and Improvements | 896 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoNineThreeWestTwoTwoZeroZeroSouthMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 282 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoNineThreeWestTwoTwoZeroZeroSouthMember |  |  |
Land | 163 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoNineThreeWestTwoTwoZeroZeroSouthMember |  |  |
Building and improvements | 1,173 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoNineThreeWestTwoTwoZeroZeroSouthMember |  |  |
Total | 1,336 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoNineThreeWestTwoTwoZeroZeroSouthMember |  |  |
Accumulated depreciation 12/31/2012 | 471 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoNineThreeWestTwoTwoZeroZeroSouthMember |  |  |
1279 West 2200 South [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | West Valley, UT |  |  |
Initial Cost of Land | 198 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenNineWestTwoTwoZeroZeroSouthMember |  |  |
Building and Improvements | 1,120 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenNineWestTwoTwoZeroZeroSouthMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 369 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenNineWestTwoTwoZeroZeroSouthMember |  |  |
Land | 204 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenNineWestTwoTwoZeroZeroSouthMember |  |  |
Building and improvements | 1,483 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenNineWestTwoTwoZeroZeroSouthMember |  |  |
Total | 1,687 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenNineWestTwoTwoZeroZeroSouthMember |  |  |
Accumulated depreciation 12/31/2012 | 715 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenNineWestTwoTwoZeroZeroSouthMember |  |  |
1272 West 2240 South [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | West Valley, UT |  |  |
Initial Cost of Land | 336 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenTwoWestTwoTwoFourZeroSouthMember |  |  |
Building and Improvements | 1,905 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenTwoWestTwoTwoFourZeroSouthMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 410 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenTwoWestTwoTwoFourZeroSouthMember |  |  |
Land | 347 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenTwoWestTwoTwoFourZeroSouthMember |  |  |
Building and improvements | 2,304 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenTwoWestTwoTwoFourZeroSouthMember |  |  |
Total | 2,651 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenTwoWestTwoTwoFourZeroSouthMember |  |  |
Accumulated depreciation 12/31/2012 | 966 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenTwoWestTwoTwoFourZeroSouthMember |  |  |
1149 West 2240 South [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | West Valley, UT |  |  |
Initial Cost of Land | 217 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFourNineWestTwoTwoFourZeroSouthMember |  |  |
Building and Improvements | 1,232 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFourNineWestTwoTwoFourZeroSouthMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 325 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFourNineWestTwoTwoFourZeroSouthMember |  |  |
Land | 225 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFourNineWestTwoTwoFourZeroSouthMember |  |  |
Building and improvements | 1,549 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFourNineWestTwoTwoFourZeroSouthMember |  |  |
Total | 1,774 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFourNineWestTwoTwoFourZeroSouthMember |  |  |
Accumulated depreciation 12/31/2012 | 620 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFourNineWestTwoTwoFourZeroSouthMember |  |  |
1142 West 2320 South [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | West Valley, UT |  |  |
Initial Cost of Land | 217 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFourTwoWestTwoThreeTwoZeroSouthMember |  |  |
Building and Improvements | 1,232 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFourTwoWestTwoThreeTwoZeroSouthMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 260 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFourTwoWestTwoThreeTwoZeroSouthMember |  |  |
Land | 225 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFourTwoWestTwoThreeTwoZeroSouthMember |  |  |
Building and improvements | 1,484 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFourTwoWestTwoThreeTwoZeroSouthMember |  |  |
Total | 1,709 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFourTwoWestTwoThreeTwoZeroSouthMember |  |  |
Accumulated depreciation 12/31/2012 | 571 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFourTwoWestTwoThreeTwoZeroSouthMember |  |  |
1152 West 2240 South [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | West Valley, UT |  |  |
Initial Cost of Land | 1,652 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFiveTwoWestTwoTwoFourZeroSouthMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 2,323 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFiveTwoWestTwoTwoFourZeroSouthMember |  |  |
Land | 669 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFiveTwoWestTwoTwoFourZeroSouthMember |  |  |
Building and improvements | 3,306 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFiveTwoWestTwoTwoFourZeroSouthMember |  |  |
Total | 3,975 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFiveTwoWestTwoTwoFourZeroSouthMember |  |  |
Accumulated depreciation 12/31/2012 | 1,190 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneFiveTwoWestTwoTwoFourZeroSouthMember |  |  |
2323 South 900 W [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Salt Lake City, UT |  |  |
Initial Cost of Land | 886 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeTwoThreeSouthNineZeroZeroWMember |  |  |
Building and Improvements | 2,995 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeTwoThreeSouthNineZeroZeroWMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (3)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeTwoThreeSouthNineZeroZeroWMember |  |  |
Land | 898 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeTwoThreeSouthNineZeroZeroWMember |  |  |
Building and improvements | 2,980 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeTwoThreeSouthNineZeroZeroWMember |  |  |
Total | 3,878 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeTwoThreeSouthNineZeroZeroWMember |  |  |
Accumulated depreciation 12/31/2012 | 1,388 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeTwoThreeSouthNineZeroZeroWMember |  |  |
1815-1957 South 4650 West [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Salt Lake City, UT |  |  |
Encumbrances | 6,983 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightOneFiveToOneNineFiveSevenSouthFourSixFiveZeroWestMember |  |  |
Initial Cost of Land | 1,707 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightOneFiveToOneNineFiveSevenSouthFourSixFiveZeroWestMember |  |  |
Building and Improvements | 10,873 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightOneFiveToOneNineFiveSevenSouthFourSixFiveZeroWestMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 541 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightOneFiveToOneNineFiveSevenSouthFourSixFiveZeroWestMember |  |  |
Land | 1,713 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightOneFiveToOneNineFiveSevenSouthFourSixFiveZeroWestMember |  |  |
Building and improvements | 11,408 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightOneFiveToOneNineFiveSevenSouthFourSixFiveZeroWestMember |  |  |
Total | 13,121 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightOneFiveToOneNineFiveSevenSouthFourSixFiveZeroWestMember |  |  |
Accumulated depreciation 12/31/2012 | 3,065 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightOneFiveToOneNineFiveSevenSouthFourSixFiveZeroWestMember |  |  |
2100 Alexander Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | West Valley, UT |  |  |
Initial Cost of Land | 376 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneZeroZeroAlexanderStreetMember |  |  |
Building and Improvements | 1,670 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneZeroZeroAlexanderStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 319 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneZeroZeroAlexanderStreetMember |  |  |
Land | 376 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneZeroZeroAlexanderStreetMember |  |  |
Building and improvements | 1,989 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneZeroZeroAlexanderStreetMember |  |  |
Total | 2,365 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneZeroZeroAlexanderStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 518 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneZeroZeroAlexanderStreetMember |  |  |
2064 Alexander Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | West Valley, UT |  |  |
Initial Cost of Land | 864 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroSixFourAlexanderStreetMember |  |  |
Building and Improvements | 2,771 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroSixFourAlexanderStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 83 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroSixFourAlexanderStreetMember |  |  |
Land | 869 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroSixFourAlexanderStreetMember |  |  |
Building and improvements | 2,849 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroSixFourAlexanderStreetMember |  |  |
Total | 3,718 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroSixFourAlexanderStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 825 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroSixFourAlexanderStreetMember |  |  |
1901 Raymond Ave SW [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Renton, WA |  |  |
Encumbrances | 1,101 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroOneRaymondAvenueSwMember |  |  |
Initial Cost of Land | 4,458 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroOneRaymondAvenueSwMember |  |  |
Building and Improvements | 2,659 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroOneRaymondAvenueSwMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 400 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroOneRaymondAvenueSwMember |  |  |
Land | 4,594 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroOneRaymondAvenueSwMember |  |  |
Building and improvements | 2,923 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroOneRaymondAvenueSwMember |  |  |
Total | 7,517 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroOneRaymondAvenueSwMember |  |  |
Accumulated depreciation 12/31/2012 | 624 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroOneRaymondAvenueSwMember |  |  |
19014 64th Avenue South [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Kent, WA |  |  |
Encumbrances | 3,063 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroOneFourSixFourAvenueSouthMember |  |  |
Initial Cost of Land | 1,990 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroOneFourSixFourAvenueSouthMember |  |  |
Building and Improvements | 3,979 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroOneFourSixFourAvenueSouthMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 514 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroOneFourSixFourAvenueSouthMember |  |  |
Land | 2,042 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroOneFourSixFourAvenueSouthMember |  |  |
Building and improvements | 4,441 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroOneFourSixFourAvenueSouthMember |  |  |
Total | 6,483 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroOneFourSixFourAvenueSouthMember |  |  |
Accumulated depreciation 12/31/2012 | 1,116 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroOneFourSixFourAvenueSouthMember |  |  |
18640 68th Avenue South [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Kent, WA |  |  |
Encumbrances | 440 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightSixFourZeroSixEightAvenueSouthMember |  |  |
Initial Cost of Land | 1,218 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightSixFourZeroSixEightAvenueSouthMember |  |  |
Building and Improvements | 1,950 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightSixFourZeroSixEightAvenueSouthMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 307 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightSixFourZeroSixEightAvenueSouthMember |  |  |
Land | 1,258 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightSixFourZeroSixEightAvenueSouthMember |  |  |
Building and improvements | 2,217 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightSixFourZeroSixEightAvenueSouthMember |  |  |
Total | 3,475 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightSixFourZeroSixEightAvenueSouthMember |  |  |
Accumulated depreciation 12/31/2012 | 551 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightSixFourZeroSixEightAvenueSouthMember |  |  |
1944 Vista Bella Way [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Rancho Dominguez, CA |  |  |
Encumbrances | 3,620 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineFourFourVistaBellaWayMember |  |  |
Initial Cost of Land | 1,746 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineFourFourVistaBellaWayMember |  |  |
Building and Improvements | 3,148 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineFourFourVistaBellaWayMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 465 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineFourFourVistaBellaWayMember |  |  |
Land | 1,822 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineFourFourVistaBellaWayMember |  |  |
Building and improvements | 3,537 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineFourFourVistaBellaWayMember |  |  |
Total | 5,359 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineFourFourVistaBellaWayMember |  |  |
Accumulated depreciation 12/31/2012 | 1,298 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineFourFourVistaBellaWayMember |  |  |
2000 Vista Bella Way [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Rancho Dominguez, CA |  |  |
Encumbrances | 1,314 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroZeroVistaBellaWayMember |  |  |
Initial Cost of Land | 817 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroZeroVistaBellaWayMember |  |  |
Building and Improvements | 1,673 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroZeroVistaBellaWayMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 292 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroZeroVistaBellaWayMember |  |  |
Land | 853 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroZeroVistaBellaWayMember |  |  |
Building and improvements | 1,929 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroZeroVistaBellaWayMember |  |  |
Total | 2,782 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroZeroVistaBellaWayMember |  |  |
Accumulated depreciation 12/31/2012 | 737 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroZeroZeroVistaBellaWayMember |  |  |
2835 East Ana Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Rancho Dominguez, CA |  |  |
Encumbrances | 3,105 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightThreeFiveEastAnaStreetMember |  |  |
Initial Cost of Land | 1,682 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightThreeFiveEastAnaStreetMember |  |  |
Building and Improvements | 2,750 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightThreeFiveEastAnaStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 339 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightThreeFiveEastAnaStreetMember |  |  |
Land | 1,772 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightThreeFiveEastAnaStreetMember |  |  |
Building and improvements | 2,999 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightThreeFiveEastAnaStreetMember |  |  |
Total | 4,771 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightThreeFiveEastAnaStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 963 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoEightThreeFiveEastAnaStreetMember |  |  |
16275 Technology Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | San Diego, CA |  |  |
Initial Cost of Land | 2,848 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixTwoSevenFiveTechnologyDriveMember |  |  |
Building and Improvements | 8,641 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixTwoSevenFiveTechnologyDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 527 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixTwoSevenFiveTechnologyDriveMember |  |  |
Land | 2,859 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixTwoSevenFiveTechnologyDriveMember |  |  |
Building and improvements | 9,157 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixTwoSevenFiveTechnologyDriveMember |  |  |
Total | 12,016 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixTwoSevenFiveTechnologyDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 2,359 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneSixTwoSevenFiveTechnologyDriveMember |  |  |
8921- 8971 Fost Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Hazelwood, MO |  |  |
Initial Cost of Land | 431 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightNineTwoOneToEightNineSevenOneFostAvenueMember |  |  |
Building and Improvements | 2,479 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightNineTwoOneToEightNineSevenOneFostAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 818 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightNineTwoOneToEightNineSevenOneFostAvenueMember |  |  |
Land | 431 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightNineTwoOneToEightNineSevenOneFostAvenueMember |  |  |
Building and improvements | 3,297 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightNineTwoOneToEightNineSevenOneFostAvenueMember |  |  |
Total | 3,728 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightNineTwoOneToEightNineSevenOneFostAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 1,456 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightNineTwoOneToEightNineSevenOneFostAvenueMember |  |  |
9043-9083 Frost Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Hazelwood, MO |  |  |
Initial Cost of Land | 319 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineZeroFourThreeToNineZeroEightThreeFrostAvenueMember |  |  |
Building and Improvements | 1,838 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineZeroFourThreeToNineZeroEightThreeFrostAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 2,338 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineZeroFourThreeToNineZeroEightThreeFrostAvenueMember |  |  |
Land | 319 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineZeroFourThreeToNineZeroEightThreeFrostAvenueMember |  |  |
Building and improvements | 4,176 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineZeroFourThreeToNineZeroEightThreeFrostAvenueMember |  |  |
Total | 4,495 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineZeroFourThreeToNineZeroEightThreeFrostAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 1,480 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineZeroFourThreeToNineZeroEightThreeFrostAvenueMember |  |  |
10431 Midwest Industrial Blvd [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Olivette, MO |  |  |
Encumbrances | 1,446 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroFourThreeOneToOneZeroFourFourNineMidwestIndustrialBlvdMember |  |  |
Initial Cost of Land | 237 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroFourThreeOneToOneZeroFourFourNineMidwestIndustrialBlvdMember |  |  |
Building and Improvements | 1,360 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroFourThreeOneToOneZeroFourFourNineMidwestIndustrialBlvdMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 745 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroFourThreeOneToOneZeroFourFourNineMidwestIndustrialBlvdMember |  |  |
Land | 237 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroFourThreeOneToOneZeroFourFourNineMidwestIndustrialBlvdMember |  |  |
Building and improvements | 2,105 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroFourThreeOneToOneZeroFourFourNineMidwestIndustrialBlvdMember |  |  |
Total | 2,342 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroFourThreeOneToOneZeroFourFourNineMidwestIndustrialBlvdMember |  |  |
Accumulated depreciation 12/31/2012 | 875 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroFourThreeOneToOneZeroFourFourNineMidwestIndustrialBlvdMember |  |  |
10751 Midwest Industrial Boulevard [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Olivette, MO |  |  |
Initial Cost of Land | 193 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroSevenFiveOneMidwestIndustrialBoulevardMember |  |  |
Building and Improvements | 1,119 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroSevenFiveOneMidwestIndustrialBoulevardMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 294 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroSevenFiveOneMidwestIndustrialBoulevardMember |  |  |
Land | 194 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroSevenFiveOneMidwestIndustrialBoulevardMember |  |  |
Building and improvements | 1,412 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroSevenFiveOneMidwestIndustrialBoulevardMember |  |  |
Total | 1,606 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroSevenFiveOneMidwestIndustrialBoulevardMember |  |  |
Accumulated depreciation 12/31/2012 | 584 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroSevenFiveOneMidwestIndustrialBoulevardMember |  |  |
6951 N Hanley [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Hazelwood, MO |  |  |
Initial Cost of Land | 405 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixNineFiveOneNHanleyDMember |  |  |
Building and Improvements | 2,295 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixNineFiveOneNHanleyDMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 2,577 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixNineFiveOneNHanleyDMember |  |  |
Land | 419 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixNineFiveOneNHanleyDMember |  |  |
Building and improvements | 4,858 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixNineFiveOneNHanleyDMember |  |  |
Total | 5,277 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixNineFiveOneNHanleyDMember |  |  |
Accumulated depreciation 12/31/2012 | 1,839 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixNineFiveOneNHanleyDMember |  |  |
1067-1083 Warson-Bldg A [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | St. Louis, MO |  |  |
Encumbrances | 1,642 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroSixSevenToOneZeroEightThreeWarsonBuildingMember |  |  |
Initial Cost of Land | 246 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroSixSevenToOneZeroEightThreeWarsonBuildingMember |  |  |
Building and Improvements | 1,359 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroSixSevenToOneZeroEightThreeWarsonBuildingMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 826 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroSixSevenToOneZeroEightThreeWarsonBuildingMember |  |  |
Land | 251 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroSixSevenToOneZeroEightThreeWarsonBuildingMember |  |  |
Building and improvements | 2,180 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroSixSevenToOneZeroEightThreeWarsonBuildingMember |  |  |
Total | 2,431 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroSixSevenToOneZeroEightThreeWarsonBuildingMember |  |  |
Accumulated depreciation 12/31/2012 | 570 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroSixSevenToOneZeroEightThreeWarsonBuildingMember |  |  |
1093-1107 Warson-Bldg B [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | St. Louis, MO |  |  |
Encumbrances | 2,813 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroNineThreeToOneOneZeroSevenWarsonBuildingMember |  |  |
Initial Cost of Land | 380 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroNineThreeToOneOneZeroSevenWarsonBuildingMember |  |  |
Building and Improvements | 2,103 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroNineThreeToOneOneZeroSevenWarsonBuildingMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,681 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroNineThreeToOneOneZeroSevenWarsonBuildingMember |  |  |
Land | 388 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroNineThreeToOneOneZeroSevenWarsonBuildingMember |  |  |
Building and improvements | 3,776 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroNineThreeToOneOneZeroSevenWarsonBuildingMember |  |  |
Total | 4,164 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroNineThreeToOneOneZeroSevenWarsonBuildingMember |  |  |
Accumulated depreciation 12/31/2012 | 1,027 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroNineThreeToOneOneZeroSevenWarsonBuildingMember |  |  |
1113-1129 Warson-Bldg C [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | St. Louis, MO |  |  |
Encumbrances | 2,322 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneOneThreeToOneOneTwoNineWarsonBuildingMember |  |  |
Initial Cost of Land | 303 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneOneThreeToOneOneTwoNineWarsonBuildingMember |  |  |
Building and Improvements | 1,680 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneOneThreeToOneOneTwoNineWarsonBuildingMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,454 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneOneThreeToOneOneTwoNineWarsonBuildingMember |  |  |
Land | 310 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneOneThreeToOneOneTwoNineWarsonBuildingMember |  |  |
Building and improvements | 3,127 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneOneThreeToOneOneTwoNineWarsonBuildingMember |  |  |
Total | 3,437 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneOneThreeToOneOneTwoNineWarsonBuildingMember |  |  |
Accumulated depreciation 12/31/2012 | 1,139 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneOneThreeToOneOneTwoNineWarsonBuildingMember |  |  |
1131-1151 Warson-Bldg D [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | St. Louis, MO |  |  |
Encumbrances | 2,198 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneThreeOneToOneOneFiveOneWarsonBuildingMember |  |  |
Initial Cost of Land | 353 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneThreeOneToOneOneFiveOneWarsonBuildingMember |  |  |
Building and Improvements | 1,952 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneThreeOneToOneOneFiveOneWarsonBuildingMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 949 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneThreeOneToOneOneFiveOneWarsonBuildingMember |  |  |
Land | 360 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneThreeOneToOneOneFiveOneWarsonBuildingMember |  |  |
Building and improvements | 2,894 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneThreeOneToOneOneFiveOneWarsonBuildingMember |  |  |
Total | 3,254 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneThreeOneToOneOneFiveOneWarsonBuildingMember |  |  |
Accumulated depreciation 12/31/2012 | 766 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneThreeOneToOneOneFiveOneWarsonBuildingMember |  |  |
6821-6857 Hazelwood Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Berkeley, MO |  |  |
Initial Cost of Land | 985 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixEightTwoOneToSixEightFiveSevenHazelwoodAvenueMember |  |  |
Building and Improvements | 6,205 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixEightTwoOneToSixEightFiveSevenHazelwoodAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 908 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixEightTwoOneToSixEightFiveSevenHazelwoodAvenueMember |  |  |
Land | 985 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixEightTwoOneToSixEightFiveSevenHazelwoodAvenueMember |  |  |
Building and improvements | 7,113 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixEightTwoOneToSixEightFiveSevenHazelwoodAvenueMember |  |  |
Total | 8,098 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixEightTwoOneToSixEightFiveSevenHazelwoodAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 2,090 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixEightTwoOneToSixEightFiveSevenHazelwoodAvenueMember |  |  |
13701 Rider Trail North [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Earth City, MO |  |  |
Initial Cost of Land | 800 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeSevenZeroOneRiderTrailNorthMember |  |  |
Building and Improvements | 2,099 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeSevenZeroOneRiderTrailNorthMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 710 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeSevenZeroOneRiderTrailNorthMember |  |  |
Land | 804 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeSevenZeroOneRiderTrailNorthMember |  |  |
Building and improvements | 2,805 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeSevenZeroOneRiderTrailNorthMember |  |  |
Total | 3,609 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeSevenZeroOneRiderTrailNorthMember |  |  |
Accumulated depreciation 12/31/2012 | 1,025 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeSevenZeroOneRiderTrailNorthMember |  |  |
1908-2000 Innerbelt [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Overland, MO |  |  |
Encumbrances | 7,215 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroEightToTwoZeroZeroZeroInnerbeltDMember |  |  |
Initial Cost of Land | 1,590 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroEightToTwoZeroZeroZeroInnerbeltDMember |  |  |
Building and Improvements | 9,026 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroEightToTwoZeroZeroZeroInnerbeltDMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,095 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroEightToTwoZeroZeroZeroInnerbeltDMember |  |  |
Land | 1,591 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroEightToTwoZeroZeroZeroInnerbeltDMember |  |  |
Building and improvements | 10,120 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroEightToTwoZeroZeroZeroInnerbeltDMember |  |  |
Total | 11,711 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroEightToTwoZeroZeroZeroInnerbeltDMember |  |  |
Accumulated depreciation 12/31/2012 | 3,741 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroEightToTwoZeroZeroZeroInnerbeltDMember |  |  |
9060 Latty Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Berkeley, MO |  |  |
Initial Cost of Land | 687 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineZeroSixZeroLattyAvenueMember |  |  |
Building and Improvements | 1,947 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineZeroSixZeroLattyAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (90)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineZeroSixZeroLattyAvenueMember |  |  |
Land | 694 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineZeroSixZeroLattyAvenueMember |  |  |
Building and improvements | 1,850 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineZeroSixZeroLattyAvenueMember |  |  |
Total | 2,544 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineZeroSixZeroLattyAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 1,554 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineZeroSixZeroLattyAvenueMember |  |  |
21-25 Gateway Commerce Center [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Edwardsville, IL |  |  |
Initial Cost of Land | 1,874 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneToTwoFiveGatewayCommerceCenterMember |  |  |
Building and Improvements | 31,958 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneToTwoFiveGatewayCommerceCenterMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (331)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneToTwoFiveGatewayCommerceCenterMember |  |  |
Land | 1,902 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneToTwoFiveGatewayCommerceCenterMember |  |  |
Building and improvements | 31,599 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneToTwoFiveGatewayCommerceCenterMember |  |  |
Total | 33,501 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneToTwoFiveGatewayCommerceCenterMember |  |  |
Accumulated depreciation 12/31/2012 | 7,272 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneToTwoFiveGatewayCommerceCenterMember |  |  |
6647 Romiss Court [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | St. Louis, MO |  |  |
Initial Cost of Land | 230 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSixFourSevenRomissCourtMember |  |  |
Building and Improvements | 681 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSixFourSevenRomissCourtMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (8)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSixFourSevenRomissCourtMember |  |  |
Land | 241 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSixFourSevenRomissCourtMember |  |  |
Building and improvements | 662 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSixFourSevenRomissCourtMember |  |  |
Total | 903 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSixFourSevenRomissCourtMember |  |  |
Accumulated depreciation 12/31/2012 | 245 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSixFourSevenRomissCourtMember |  |  |
5313 Johns Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Tampa, FL |  |  |
Initial Cost of Land | 204 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThreeOneThreeJohnsRoadMember |  |  |
Building and Improvements | 1,159 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThreeOneThreeJohnsRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 573 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThreeOneThreeJohnsRoadMember |  |  |
Land | 257 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThreeOneThreeJohnsRoadMember |  |  |
Building and improvements | 1,679 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThreeOneThreeJohnsRoadMember |  |  |
Total | 1,936 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThreeOneThreeJohnsRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 640 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveThreeOneThreeJohnsRoadMember |  |  |
5525 Johns Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Tampa, FL |  |  |
Initial Cost of Land | 192 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveTwoFiveJohnsRoadMember |  |  |
Building and Improvements | 1,086 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveTwoFiveJohnsRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 294 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveTwoFiveJohnsRoadMember |  |  |
Land | 200 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveTwoFiveJohnsRoadMember |  |  |
Building and improvements | 1,372 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveTwoFiveJohnsRoadMember |  |  |
Total | 1,572 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveTwoFiveJohnsRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 539 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveTwoFiveJohnsRoadMember |  |  |
5709 Johns Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Tampa, FL |  |  |
Initial Cost of Land | 192 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveSevenZeroNineJohnsRoadMember |  |  |
Building and Improvements | 1,086 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveSevenZeroNineJohnsRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 197 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveSevenZeroNineJohnsRoadMember |  |  |
Land | 200 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveSevenZeroNineJohnsRoadMember |  |  |
Building and improvements | 1,275 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveSevenZeroNineJohnsRoadMember |  |  |
Total | 1,475 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveSevenZeroNineJohnsRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 534 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveSevenZeroNineJohnsRoadMember |  |  |
5711 Johns Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Tampa, FL |  |  |
Initial Cost of Land | 243 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveSevenOneOneJohnsRoadMember |  |  |
Building and Improvements | 1,376 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveSevenOneOneJohnsRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 159 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveSevenOneOneJohnsRoadMember |  |  |
Land | 255 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveSevenOneOneJohnsRoadMember |  |  |
Building and improvements | 1,523 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveSevenOneOneJohnsRoadMember |  |  |
Total | 1,778 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveSevenOneOneJohnsRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 640 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveSevenOneOneJohnsRoadMember |  |  |
5453 W Waters Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Tampa, FL |  |  |
Initial Cost of Land | 71 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourFiveThreeWWatersAvenueMember |  |  |
Building and Improvements | 402 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourFiveThreeWWatersAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 163 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourFiveThreeWWatersAvenueMember |  |  |
Land | 82 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourFiveThreeWWatersAvenueMember |  |  |
Building and improvements | 554 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourFiveThreeWWatersAvenueMember |  |  |
Total | 636 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourFiveThreeWWatersAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 236 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourFiveThreeWWatersAvenueMember |  |  |
5455 W Waters Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Tampa, FL |  |  |
Initial Cost of Land | 307 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourFiveFiveWWatersAvenueMember |  |  |
Building and Improvements | 1,742 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourFiveFiveWWatersAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 747 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourFiveFiveWWatersAvenueMember |  |  |
Land | 326 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourFiveFiveWWatersAvenueMember |  |  |
Building and improvements | 2,470 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourFiveFiveWWatersAvenueMember |  |  |
Total | 2,796 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourFiveFiveWWatersAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 1,043 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourFiveFiveWWatersAvenueMember |  |  |
5553 W Waters Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Tampa, FL |  |  |
Initial Cost of Land | 307 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveFiveThreeWWatersAvenueMember |  |  |
Building and Improvements | 1,742 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveFiveThreeWWatersAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 417 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveFiveThreeWWatersAvenueMember |  |  |
Land | 326 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveFiveThreeWWatersAvenueMember |  |  |
Building and improvements | 2,140 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveFiveThreeWWatersAvenueMember |  |  |
Total | 2,466 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveFiveThreeWWatersAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 885 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveFiveThreeWWatersAvenueMember |  |  |
5501 W Waters Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Tampa, FL |  |  |
Initial Cost of Land | 215 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveZeroOneWWatersAvenueMember |  |  |
Building and Improvements | 871 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveZeroOneWWatersAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 298 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveZeroOneWWatersAvenueMember |  |  |
Land | 242 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveZeroOneWWatersAvenueMember |  |  |
Building and improvements | 1,142 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveZeroOneWWatersAvenueMember |  |  |
Total | 1,384 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveZeroOneWWatersAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 491 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveZeroOneWWatersAvenueMember |  |  |
5503 W Waters Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Tampa, FL |  |  |
Initial Cost of Land | 98 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveZeroThreeWWatersAvenueMember |  |  |
Building and Improvements | 402 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveZeroThreeWWatersAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 328 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveZeroThreeWWatersAvenueMember |  |  |
Land | 110 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveZeroThreeWWatersAvenueMember |  |  |
Building and improvements | 718 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveZeroThreeWWatersAvenueMember |  |  |
Total | 828 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveZeroThreeWWatersAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 374 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveZeroThreeWWatersAvenueMember |  |  |
5555 W Waters Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Tampa, FL |  |  |
Initial Cost of Land | 213 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveFiveFiveWWatersAvenueMember |  |  |
Building and Improvements | 1,206 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveFiveFiveWWatersAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 230 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveFiveFiveWWatersAvenueMember |  |  |
Land | 221 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveFiveFiveWWatersAvenueMember |  |  |
Building and improvements | 1,428 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveFiveFiveWWatersAvenueMember |  |  |
Total | 1,649 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveFiveFiveWWatersAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 625 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveFiveFiveWWatersAvenueMember |  |  |
5557 W Waters Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Tampa, FL |  |  |
Initial Cost of Land | 59 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveFiveSevenWWatersAvenueMember |  |  |
Building and Improvements | 335 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveFiveSevenWWatersAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 59 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveFiveSevenWWatersAvenueMember |  |  |
Land | 62 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveFiveSevenWWatersAvenueMember |  |  |
Building and improvements | 391 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveFiveSevenWWatersAvenueMember |  |  |
Total | 453 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveFiveSevenWWatersAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 160 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveFiveSevenWWatersAvenueMember |  |  |
5463 W Waters Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Tampa, FL |  |  |
Initial Cost of Land | 497 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourSixThreeWWatersAvenueMember |  |  |
Building and Improvements | 2,751 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourSixThreeWWatersAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 694 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourSixThreeWWatersAvenueMember |  |  |
Land | 560 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourSixThreeWWatersAvenueMember |  |  |
Building and improvements | 3,382 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourSixThreeWWatersAvenueMember |  |  |
Total | 3,942 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourSixThreeWWatersAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 1,371 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourSixThreeWWatersAvenueMember |  |  |
5461 W Waters Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Tampa, FL |  |  |
Initial Cost of Land | 261 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourSixOneWWatersMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,355 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourSixOneWWatersMember |  |  |
Land | 265 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourSixOneWWatersMember |  |  |
Building and improvements | 1,351 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourSixOneWWatersMember |  |  |
Total | 1,616 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourSixOneWWatersMember |  |  |
Accumulated depreciation 12/31/2012 | 541 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourSixOneWWatersMember |  |  |
5481 W Waters Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Tampa, FL |  |  |
Initial Cost of Land | 558 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourEightOneWWatersAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 2,263 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourEightOneWWatersAvenueMember |  |  |
Land | 561 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourEightOneWWatersAvenueMember |  |  |
Building and improvements | 2,260 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourEightOneWWatersAvenueMember |  |  |
Total | 2,821 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourEightOneWWatersAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 832 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFourEightOneWWatersAvenueMember |  |  |
4515-4519 George Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Tampa, FL |  |  |
Initial Cost of Land | 633 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveOneFiveToFourFiveOneNineGeorgeRoadMember |  |  |
Building and Improvements | 3,587 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveOneFiveToFourFiveOneNineGeorgeRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 854 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveOneFiveToFourFiveOneNineGeorgeRoadMember |  |  |
Land | 640 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveOneFiveToFourFiveOneNineGeorgeRoadMember |  |  |
Building and improvements | 4,434 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveOneFiveToFourFiveOneNineGeorgeRoadMember |  |  |
Total | 5,074 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveOneFiveToFourFiveOneNineGeorgeRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 1,526 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourFiveOneFiveToFourFiveOneNineGeorgeRoadMember |  |  |
6089 Johns Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Tampa, FL |  |  |
Initial Cost of Land | 180 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixZeroEightNineJohnsRoadMember |  |  |
Building and Improvements | 987 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixZeroEightNineJohnsRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 2 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixZeroEightNineJohnsRoadMember |  |  |
Land | 186 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixZeroEightNineJohnsRoadMember |  |  |
Building and improvements | 983 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixZeroEightNineJohnsRoadMember |  |  |
Total | 1,169 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixZeroEightNineJohnsRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 320 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixZeroEightNineJohnsRoadMember |  |  |
6091 Johns Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Tampa, FL |  |  |
Initial Cost of Land | 140 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixZeroNineOneJohnsRoadMember |  |  |
Building and Improvements | 730 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixZeroNineOneJohnsRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (32)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixZeroNineOneJohnsRoadMember |  |  |
Land | 144 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixZeroNineOneJohnsRoadMember |  |  |
Building and improvements | 694 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixZeroNineOneJohnsRoadMember |  |  |
Total | 838 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixZeroNineOneJohnsRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 219 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixZeroNineOneJohnsRoadMember |  |  |
6103 Johns Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Tampa, FL |  |  |
Initial Cost of Land | 220 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixOneZeroThreeJohnsRoadMember |  |  |
Building and Improvements | 1,160 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixOneZeroThreeJohnsRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 16 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixOneZeroThreeJohnsRoadMember |  |  |
Land | 226 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixOneZeroThreeJohnsRoadMember |  |  |
Building and improvements | 1,170 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixOneZeroThreeJohnsRoadMember |  |  |
Total | 1,396 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixOneZeroThreeJohnsRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 387 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixOneZeroThreeJohnsRoadMember |  |  |
6201 Johns Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Tampa, FL |  |  |
Initial Cost of Land | 200 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixTwoZeroOneJohnsRoadMember |  |  |
Building and Improvements | 1,107 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixTwoZeroOneJohnsRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 3 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixTwoZeroOneJohnsRoadMember |  |  |
Land | 205 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixTwoZeroOneJohnsRoadMember |  |  |
Building and improvements | 1,105 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixTwoZeroOneJohnsRoadMember |  |  |
Total | 1,310 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixTwoZeroOneJohnsRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 415 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixTwoZeroOneJohnsRoadMember |  |  |
6203 Johns Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Tampa, FL |  |  |
Initial Cost of Land | 300 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixTwoZeroThreeJohnsRoadMember |  |  |
Building and Improvements | 1,460 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixTwoZeroThreeJohnsRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (311)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixTwoZeroThreeJohnsRoadMember |  |  |
Land | 311 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixTwoZeroThreeJohnsRoadMember |  |  |
Building and improvements | 1,138 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixTwoZeroThreeJohnsRoadMember |  |  |
Total | 1,449 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixTwoZeroThreeJohnsRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 348 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixTwoZeroThreeJohnsRoadMember |  |  |
6205 Johns Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Tampa, FL |  |  |
Initial Cost of Land | 270 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixTwoZeroFiveJohnsRoadMember |  |  |
Building and Improvements | 1,363 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixTwoZeroFiveJohnsRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 152 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixTwoZeroFiveJohnsRoadMember |  |  |
Land | 278 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixTwoZeroFiveJohnsRoadMember |  |  |
Building and improvements | 1,507 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixTwoZeroFiveJohnsRoadMember |  |  |
Total | 1,785 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixTwoZeroFiveJohnsRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 445 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixTwoZeroFiveJohnsRoadMember |  |  |
6101 Johns Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Tampa, FL |  |  |
Initial Cost of Land | 210 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixOneZeroOneJohnsRoadMember |  |  |
Building and Improvements | 833 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixOneZeroOneJohnsRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 49 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixOneZeroOneJohnsRoadMember |  |  |
Land | 216 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixOneZeroOneJohnsRoadMember |  |  |
Building and improvements | 876 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixOneZeroOneJohnsRoadMember |  |  |
Total | 1,092 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixOneZeroOneJohnsRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 304 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixOneZeroOneJohnsRoadMember |  |  |
4908 Tampa West Blvd [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Tampa, FL |  |  |
Initial Cost of Land | 2,622 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourNineZeroEightTampaWestBlvdMember |  |  |
Building and Improvements | 8,643 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourNineZeroEightTampaWestBlvdMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (820)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourNineZeroEightTampaWestBlvdMember |  |  |
Land | 2,635 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourNineZeroEightTampaWestBlvdMember |  |  |
Building and improvements | 7,810 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourNineZeroEightTampaWestBlvdMember |  |  |
Total | 10,445 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourNineZeroEightTampaWestBlvdMember |  |  |
Accumulated depreciation 12/31/2012 | 2,722 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourNineZeroEightTampaWestBlvdMember |  |  |
7201-7281 Bryan Dairy Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Largo, FL |  |  |
Initial Cost of Land | 1,895 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenTwoZeroOneToSevenTwoFourFiveBryanDairyRoadDMember |  |  |
Building and Improvements | 5,408 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenTwoZeroOneToSevenTwoFourFiveBryanDairyRoadDMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (1,552)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenTwoZeroOneToSevenTwoFourFiveBryanDairyRoadDMember |  |  |
Land | 1,365 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenTwoZeroOneToSevenTwoFourFiveBryanDairyRoadDMember |  |  |
Building and improvements | 4,386 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenTwoZeroOneToSevenTwoFourFiveBryanDairyRoadDMember |  |  |
Total | 5,751 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenTwoZeroOneToSevenTwoFourFiveBryanDairyRoadDMember |  |  |
Accumulated depreciation 12/31/2012 | 1,129 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenTwoZeroOneToSevenTwoFourFiveBryanDairyRoadDMember |  |  |
4900- 4914 Creekside Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Clearwater, FL |  |  |
Initial Cost of Land | 3,702 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourNineZeroZeroToFourNineOneFourCreeksideDriveHMember |  |  |
Building and Improvements | 7,338 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourNineZeroZeroToFourNineOneFourCreeksideDriveHMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (3,486)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourNineZeroZeroToFourNineOneFourCreeksideDriveHMember |  |  |
Land | 2,245 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourNineZeroZeroToFourNineOneFourCreeksideDriveHMember |  |  |
Building and improvements | 5,309 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourNineZeroZeroToFourNineOneFourCreeksideDriveHMember |  |  |
Total | 7,554 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourNineZeroZeroToFourNineOneFourCreeksideDriveHMember |  |  |
Accumulated depreciation 12/31/2012 | 1,787 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourNineZeroZeroToFourNineOneFourCreeksideDriveHMember |  |  |
12345 Starkey Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Largo, FL |  |  |
Initial Cost of Land | 898 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoThreeFourFiveStarkeyRoadMember |  |  |
Building and Improvements | 2,078 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoThreeFourFiveStarkeyRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (629)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoThreeFourFiveStarkeyRoadMember |  |  |
Land | 599 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoThreeFourFiveStarkeyRoadMember |  |  |
Building and improvements | 1,748 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoThreeFourFiveStarkeyRoadMember |  |  |
Total | 2,347 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoThreeFourFiveStarkeyRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 651 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoThreeFourFiveStarkeyRoadMember |  |  |
5050 Kendrick Court [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Grand Rapids, MI |  |  |
Initial Cost of Land | 1,721 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroFiveZeroKendrickCourtMember |  |  |
Building and Improvements | 11,433 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroFiveZeroKendrickCourtMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (2,272)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroFiveZeroKendrickCourtMember |  |  |
Land | 988 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroFiveZeroKendrickCourtMember |  |  |
Building and improvements | 9,894 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroFiveZeroKendrickCourtMember |  |  |
Total | 10,882 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroFiveZeroKendrickCourtMember |  |  |
Accumulated depreciation 12/31/2012 | 7,264 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveZeroFiveZeroKendrickCourtMember |  |  |
2250 Delaware Ave [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Des Moines, IA |  |  |
Initial Cost of Land | 277 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoTwoFiveZeroDelawareAvenueMember |  |  |
Building and Improvements | 1,609 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoTwoFiveZeroDelawareAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (133)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoTwoFiveZeroDelawareAvenueMember |  |  |
Land | 173 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoTwoFiveZeroDelawareAvenueMember |  |  |
Building and improvements | 1,580 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoTwoFiveZeroDelawareAvenueMember |  |  |
Total | 1,753 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoTwoFiveZeroDelawareAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 743 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoTwoFiveZeroDelawareAvenueMember |  |  |
9601A Dessau Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Austin, TX |  |  |
Encumbrances | 1,187 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSixZeroOneDessauRoadMember |  |  |
Initial Cost of Land | 255 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSixZeroOneDessauRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,893 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSixZeroOneDessauRoadMember |  |  |
Land | 366 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSixZeroOneDessauRoadMember |  |  |
Building and improvements | 1,782 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSixZeroOneDessauRoadMember |  |  |
Total | 2,148 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSixZeroOneDessauRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 711 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSixZeroOneDessauRoadMember |  |  |
9601C Dessau Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Austin, TX |  |  |
Encumbrances | 1,418 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSixZeroOneCDessauRoadMember |  |  |
Initial Cost of Land | 248 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSixZeroOneCDessauRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 2,319 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSixZeroOneCDessauRoadMember |  |  |
Land | 355 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSixZeroOneCDessauRoadMember |  |  |
Building and improvements | 2,212 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSixZeroOneCDessauRoadMember |  |  |
Total | 2,567 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSixZeroOneCDessauRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 1,089 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSixZeroOneCDessauRoadMember |  |  |
9601B Dessau Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Austin, TX |  |  |
Encumbrances | 1,177 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSixZeroOneBDessauRoadMember |  |  |
Initial Cost of Land | 248 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSixZeroOneBDessauRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,883 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSixZeroOneBDessauRoadMember |  |  |
Land | 355 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSixZeroOneBDessauRoadMember |  |  |
Building and improvements | 1,776 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSixZeroOneBDessauRoadMember |  |  |
Total | 2,131 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSixZeroOneBDessauRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 652 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_NineSixZeroOneBDessauRoadMember |  |  |
6266 Hurt Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Horn Lake, MS |  |  |
Initial Cost of Land | 427 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixTwoSixSixHurtRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 3,712 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixTwoSixSixHurtRoadMember |  |  |
Land | 387 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixTwoSixSixHurtRoadMember |  |  |
Building and improvements | 3,752 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixTwoSixSixHurtRoadMember |  |  |
Total | 4,139 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixTwoSixSixHurtRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 836 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixTwoSixSixHurtRoadMember |  |  |
665 N. Baldwin Park Blvd [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | City of Industry, CA |  |  |
Encumbrances | 4,226 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSixFiveNBaldwinParkBlvdMember |  |  |
Initial Cost of Land | 2,124 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSixFiveNBaldwinParkBlvdMember |  |  |
Building and Improvements | 5,219 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSixFiveNBaldwinParkBlvdMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,601 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSixFiveNBaldwinParkBlvdMember |  |  |
Land | 2,143 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSixFiveNBaldwinParkBlvdMember |  |  |
Building and improvements | 6,801 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSixFiveNBaldwinParkBlvdMember |  |  |
Total | 8,944 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSixFiveNBaldwinParkBlvdMember |  |  |
Accumulated depreciation 12/31/2012 | 2,477 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixSixFiveNBaldwinParkBlvdMember |  |  |
27801 Avenue Scott [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Santa Clarita, CA |  |  |
Encumbrances | 7,228 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSevenEightZeroOneAvenueScottMember |  |  |
Initial Cost of Land | 2,890 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSevenEightZeroOneAvenueScottMember |  |  |
Building and Improvements | 7,020 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSevenEightZeroOneAvenueScottMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 788 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSevenEightZeroOneAvenueScottMember |  |  |
Land | 2,902 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSevenEightZeroOneAvenueScottMember |  |  |
Building and improvements | 7,796 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSevenEightZeroOneAvenueScottMember |  |  |
Total | 10,698 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSevenEightZeroOneAvenueScottMember |  |  |
Accumulated depreciation 12/31/2012 | 2,377 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSevenEightZeroOneAvenueScottMember |  |  |
2610 & 2660 Columbia [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Torrance, CA |  |  |
Encumbrances | 4,524 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSixOneZeroAndTwoSixSixZeroColumbiaMember |  |  |
Initial Cost of Land | 3,008 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSixOneZeroAndTwoSixSixZeroColumbiaMember |  |  |
Building and Improvements | 5,826 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSixOneZeroAndTwoSixSixZeroColumbiaMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 740 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSixOneZeroAndTwoSixSixZeroColumbiaMember |  |  |
Land | 3,031 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSixOneZeroAndTwoSixSixZeroColumbiaMember |  |  |
Building and improvements | 6,543 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSixOneZeroAndTwoSixSixZeroColumbiaMember |  |  |
Total | 9,574 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSixOneZeroAndTwoSixSixZeroColumbiaMember |  |  |
Accumulated depreciation 12/31/2012 | 1,770 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoSixOneZeroAndTwoSixSixZeroColumbiaMember |  |  |
433 Alaska Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Torrance, CA |  |  |
Initial Cost of Land | 681 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThreeThreeAlaskaAvenueMember |  |  |
Building and Improvements | 168 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThreeThreeAlaskaAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (5)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThreeThreeAlaskaAvenueMember |  |  |
Land | 684 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThreeThreeAlaskaAvenueMember |  |  |
Building and improvements | 160 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThreeThreeAlaskaAvenueMember |  |  |
Total | 844 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThreeThreeAlaskaAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 85 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThreeThreeAlaskaAvenueMember |  |  |
4020 S. Compton Ave [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Los Angeles, CA |  |  |
Initial Cost of Land | 3,800 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourZeroTwoZeroSComptonAvenueMember |  |  |
Building and Improvements | 7,330 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourZeroTwoZeroSComptonAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (233)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourZeroTwoZeroSComptonAvenueMember |  |  |
Land | 3,825 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourZeroTwoZeroSComptonAvenueMember |  |  |
Building and improvements | 7,072 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourZeroTwoZeroSComptonAvenueMember |  |  |
Total | 10,897 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourZeroTwoZeroSComptonAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 1,716 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourZeroTwoZeroSComptonAvenueMember |  |  |
6305 El Camino Real [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Carlsbad, CA |  |  |
Initial Cost of Land | 1,590 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixThreeZeroFiveElCaminoRealMember |  |  |
Building and Improvements | 6,360 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixThreeZeroFiveElCaminoRealMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 7,730 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixThreeZeroFiveElCaminoRealMember |  |  |
Land | 1,590 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixThreeZeroFiveElCaminoRealMember |  |  |
Building and improvements | 14,090 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixThreeZeroFiveElCaminoRealMember |  |  |
Total | 15,680 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixThreeZeroFiveElCaminoRealMember |  |  |
Accumulated depreciation 12/31/2012 | 3,419 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixThreeZeroFiveElCaminoRealMember |  |  |
2325 Camino Vida Roble [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Carlsbad, CA |  |  |
Encumbrances | 1,954 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeTwoFiveCaminoVidaRobleMember |  |  |
Initial Cost of Land | 1,441 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeTwoFiveCaminoVidaRobleMember |  |  |
Building and Improvements | 1,239 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeTwoFiveCaminoVidaRobleMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 627 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeTwoFiveCaminoVidaRobleMember |  |  |
Land | 1,446 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeTwoFiveCaminoVidaRobleMember |  |  |
Building and improvements | 1,861 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeTwoFiveCaminoVidaRobleMember |  |  |
Total | 3,307 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeTwoFiveCaminoVidaRobleMember |  |  |
Accumulated depreciation 12/31/2012 | 458 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeTwoFiveCaminoVidaRobleMember |  |  |
2335 Camino Vida Roble [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Carlsbad, CA |  |  |
Encumbrances | 1,055 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeThreeFiveCaminoVidaRobleMember |  |  |
Initial Cost of Land | 817 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeThreeFiveCaminoVidaRobleMember |  |  |
Building and Improvements | 762 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeThreeFiveCaminoVidaRobleMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 207 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeThreeFiveCaminoVidaRobleMember |  |  |
Land | 821 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeThreeFiveCaminoVidaRobleMember |  |  |
Building and improvements | 965 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeThreeFiveCaminoVidaRobleMember |  |  |
Total | 1,786 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeThreeFiveCaminoVidaRobleMember |  |  |
Accumulated depreciation 12/31/2012 | 350 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeThreeFiveCaminoVidaRobleMember |  |  |
2345 Camino Vida Roble [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Carlsbad, CA |  |  |
Encumbrances | 681 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeFourFiveCaminoVidaRobleMember |  |  |
Initial Cost of Land | 562 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeFourFiveCaminoVidaRobleMember |  |  |
Building and Improvements | 456 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeFourFiveCaminoVidaRobleMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 51 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeFourFiveCaminoVidaRobleMember |  |  |
Land | 565 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeFourFiveCaminoVidaRobleMember |  |  |
Building and improvements | 504 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeFourFiveCaminoVidaRobleMember |  |  |
Total | 1,069 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeFourFiveCaminoVidaRobleMember |  |  |
Accumulated depreciation 12/31/2012 | 224 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeFourFiveCaminoVidaRobleMember |  |  |
2355 Camino Vida Roble [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Carlsbad, CA |  |  |
Encumbrances | 640 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeFiveFiveCaminoVidaRobleMember |  |  |
Initial Cost of Land | 481 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeFiveFiveCaminoVidaRobleMember |  |  |
Building and Improvements | 365 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeFiveFiveCaminoVidaRobleMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 237 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeFiveFiveCaminoVidaRobleMember |  |  |
Land | 483 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeFiveFiveCaminoVidaRobleMember |  |  |
Building and improvements | 600 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeFiveFiveCaminoVidaRobleMember |  |  |
Total | 1,083 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeFiveFiveCaminoVidaRobleMember |  |  |
Accumulated depreciation 12/31/2012 | 171 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeFiveFiveCaminoVidaRobleMember |  |  |
2365 Camino Vida Roble [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Carlsbad, CA |  |  |
Encumbrances | 1,212 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeSixFiveCaminoVidaRobleMember |  |  |
Initial Cost of Land | 1,098 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeSixFiveCaminoVidaRobleMember |  |  |
Building and Improvements | 630 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeSixFiveCaminoVidaRobleMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 323 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeSixFiveCaminoVidaRobleMember |  |  |
Land | 1,102 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeSixFiveCaminoVidaRobleMember |  |  |
Building and improvements | 949 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeSixFiveCaminoVidaRobleMember |  |  |
Total | 2,051 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeSixFiveCaminoVidaRobleMember |  |  |
Accumulated depreciation 12/31/2012 | 273 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeSixFiveCaminoVidaRobleMember |  |  |
2375 Camino Vida Roble [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Carlsbad, CA |  |  |
Encumbrances | 1,326 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeSevenFiveCaminoVidaRobleMember |  |  |
Initial Cost of Land | 1,210 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeSevenFiveCaminoVidaRobleMember |  |  |
Building and Improvements | 874 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeSevenFiveCaminoVidaRobleMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 96 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeSevenFiveCaminoVidaRobleMember |  |  |
Land | 1,214 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeSevenFiveCaminoVidaRobleMember |  |  |
Building and improvements | 966 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeSevenFiveCaminoVidaRobleMember |  |  |
Total | 2,180 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeSevenFiveCaminoVidaRobleMember |  |  |
Accumulated depreciation 12/31/2012 | 323 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeSevenFiveCaminoVidaRobleMember |  |  |
6451 El Camino Real [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Carlsbad, CA |  |  |
Initial Cost of Land | 2,885 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFourFiveOneElCaminoRealMember |  |  |
Building and Improvements | 1,931 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFourFiveOneElCaminoRealMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 623 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFourFiveOneElCaminoRealMember |  |  |
Land | 2,895 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFourFiveOneElCaminoRealMember |  |  |
Building and improvements | 2,544 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFourFiveOneElCaminoRealMember |  |  |
Total | 5,439 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFourFiveOneElCaminoRealMember |  |  |
Accumulated depreciation 12/31/2012 | 802 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixFourFiveOneElCaminoRealMember |  |  |
8572 Spectrum Lane [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | San Diego, CA |  |  |
Encumbrances | 2,034 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightFiveSevenTwoSpectrumLaneMember |  |  |
Initial Cost of Land | 806 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightFiveSevenTwoSpectrumLaneMember |  |  |
Building and Improvements | 3,225 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightFiveSevenTwoSpectrumLaneMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 274 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightFiveSevenTwoSpectrumLaneMember |  |  |
Land | 807 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightFiveSevenTwoSpectrumLaneMember |  |  |
Building and improvements | 3,498 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightFiveSevenTwoSpectrumLaneMember |  |  |
Total | 4,305 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightFiveSevenTwoSpectrumLaneMember |  |  |
Accumulated depreciation 12/31/2012 | 680 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightFiveSevenTwoSpectrumLaneMember |  |  |
13100 Gregg Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Poway, CA |  |  |
Initial Cost of Land | 1,040 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeOneZeroZeroGreggStreetMember |  |  |
Building and Improvements | 4,160 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeOneZeroZeroGreggStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 509 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeOneZeroZeroGreggStreetMember |  |  |
Land | 1,073 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeOneZeroZeroGreggStreetMember |  |  |
Building and improvements | 4,636 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeOneZeroZeroGreggStreetMember |  |  |
Total | 5,709 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeOneZeroZeroGreggStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 1,353 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneThreeOneZeroZeroGreggStreetMember |  |  |
21730-21748 Marilla St. [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Chatsworth, CA |  |  |
Encumbrances | 2,766 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneSevenThreeZeroToTwoOneSevenFourEightMarillaStMember |  |  |
Initial Cost of Land | 2,585 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneSevenThreeZeroToTwoOneSevenFourEightMarillaStMember |  |  |
Building and Improvements | 3,210 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneSevenThreeZeroToTwoOneSevenFourEightMarillaStMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 58 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneSevenThreeZeroToTwoOneSevenFourEightMarillaStMember |  |  |
Land | 2,608 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneSevenThreeZeroToTwoOneSevenFourEightMarillaStMember |  |  |
Building and improvements | 3,245 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneSevenThreeZeroToTwoOneSevenFourEightMarillaStMember |  |  |
Total | 5,853 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneSevenThreeZeroToTwoOneSevenFourEightMarillaStMember |  |  |
Accumulated depreciation 12/31/2012 | 912 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoOneSevenThreeZeroToTwoOneSevenFourEightMarillaStMember |  |  |
8015 Paramount [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Pico Rivera, CA |  |  |
Initial Cost of Land | 3,616 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightZeroOneFiveParamountMember |  |  |
Building and Improvements | 3,902 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightZeroOneFiveParamountMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 61 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightZeroOneFiveParamountMember |  |  |
Land | 3,657 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightZeroOneFiveParamountMember |  |  |
Building and improvements | 3,922 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightZeroOneFiveParamountMember |  |  |
Total | 7,579 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightZeroOneFiveParamountMember |  |  |
Accumulated depreciation 12/31/2012 | 1,395 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_EightZeroOneFiveParamountMember |  |  |
3365 E. Slauson [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Vernon, CA |  |  |
Initial Cost of Land | 2,367 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThreeSixFiveESlausonMember |  |  |
Building and Improvements | 3,243 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThreeSixFiveESlausonMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 40 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThreeSixFiveESlausonMember |  |  |
Land | 2,396 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThreeSixFiveESlausonMember |  |  |
Building and improvements | 3,254 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThreeSixFiveESlausonMember |  |  |
Total | 5,650 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThreeSixFiveESlausonMember |  |  |
Accumulated depreciation 12/31/2012 | 1,219 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThreeSixFiveESlausonMember |  |  |
3015 East Ana [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Rancho Dominguez, CA |  |  |
Initial Cost of Land | 19,678 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroOneFiveEastAnaMember |  |  |
Building and Improvements | 9,321 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroOneFiveEastAnaMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 6,305 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroOneFiveEastAnaMember |  |  |
Land | 20,144 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroOneFiveEastAnaMember |  |  |
Building and improvements | 15,160 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroOneFiveEastAnaMember |  |  |
Total | 35,304 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroOneFiveEastAnaMember |  |  |
Accumulated depreciation 12/31/2012 | 3,470 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroOneFiveEastAnaMember |  |  |
19067 Reyes Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Rancho Dominguez, CA |  |  |
Initial Cost of Land | 9,281 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroSixSevenReyesAvenueMember |  |  |
Building and Improvements | 3,920 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroSixSevenReyesAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 102 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroSixSevenReyesAvenueMember |  |  |
Land | 9,381 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroSixSevenReyesAvenueMember |  |  |
Building and improvements | 3,922 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroSixSevenReyesAvenueMember |  |  |
Total | 13,303 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroSixSevenReyesAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 1,557 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroSixSevenReyesAvenueMember |  |  |
24870 Nandina Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Moreno Valley, CA |  |  |
Initial Cost of Land | 13,543 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourEightSevenZeroNandinaAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 20,885 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourEightSevenZeroNandinaAvenueMember |  |  |
Land | 6,482 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourEightSevenZeroNandinaAvenueMember |  |  |
Building and improvements | 27,946 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourEightSevenZeroNandinaAvenueMember |  |  |
Total | 34,428 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourEightSevenZeroNandinaAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 1,627 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoFourEightSevenZeroNandinaAvenueMember |  |  |
1250 Rancho Conejo Blvd [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Thousand Oaks, CA |  |  |
Initial Cost of Land | 1,435 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoFiveZeroRanchoConejoBlvdMember |  |  |
Building and Improvements | 779 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoFiveZeroRanchoConejoBlvdMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 42 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoFiveZeroRanchoConejoBlvdMember |  |  |
Land | 1,441 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoFiveZeroRanchoConejoBlvdMember |  |  |
Building and improvements | 815 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoFiveZeroRanchoConejoBlvdMember |  |  |
Total | 2,256 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoFiveZeroRanchoConejoBlvdMember |  |  |
Accumulated depreciation 12/31/2012 | 331 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoFiveZeroRanchoConejoBlvdMember |  |  |
1260 Rancho Conejo Blvd [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Thousand Oaks, CA |  |  |
Initial Cost of Land | 1,353 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSixZeroRanchoConejoBlvdMember |  |  |
Building and Improvements | 722 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSixZeroRanchoConejoBlvdMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (844)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSixZeroRanchoConejoBlvdMember |  |  |
Land | 675 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSixZeroRanchoConejoBlvdMember |  |  |
Building and improvements | 556 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSixZeroRanchoConejoBlvdMember |  |  |
Total | 1,231 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSixZeroRanchoConejoBlvdMember |  |  |
Accumulated depreciation 12/31/2012 | 232 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSixZeroRanchoConejoBlvdMember |  |  |
1270 Rancho Conejo Blvd [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Thousand Oaks, CA |  |  |
Initial Cost of Land | 1,224 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenZeroRanchoConejoBlvdMember |  |  |
Building and Improvements | 716 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenZeroRanchoConejoBlvdMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 21 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenZeroRanchoConejoBlvdMember |  |  |
Land | 1,229 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenZeroRanchoConejoBlvdMember |  |  |
Building and improvements | 732 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenZeroRanchoConejoBlvdMember |  |  |
Total | 1,961 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenZeroRanchoConejoBlvdMember |  |  |
Accumulated depreciation 12/31/2012 | 305 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSevenZeroRanchoConejoBlvdMember |  |  |
1280 Rancho Conejo Blvd [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Thousand Oaks, CA |  |  |
Encumbrances | 2,861 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoEightZeroRanchoConejoBlvdMember |  |  |
Initial Cost of Land | 2,043 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoEightZeroRanchoConejoBlvdMember |  |  |
Building and Improvements | 3,408 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoEightZeroRanchoConejoBlvdMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (114)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoEightZeroRanchoConejoBlvdMember |  |  |
Land | 2,051 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoEightZeroRanchoConejoBlvdMember |  |  |
Building and improvements | 3,286 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoEightZeroRanchoConejoBlvdMember |  |  |
Total | 5,337 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoEightZeroRanchoConejoBlvdMember |  |  |
Accumulated depreciation 12/31/2012 | 682 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoEightZeroRanchoConejoBlvdMember |  |  |
1290 Rancho Conejo Blvd [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Thousand Oaks, CA |  |  |
Encumbrances | 2,416 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoNineZeroRanchoConejoBlvdMember |  |  |
Initial Cost of Land | 1,754 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoNineZeroRanchoConejoBlvdMember |  |  |
Building and Improvements | 2,949 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoNineZeroRanchoConejoBlvdMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (204)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoNineZeroRanchoConejoBlvdMember |  |  |
Land | 1,761 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoNineZeroRanchoConejoBlvdMember |  |  |
Building and improvements | 2,738 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoNineZeroRanchoConejoBlvdMember |  |  |
Total | 4,499 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoNineZeroRanchoConejoBlvdMember |  |  |
Accumulated depreciation 12/31/2012 | 594 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoNineZeroRanchoConejoBlvdMember |  |  |
100 West Sinclair Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Riverside, CA |  |  |
Initial Cost of Land | 4,894 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroZeroWestSinclairMember |  |  |
Building and Improvements | 3,481 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroZeroWestSinclairMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (5,233)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroZeroWestSinclairMember |  |  |
Land | 1,819 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroZeroWestSinclairMember |  |  |
Building and improvements | 1,323 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroZeroWestSinclairMember |  |  |
Total | 3,142 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroZeroWestSinclairMember |  |  |
Accumulated depreciation 12/31/2012 | 540 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroZeroWestSinclairMember |  |  |
14050 Day Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Moreno Valley, CA |  |  |
Encumbrances | 3,313 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourZeroFiveZeroDayStreetMember |  |  |
Initial Cost of Land | 2,538 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourZeroFiveZeroDayStreetMember |  |  |
Building and Improvements | 2,538 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourZeroFiveZeroDayStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 291 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourZeroFiveZeroDayStreetMember |  |  |
Land | 2,565 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourZeroFiveZeroDayStreetMember |  |  |
Building and improvements | 2,801 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourZeroFiveZeroDayStreetMember |  |  |
Total | 5,366 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourZeroFiveZeroDayStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 779 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneFourZeroFiveZeroDayStreetMember |  |  |
12925 Marlay Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Fontana, CA |  |  |
Encumbrances | 9,092 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoNineTwoFiveMarlayAvenueMember |  |  |
Initial Cost of Land | 6,072 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoNineTwoFiveMarlayAvenueMember |  |  |
Building and Improvements | 7,891 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoNineTwoFiveMarlayAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 762 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoNineTwoFiveMarlayAvenueMember |  |  |
Land | 6,090 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoNineTwoFiveMarlayAvenueMember |  |  |
Building and improvements | 8,635 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoNineTwoFiveMarlayAvenueMember |  |  |
Total | 14,725 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoNineTwoFiveMarlayAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 3,159 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoNineTwoFiveMarlayAvenueMember |  |  |
18201-18291 Santa Fe [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Rancho Dominguez, CA |  |  |
Encumbrances | 9,708 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightTwoZeroOneToOneEightTwoNineOneSantaFeMember |  |  |
Initial Cost of Land | 6,720 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightTwoZeroOneToOneEightTwoNineOneSantaFeMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 9,004 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightTwoZeroOneToOneEightTwoNineOneSantaFeMember |  |  |
Land | 6,897 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightTwoZeroOneToOneEightTwoNineOneSantaFeMember |  |  |
Building and improvements | 8,827 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightTwoZeroOneToOneEightTwoNineOneSantaFeMember |  |  |
Total | 15,724 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightTwoZeroOneToOneEightTwoNineOneSantaFeMember |  |  |
Accumulated depreciation 12/31/2012 | 1,636 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightTwoZeroOneToOneEightTwoNineOneSantaFeMember |  |  |
1011 Rancho Conejo [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Thousand Oaks, CA |  |  |
Encumbrances | 5,328 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroOneOneRanchoConejoMember |  |  |
Initial Cost of Land | 7,717 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroOneOneRanchoConejoMember |  |  |
Building and Improvements | 2,518 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroOneOneRanchoConejoMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (155)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroOneOneRanchoConejoMember |  |  |
Land | 7,752 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroOneOneRanchoConejoMember |  |  |
Building and improvements | 2,327 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroOneOneRanchoConejoMember |  |  |
Total | 10,079 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroOneOneRanchoConejoMember |  |  |
Accumulated depreciation 12/31/2012 | 1,000 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroOneOneRanchoConejoMember |  |  |
2300 Corporate Center Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Thousand Oaks, CA |  |  |
Initial Cost of Land | 6,506 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroZeroCorporateCenterDriveMember |  |  |
Building and Improvements | 4,885 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroZeroCorporateCenterDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (5,427)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroZeroCorporateCenterDriveMember |  |  |
Land | 3,236 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroZeroCorporateCenterDriveMember |  |  |
Building and improvements | 2,728 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroZeroCorporateCenterDriveMember |  |  |
Total | 5,964 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroZeroCorporateCenterDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 901 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoThreeZeroZeroCorporateCenterDriveMember |  |  |
20700 Denker Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Rancho Dominguez, CA |  |  |
Encumbrances |  | 5,280 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroSevenZeroZeroDenkerAvenueMember |  |
Initial Cost of Land | 5,767 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroSevenZeroZeroDenkerAvenueMember |  |  |
Building and Improvements | 2,538 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroSevenZeroZeroDenkerAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,282 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroSevenZeroZeroDenkerAvenueMember |  |  |
Land | 5,964 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroSevenZeroZeroDenkerAvenueMember |  |  |
Building and improvements | 3,624 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroSevenZeroZeroDenkerAvenueMember |  |  |
Total | 9,588 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroSevenZeroZeroDenkerAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 1,433 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroSevenZeroZeroDenkerAvenueMember |  |  |
18408 Laurel Park Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Rancho Dominguez, CA |  |  |
Initial Cost of Land | 2,850 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightFourZeroEightLaurelParkRoadMember |  |  |
Building and Improvements | 2,850 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightFourZeroEightLaurelParkRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 722 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightFourZeroEightLaurelParkRoadMember |  |  |
Land | 2,874 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightFourZeroEightLaurelParkRoadMember |  |  |
Building and improvements | 3,548 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightFourZeroEightLaurelParkRoadMember |  |  |
Total | 6,422 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightFourZeroEightLaurelParkRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 879 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneEightFourZeroEightLaurelParkRoadMember |  |  |
19021 S. Reyes Ave [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Rancho Dominguez, CA |  |  |
Initial Cost of Land | 8,183 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroTwoOneSReyesAvenueMember |  |  |
Building and Improvements | 7,501 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroTwoOneSReyesAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 761 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroTwoOneSReyesAvenueMember |  |  |
Land | 8,545 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroTwoOneSReyesAvenueMember |  |  |
Building and improvements | 7,900 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroTwoOneSReyesAvenueMember |  |  |
Total | 16,445 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroTwoOneSReyesAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 1,675 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneNineZeroTwoOneSReyesAvenueMember |  |  |
Six One Eight Five Kimball Ave [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Chino, CA |  |  |
Initial Cost of Land | 6,385 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixOneEightFiveKimballAveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 12,343 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixOneEightFiveKimballAveMember |  |  |
Land | 6,382 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixOneEightFiveKimballAveMember |  |  |
Building and improvements | 12,346 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixOneEightFiveKimballAveMember |  |  |
Total | 18,728 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixOneEightFiveKimballAveMember |  |  |
Accumulated depreciation 12/31/2012 | 796 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixOneEightFiveKimballAveMember |  |  |
Five Five Five Five Bandini Blvd [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Bell, CA |  |  |
Initial Cost of Land | 32,536 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveFiveFiveBandiniBlvdMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 20,917 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveFiveFiveBandiniBlvdMember |  |  |
Land | 32,540 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveFiveFiveBandiniBlvdMember |  |  |
Building and improvements | 20,913 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveFiveFiveBandiniBlvdMember |  |  |
Total | 53,453 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveFiveFiveBandiniBlvdMember |  |  |
Accumulated depreciation 12/31/2012 | 647 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveFiveFiveFiveBandiniBlvdMember |  |  |
Sixteen Thousand Eight Hundred Seventy Five Heacock Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Moreno Valley, CA |  |  |
Building and Improvements | 6,831 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixteenThousandEightHundredSeventyFiveHeacockStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 72 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixteenThousandEightHundredSeventyFiveHeacockStreetMember |  |  |
Building and improvements | 6,903 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixteenThousandEightHundredSeventyFiveHeacockStreetMember |  |  |
Total | 6,903 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixteenThousandEightHundredSeventyFiveHeacockStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 253 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixteenThousandEightHundredSeventyFiveHeacockStreetMember |  |  |
Four Thousand Seven Hundred Ten Guasti Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Ontario, CA |  |  |
Initial Cost of Land | 2,846 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandSevenHundredTenGuastiRoadMember |  |  |
Building and Improvements | 6,564 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandSevenHundredTenGuastiRoadMember |  |  |
Land | 2,846 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandSevenHundredTenGuastiRoadMember |  |  |
Building and improvements | 6,564 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandSevenHundredTenGuastiRoadMember |  |  |
Total | 9,410 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandSevenHundredTenGuastiRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 41 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FourThousandSevenHundredTenGuastiRoadMember |  |  |
Seventeen Thousand One Hundred Perris Boulevard [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Moreno Valley, CA |  |  |
Initial Cost of Land | 6,388 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SeventeenThousandOneHundredPerrisBoulevardMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 22,595 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SeventeenThousandOneHundredPerrisBoulevardMember |  |  |
Land | 6,395 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SeventeenThousandOneHundredPerrisBoulevardMember |  |  |
Building and improvements | 22,588 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SeventeenThousandOneHundredPerrisBoulevardMember |  |  |
Total | 28,983 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SeventeenThousandOneHundredPerrisBoulevardMember |  |  |
Accumulated depreciation 12/31/2012 | 356 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SeventeenThousandOneHundredPerrisBoulevardMember |  |  |
Thirteen Thousand Four Hundred Fourteen South Figueroa [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Los Angeles, CA |  |  |
Initial Cost of Land | 1,701 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThirteenThousandFourHundredFourteenSouthFigueroaMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 6,577 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThirteenThousandFourHundredFourteenSouthFigueroaMember |  |  |
Land | 1,887 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThirteenThousandFourHundredFourteenSouthFigueroaMember |  |  |
Building and improvements | 6,391 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThirteenThousandFourHundredFourteenSouthFigueroaMember |  |  |
Total | 8,278 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThirteenThousandFourHundredFourteenSouthFigueroaMember |  |  |
Accumulated depreciation 12/31/2012 | 88 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThirteenThousandFourHundredFourteenSouthFigueroaMember |  |  |
2060 Springdale Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Cherry Hill, NJ |  |  |
Initial Cost of Land | 258 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroSixZeroSpringdaleRoadMember |  |  |
Building and Improvements | 1,436 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroSixZeroSpringdaleRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 625 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroSixZeroSpringdaleRoadMember |  |  |
Land | 258 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroSixZeroSpringdaleRoadMember |  |  |
Building and improvements | 2,061 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroSixZeroSpringdaleRoadMember |  |  |
Total | 2,319 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroSixZeroSpringdaleRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 808 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_TwoZeroSixZeroSpringdaleRoadMember |  |  |
111 Whittendale Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Morrestown, NJ |  |  |
Initial Cost of Land | 522 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneOneWhittendaleDriveMember |  |  |
Building and Improvements | 2,916 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneOneWhittendaleDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 519 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneOneWhittendaleDriveMember |  |  |
Land | 522 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneOneWhittendaleDriveMember |  |  |
Building and improvements | 3,435 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneOneWhittendaleDriveMember |  |  |
Total | 3,957 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneOneWhittendaleDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,217 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneOneWhittendaleDriveMember |  |  |
7851 Airport Highway [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Pennsauken, NJ |  |  |
Initial Cost of Land | 160 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenEightFiveOneAirportHighwayMember |  |  |
Building and Improvements | 508 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenEightFiveOneAirportHighwayMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 381 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenEightFiveOneAirportHighwayMember |  |  |
Land | 162 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenEightFiveOneAirportHighwayMember |  |  |
Building and improvements | 887 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenEightFiveOneAirportHighwayMember |  |  |
Total | 1,049 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenEightFiveOneAirportHighwayMember |  |  |
Accumulated depreciation 12/31/2012 | 352 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenEightFiveOneAirportHighwayMember |  |  |
103 Central Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Mt. Laurel, NJ |  |  |
Initial Cost of Land | 610 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroThreeCentralMember |  |  |
Building and Improvements | 1,847 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroThreeCentralMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 1,471 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroThreeCentralMember |  |  |
Land | 619 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroThreeCentralMember |  |  |
Building and improvements | 3,309 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroThreeCentralMember |  |  |
Total | 3,928 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroThreeCentralMember |  |  |
Accumulated depreciation 12/31/2012 | 1,085 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroThreeCentralMember |  |  |
7890 Airport Hwy/7015 Central [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Pennsauken, NJ |  |  |
Initial Cost of Land | 300 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenEightNineZeroAirportHighwaySevenZeroOneFiveCentralMember |  |  |
Building and Improvements | 989 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenEightNineZeroAirportHighwaySevenZeroOneFiveCentralMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 543 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenEightNineZeroAirportHighwaySevenZeroOneFiveCentralMember |  |  |
Land | 425 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenEightNineZeroAirportHighwaySevenZeroOneFiveCentralMember |  |  |
Building and improvements | 1,407 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenEightNineZeroAirportHighwaySevenZeroOneFiveCentralMember |  |  |
Total | 1,832 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenEightNineZeroAirportHighwaySevenZeroOneFiveCentralMember |  |  |
Accumulated depreciation 12/31/2012 | 947 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenEightNineZeroAirportHighwaySevenZeroOneFiveCentralMember |  |  |
600 Creek Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Delanco, NJ |  |  |
Initial Cost of Land | 2,125 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixZeroZeroCreekRoadMember |  |  |
Building and Improvements | 6,504 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixZeroZeroCreekRoadMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (3,821)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixZeroZeroCreekRoadMember |  |  |
Land | 1,557 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixZeroZeroCreekRoadMember |  |  |
Building and improvements | 3,251 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixZeroZeroCreekRoadMember |  |  |
Total | 4,808 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixZeroZeroCreekRoadMember |  |  |
Accumulated depreciation 12/31/2012 | 746 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixZeroZeroCreekRoadMember |  |  |
6301 Hazeltine National Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Orlando, FL |  |  |
Initial Cost of Land | 909 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixThreeZeroOneHazeltineNationalDriveMember |  |  |
Building and Improvements | 4,613 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixThreeZeroOneHazeltineNationalDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 57 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixThreeZeroOneHazeltineNationalDriveMember |  |  |
Land | 920 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixThreeZeroOneHazeltineNationalDriveMember |  |  |
Building and improvements | 4,659 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixThreeZeroOneHazeltineNationalDriveMember |  |  |
Total | 5,579 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixThreeZeroOneHazeltineNationalDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 1,718 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixThreeZeroOneHazeltineNationalDriveMember |  |  |
12626 Silicon Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | San Antonio, TX |  |  |
Initial Cost of Land | 768 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSixTwoSixSiliconDriveMember |  |  |
Building and Improvements | 3,448 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSixTwoSixSiliconDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (449)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSixTwoSixSiliconDriveMember |  |  |
Land | 779 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSixTwoSixSiliconDriveMember |  |  |
Building and improvements | 2,988 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSixTwoSixSiliconDriveMember |  |  |
Total | 3,767 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSixTwoSixSiliconDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 934 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneTwoSixTwoSixSiliconDriveMember |  |  |
3100 Pinson Valley Parkway [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Birmingham, AL |  |  |
Initial Cost of Land | 303 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThousandOneHundredPinsonValleyParkwayMember |  |  |
Building and Improvements | 742 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThousandOneHundredPinsonValleyParkwayMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (280)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThousandOneHundredPinsonValleyParkwayMember |  |  |
Land | 225 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThousandOneHundredPinsonValleyParkwayMember |  |  |
Building and improvements | 540 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThousandOneHundredPinsonValleyParkwayMember |  |  |
Total | 765 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThousandOneHundredPinsonValleyParkwayMember |  |  |
Accumulated depreciation 12/31/2012 | 212 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThousandOneHundredPinsonValleyParkwayMember |  |  |
3730 Wheeler Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Fort Smith, AR |  |  |
Initial Cost of Land | 720 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeSevenThreeZeroWheelerAvenueMember |  |  |
Building and Improvements | 2,800 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeSevenThreeZeroWheelerAvenueMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (589)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeSevenThreeZeroWheelerAvenueMember |  |  |
Land | 583 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeSevenThreeZeroWheelerAvenueMember |  |  |
Building and improvements | 2,348 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeSevenThreeZeroWheelerAvenueMember |  |  |
Total | 2,931 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeSevenThreeZeroWheelerAvenueMember |  |  |
Accumulated depreciation 12/31/2012 | 827 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeSevenThreeZeroWheelerAvenueMember |  |  |
3200 Pond Station [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Jefferson County, KY |  |  |
Initial Cost of Land | 2,074 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThousandTwoHundredPondStationMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 9,896 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThousandTwoHundredPondStationMember |  |  |
Land | 2,120 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThousandTwoHundredPondStationMember |  |  |
Building and improvements | 9,850 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThousandTwoHundredPondStationMember |  |  |
Total | 11,970 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThousandTwoHundredPondStationMember |  |  |
Accumulated depreciation 12/31/2012 | 2,052 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeThousandTwoHundredPondStationMember |  |  |
7501 NW 106th Terrace [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Kansas City, MO |  |  |
Encumbrances | 10,997 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFiveZeroOneNwOneZeroSixthTerraceMember |  |  |
Initial Cost of Land | 4,152 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFiveZeroOneNwOneZeroSixthTerraceMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 13,659 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFiveZeroOneNwOneZeroSixthTerraceMember |  |  |
Land | 4,228 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFiveZeroOneNwOneZeroSixthTerraceMember |  |  |
Building and improvements | 13,583 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFiveZeroOneNwOneZeroSixthTerraceMember |  |  |
Total | 17,811 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFiveZeroOneNwOneZeroSixthTerraceMember |  |  |
Accumulated depreciation 12/31/2012 | 2,108 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFiveZeroOneNwOneZeroSixthTerraceMember |  |  |
600 Greene Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Greenville, KY |  |  |
Initial Cost of Land | 294 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixHundredGreeneDriveMember |  |  |
Building and Improvements | 8,570 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixHundredGreeneDriveMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | (727)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixHundredGreeneDriveMember |  |  |
Land | 296 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixHundredGreeneDriveMember |  |  |
Building and improvements | 7,841 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixHundredGreeneDriveMember |  |  |
Total | 8,137 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixHundredGreeneDriveMember |  |  |
Accumulated depreciation 12/31/2012 | 4,094 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SixHundredGreeneDriveMember |  |  |
Developments / Land Parcels [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Initial Cost of Land | 159,831 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_RedevelopmentsDevelopementsDevelopableLandMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 5,930 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_RedevelopmentsDevelopementsDevelopableLandMember |  |  |
Land | 150,135 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_RedevelopmentsDevelopementsDevelopableLandMember |  |  |
Building and improvements | 15,626 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_RedevelopmentsDevelopementsDevelopableLandMember |  |  |
Total | 165,761 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_RedevelopmentsDevelopementsDevelopableLandMember |  |  |
Accumulated depreciation 12/31/2012 | 2,184 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_RedevelopmentsDevelopementsDevelopableLandMember |  |  |
Seven Four Five One Seven Four Seven Seven Airport Freeway [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Richland Hills, TX |  |  |
Encumbrances | 1,363 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourFiveOneSevenFourSevenSevenAirportFreewayMember |  |  |
Initial Cost of Land | 256 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourFiveOneSevenFourSevenSevenAirportFreewayMember |  |  |
Building and Improvements | 1,453 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourFiveOneSevenFourSevenSevenAirportFreewayMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 499 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourFiveOneSevenFourSevenSevenAirportFreewayMember |  |  |
Land | 259 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourFiveOneSevenFourSevenSevenAirportFreewayMember |  |  |
Building and improvements | 1,949 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourFiveOneSevenFourSevenSevenAirportFreewayMember |  |  |
Total | 2,208 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourFiveOneSevenFourSevenSevenAirportFreewayMember |  |  |
Accumulated depreciation 12/31/2012 | 625 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourFiveOneSevenFourSevenSevenAirportFreewayMember |  |  |
Seven Four Five Zero Whitehall Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Richland Hills, TX |  |  |
Initial Cost of Land | 104 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourFiveZeroWhitehallStreetMember |  |  |
Building and Improvements | 591 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourFiveZeroWhitehallStreetMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 339 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourFiveZeroWhitehallStreetMember |  |  |
Land | 105 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourFiveZeroWhitehallStreetMember |  |  |
Building and improvements | 929 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourFiveZeroWhitehallStreetMember |  |  |
Total | 1,034 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourFiveZeroWhitehallStreetMember |  |  |
Accumulated depreciation 12/31/2012 | 250 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourFiveZeroWhitehallStreetMember |  |  |
Three Zero Zero Zero Wesley Way [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Richland Hills, TX |  |  |
Initial Cost of Land | 208 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroZeroZeroWesleyWayMember |  |  |
Building and Improvements | 1,181 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroZeroZeroWesleyWayMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 18 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroZeroZeroWesleyWayMember |  |  |
Land | 211 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroZeroZeroWesleyWayMember |  |  |
Building and improvements | 1,196 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroZeroZeroWesleyWayMember |  |  |
Total | 1,407 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroZeroZeroWesleyWayMember |  |  |
Accumulated depreciation 12/31/2012 | 367 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_ThreeZeroZeroZeroWesleyWayMember |  |  |
Seven Four Five One Dogwood Park [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Richland Hills, TX |  |  |
Encumbrances | 666 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourFiveOneDogwoodParkMember |  |  |
Initial Cost of Land | 133 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourFiveOneDogwoodParkMember |  |  |
Building and Improvements | 753 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourFiveOneDogwoodParkMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 184 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourFiveOneDogwoodParkMember |  |  |
Land | 134 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourFiveOneDogwoodParkMember |  |  |
Building and improvements | 936 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourFiveOneDogwoodParkMember |  |  |
Total | 1,070 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourFiveOneDogwoodParkMember |  |  |
Accumulated depreciation 12/31/2012 | 258 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_SevenFourFiveOneDogwoodParkMember |  |  |
One Zero One Three Three One Avenue M [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Grand Prairie, TX |  |  |
Initial Cost of Land | 300 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroOneThreeThreeOneAvenueMMember |  |  |
Building and Improvements | 1,504 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroOneThreeThreeOneAvenueMMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 240 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroOneThreeThreeOneAvenueMMember |  |  |
Land | 302 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroOneThreeThreeOneAvenueMMember |  |  |
Building and improvements | 1,742 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroOneThreeThreeOneAvenueMMember |  |  |
Total | 2,044 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroOneThreeThreeOneAvenueMMember |  |  |
Accumulated depreciation 12/31/2012 | 573 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneZeroOneThreeThreeOneAvenueMMember |  |  |
One One Seven Two Eight Four One One Three Th Street D [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Grand Prairie, TX |  |  |
Encumbrances | 1,933 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneSevenTwoEightFourOneOneThreeThStreetDMember |  |  |
Initial Cost of Land | 700 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneSevenTwoEightFourOneOneThreeThStreetDMember |  |  |
Building and Improvements | 3,509 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneSevenTwoEightFourOneOneThreeThStreetDMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 5 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneSevenTwoEightFourOneOneThreeThStreetDMember |  |  |
Land | 704 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneSevenTwoEightFourOneOneThreeThStreetDMember |  |  |
Building and improvements | 3,510 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneSevenTwoEightFourOneOneThreeThStreetDMember |  |  |
Total | 4,214 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneSevenTwoEightFourOneOneThreeThStreetDMember |  |  |
Accumulated depreciation 12/31/2012 | 1,239 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_OneOneSevenTwoEightFourOneOneThreeThStreetDMember |  |  |
Five Eight One Welltown Road Tyson Blvd [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Location (City/State) | Winchester, VA |  |  |
Initial Cost of Land | 2,320 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveEightOneWelltownRoadTysonBlvdMember |  |  |
Costs capitalized subsequent to acquisition or completion and valuation provision | 10,945 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveEightOneWelltownRoadTysonBlvdMember |  |  |
Land | 2,401 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveEightOneWelltownRoadTysonBlvdMember |  |  |
Building and improvements | 10,864 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveEightOneWelltownRoadTysonBlvdMember |  |  |
Total | 13,265 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveEightOneWelltownRoadTysonBlvdMember |  |  |
Accumulated depreciation 12/31/2012 | $ 2,054 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = fr_FiveEightOneWelltownRoadTysonBlvdMember |  |  |

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- Definition SEC Schedule III, Real Estate and Accumulated Depreciation, Location City and State + References No definition available. + Details
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- Definition Amount of accumulated depreciation pertaining to real estate investments for entities with a substantial portion of business acquiring and holding investment real estate. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 970 -SubTopic 360 -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-28.FN4) -URI http://asc.fasb.org/extlink&oid=6590653&loc=d3e638233-123024 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 10 -Section S99 -Paragraph 6 -Subparagraph (SX 210.5-04.(c) Schedule III) -URI http://asc.fasb.org/extlink&oid=27047687&loc=d3e5864-122674 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 28 -Article 12 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph c -Subparagraph Schedule III -Article 5 + Details
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- Definition Amount of lien or mortgage outstanding on real estate investment properties for entities with a substantial portion of business acquiring and holding investment real estate. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 970 -SubTopic 360 -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-28) -URI http://asc.fasb.org/extlink&oid=6590653&loc=d3e638233-123024 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 10 -Section S99 -Paragraph 6 -Subparagraph (SX 210.5-04.(c) Schedule III) -URI http://asc.fasb.org/extlink&oid=27047687&loc=d3e5864-122674 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 28 -Article 12 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph c -Subparagraph Schedule III -Article 5 + Details
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- Definition Amount before accumulated depreciation of buildings and improvements for entities with a substantial portion of business acquiring and holding investment real estate. Excludes real estate not held as an investment or interest. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 970 -SubTopic 360 -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-28) -URI http://asc.fasb.org/extlink&oid=6590653&loc=d3e638233-123024 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 10 -Section S99 -Paragraph 6 -Subparagraph (SX 210.5-04.(c) Schedule III) -URI http://asc.fasb.org/extlink&oid=27047687&loc=d3e5864-122674 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 28 -Article 12 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph c -Subparagraph Schedule III -Article 5 + Details
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- Definition Amount of land for entities with a substantial portion of business acquiring and holding investment real estate. Excludes real estate not held as an investment or interest. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 970 -SubTopic 360 -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-28) -URI http://asc.fasb.org/extlink&oid=6590653&loc=d3e638233-123024 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 10 -Section S99 -Paragraph 6 -Subparagraph (SX 210.5-04.(c) Schedule III) -URI http://asc.fasb.org/extlink&oid=27047687&loc=d3e5864-122674 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 28 -Article 12 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph c -Subparagraph Schedule III -Article 5 + Details
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- Definition Amount of carrying costs of properties that were capitalized after acquisition, for example, but not limited to, real estate taxes and insurance for entities with a substantial portion of business acquiring and holding investment real estate. Excludes initial purchase price and improvements. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 970 -SubTopic 360 -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-28) -URI http://asc.fasb.org/extlink&oid=6590653&loc=d3e638233-123024 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 10 -Section S99 -Paragraph 6 -Subparagraph (SX 210.5-04.(c) Schedule III) -URI http://asc.fasb.org/extlink&oid=27047687&loc=d3e5864-122674 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 28 -Article 12 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph c -Subparagraph Schedule III -Article 5 + Details
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