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Schedule III - Real Estate and Accumulated Depreciation (Details) (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 at December 31, 2012 | $ 655,934 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 625,594 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand |  |  |
Buildings and Improvements | 3,362,277 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements |  |  |
Net Improvements (Retirements) Since Acquisition | 643,257 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 673,838 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand |  |  |
Buildings and Improvements | 3,957,290 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements |  |  |
Total | 4,631,128 us-gaap_RealEstateGrossAtCarryingValue | 4,669,289 us-gaap_RealEstateGrossAtCarryingValue | 4,726,169 us-gaap_RealEstateGrossAtCarryingValue | 4,793,080 us-gaap_RealEstateGrossAtCarryingValue
Accumulated Depreciation at December 31, 2013 | 1,078,996 us-gaap_RealEstateAccumulatedDepreciation | 983,808 us-gaap_RealEstateAccumulatedDepreciation | 954,665 us-gaap_RealEstateAccumulatedDepreciation | 865,710 us-gaap_RealEstateAccumulatedDepreciation
400 Berwyn Park [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A400BerwynParkMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,657 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A400BerwynParkMember |  |  |
Buildings and Improvements | 4,462 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A400BerwynParkMember |  |  |
Net Improvements (Retirements) Since Acquisition | 14,011 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A400BerwynParkMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,657 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A400BerwynParkMember |  |  |
Buildings and Improvements | 18,473 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A400BerwynParkMember |  |  |
Total | 21,130 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A400BerwynParkMember |  |  |
Accumulated Depreciation at December 31, 2013 | 6,255 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A400BerwynParkMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
300 Berwyn Park [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A300BerwynParkMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,206 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A300BerwynParkMember |  |  |
Buildings and Improvements | 13,422 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A300BerwynParkMember |  |  |
Net Improvements (Retirements) Since Acquisition | 3,800 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A300BerwynParkMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,206 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A300BerwynParkMember |  |  |
Buildings and Improvements | 17,222 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A300BerwynParkMember |  |  |
Total | 19,428 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A300BerwynParkMember |  |  |
Accumulated Depreciation at December 31, 2013 | 8,280 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A300BerwynParkMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
1050 Westlakes Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1050WestlakesDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,611 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1050WestlakesDriveMember |  |  |
Buildings and Improvements | 10,445 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1050WestlakesDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 5,047 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1050WestlakesDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,611 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1050WestlakesDriveMember |  |  |
Buildings and Improvements | 15,492 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1050WestlakesDriveMember |  |  |
Total | 18,103 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1050WestlakesDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 7,984 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1050WestlakesDriveMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
1200 Swedesford Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1200SwedesfordRoadMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,595 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1200SwedesfordRoadMember |  |  |
Buildings and Improvements | 11,809 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1200SwedesfordRoadMember |  |  |
Net Improvements (Retirements) Since Acquisition | 3,534 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1200SwedesfordRoadMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,595 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1200SwedesfordRoadMember |  |  |
Buildings and Improvements | 15,343 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1200SwedesfordRoadMember |  |  |
Total | 17,938 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1200SwedesfordRoadMember |  |  |
Accumulated Depreciation at December 31, 2013 | 6,457 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1200SwedesfordRoadMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
200 Berwyn Park [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A200BerwynParkMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,533 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A200BerwynParkMember |  |  |
Buildings and Improvements | 9,460 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A200BerwynParkMember |  |  |
Net Improvements (Retirements) Since Acquisition | 2,466 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A200BerwynParkMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,533 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A200BerwynParkMember |  |  |
Buildings and Improvements | 11,926 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A200BerwynParkMember |  |  |
Total | 13,459 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A200BerwynParkMember |  |  |
Accumulated Depreciation at December 31, 2013 | 5,751 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A200BerwynParkMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
1180 Swedesford Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1180SwedesfordRoadMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,086 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1180SwedesfordRoadMember |  |  |
Buildings and Improvements | 8,342 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1180SwedesfordRoadMember |  |  |
Net Improvements (Retirements) Since Acquisition | 2,979 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1180SwedesfordRoadMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,086 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1180SwedesfordRoadMember |  |  |
Buildings and Improvements | 11,321 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1180SwedesfordRoadMember |  |  |
Total | 13,407 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1180SwedesfordRoadMember |  |  |
Accumulated Depreciation at December 31, 2013 | 3,441 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1180SwedesfordRoadMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
100 Berwyn Park [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A100BerwynParkMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,180 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A100BerwynParkMember |  |  |
Buildings and Improvements | 7,290 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A100BerwynParkMember |  |  |
Net Improvements (Retirements) Since Acquisition | 2,228 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A100BerwynParkMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,180 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A100BerwynParkMember |  |  |
Buildings and Improvements | 9,518 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A100BerwynParkMember |  |  |
Total | 10,698 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A100BerwynParkMember |  |  |
Accumulated Depreciation at December 31, 2013 | 4,661 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A100BerwynParkMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
1160 Swedesford Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1160SwedesfordRoadMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,781 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1160SwedesfordRoadMember |  |  |
Buildings and Improvements | 7,124 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1160SwedesfordRoadMember |  |  |
Net Improvements (Retirements) Since Acquisition | 4,255 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1160SwedesfordRoadMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,045 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1160SwedesfordRoadMember |  |  |
Buildings and Improvements | 11,115 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1160SwedesfordRoadMember |  |  |
Total | 13,160 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1160SwedesfordRoadMember |  |  |
Accumulated Depreciation at December 31, 2013 | 2,961 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1160SwedesfordRoadMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
1100 Cassett Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1100CassettRoadMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,695 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1100CassettRoadMember |  |  |
Buildings and Improvements | 6,779 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1100CassettRoadMember |  |  |
Net Improvements (Retirements) Since Acquisition | 1,269 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1100CassettRoadMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,695 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1100CassettRoadMember |  |  |
Buildings and Improvements | 8,048 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1100CassettRoadMember |  |  |
Total | 9,743 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1100CassettRoadMember |  |  |
Accumulated Depreciation at December 31, 2013 | 2,561 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1100CassettRoadMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
980 Harvest Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A980HarvestDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,079 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A980HarvestDriveMember |  |  |
Buildings and Improvements | 8,315 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A980HarvestDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 736 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A980HarvestDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,079 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A980HarvestDriveMember |  |  |
Buildings and Improvements | 9,051 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A980HarvestDriveMember |  |  |
Total | 11,130 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A980HarvestDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 2,935 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A980HarvestDriveMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
910 Harvest Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A910HarvestDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,224 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A910HarvestDriveMember |  |  |
Buildings and Improvements | 8,645 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A910HarvestDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | (730)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A910HarvestDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,224 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A910HarvestDriveMember |  |  |
Buildings and Improvements | 7,915 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A910HarvestDriveMember |  |  |
Total | 9,139 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A910HarvestDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 4,394 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A910HarvestDriveMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
925 Harvest Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A925HarvestDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,671 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A925HarvestDriveMember |  |  |
Buildings and Improvements | 6,606 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A925HarvestDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 993 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A925HarvestDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,671 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A925HarvestDriveMember |  |  |
Buildings and Improvements | 7,599 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A925HarvestDriveMember |  |  |
Total | 9,270 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A925HarvestDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 3,480 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A925HarvestDriveMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
920 Harvest Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A920HarvestDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,209 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A920HarvestDriveMember |  |  |
Buildings and Improvements | 6,595 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A920HarvestDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | (684)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A920HarvestDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,209 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A920HarvestDriveMember |  |  |
Buildings and Improvements | 5,911 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A920HarvestDriveMember |  |  |
Total | 7,120 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A920HarvestDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 3,134 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A920HarvestDriveMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
Six Tower Bridge [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_SixTowerBridgeMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 6,927 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_SixTowerBridgeMember |  |  |
Buildings and Improvements | 14,722 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_SixTowerBridgeMember |  |  |
Net Improvements (Retirements) Since Acquisition | 786 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_SixTowerBridgeMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 6,927 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_SixTowerBridgeMember |  |  |
Buildings and Improvements | 15,508 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_SixTowerBridgeMember |  |  |
Total | 22,435 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_SixTowerBridgeMember |  |  |
Accumulated Depreciation at December 31, 2013 | 698 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_SixTowerBridgeMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
426 Lancaster Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A426LancasterAvenueMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,689 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A426LancasterAvenueMember |  |  |
Buildings and Improvements | 6,756 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A426LancasterAvenueMember |  |  |
Net Improvements (Retirements) Since Acquisition | 376 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A426LancasterAvenueMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,689 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A426LancasterAvenueMember |  |  |
Buildings and Improvements | 7,132 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A426LancasterAvenueMember |  |  |
Total | 8,821 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A426LancasterAvenueMember |  |  |
Accumulated Depreciation at December 31, 2013 | 3,431 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A426LancasterAvenueMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
52 Swedesford Square [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A52SwedesfordSquareMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 4,241 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A52SwedesfordSquareMember |  |  |
Buildings and Improvements | 16,579 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A52SwedesfordSquareMember |  |  |
Net Improvements (Retirements) Since Acquisition | 3,262 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A52SwedesfordSquareMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 4,241 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A52SwedesfordSquareMember |  |  |
Buildings and Improvements | 19,841 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A52SwedesfordSquareMember |  |  |
Total | 24,082 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A52SwedesfordSquareMember |  |  |
Accumulated Depreciation at December 31, 2013 | 8,392 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A52SwedesfordSquareMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
One Progress Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OneProgressDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,399 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OneProgressDriveMember |  |  |
Buildings and Improvements | 5,629 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OneProgressDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 5,202 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OneProgressDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,399 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OneProgressDriveMember |  |  |
Buildings and Improvements | 10,831 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OneProgressDriveMember |  |  |
Total | 12,230 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OneProgressDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 4,457 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OneProgressDriveMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
500 Enterprise Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A500EnterpriseDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,303 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A500EnterpriseDriveMember |  |  |
Buildings and Improvements | 5,188 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A500EnterpriseDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 3,743 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A500EnterpriseDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,303 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A500EnterpriseDriveMember |  |  |
Buildings and Improvements | 8,931 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A500EnterpriseDriveMember |  |  |
Total | 10,234 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A500EnterpriseDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 4,098 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A500EnterpriseDriveMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
640 Freedom Business Center [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A640FreedomBusinessCenterMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 4,222 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A640FreedomBusinessCenterMember |  |  |
Buildings and Improvements | 16,891 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A640FreedomBusinessCenterMember |  |  |
Net Improvements (Retirements) Since Acquisition | 4,686 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A640FreedomBusinessCenterMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 4,222 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A640FreedomBusinessCenterMember |  |  |
Buildings and Improvements | 21,577 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A640FreedomBusinessCenterMember |  |  |
Total | 25,799 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A640FreedomBusinessCenterMember |  |  |
Accumulated Depreciation at December 31, 2013 | 9,535 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A640FreedomBusinessCenterMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
555 Croton Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A555CrotonRoadMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 4,486 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A555CrotonRoadMember |  |  |
Buildings and Improvements | 17,943 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A555CrotonRoadMember |  |  |
Net Improvements (Retirements) Since Acquisition | 1,412 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A555CrotonRoadMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 4,486 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A555CrotonRoadMember |  |  |
Buildings and Improvements | 19,355 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A555CrotonRoadMember |  |  |
Total | 23,841 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A555CrotonRoadMember |  |  |
Accumulated Depreciation at December 31, 2013 | 6,779 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A555CrotonRoadMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
630 Allendale Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A630AllendaleRoadMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,836 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A630AllendaleRoadMember |  |  |
Buildings and Improvements | 4,028 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A630AllendaleRoadMember |  |  |
Net Improvements (Retirements) Since Acquisition | 12,484 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A630AllendaleRoadMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,898 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A630AllendaleRoadMember |  |  |
Buildings and Improvements | 16,450 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A630AllendaleRoadMember |  |  |
Total | 19,348 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A630AllendaleRoadMember |  |  |
Accumulated Depreciation at December 31, 2013 | 5,778 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A630AllendaleRoadMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
620 Freedom Business Center [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A620FreedomBusinessCenterMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,770 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A620FreedomBusinessCenterMember |  |  |
Buildings and Improvements | 11,014 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A620FreedomBusinessCenterMember |  |  |
Net Improvements (Retirements) Since Acquisition | 3,375 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A620FreedomBusinessCenterMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,770 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A620FreedomBusinessCenterMember |  |  |
Buildings and Improvements | 14,389 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A620FreedomBusinessCenterMember |  |  |
Total | 17,159 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A620FreedomBusinessCenterMember |  |  |
Accumulated Depreciation at December 31, 2013 | 7,515 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A620FreedomBusinessCenterMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
1000 First Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1000FirstAvenueMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,772 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1000FirstAvenueMember |  |  |
Buildings and Improvements | 10,936 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1000FirstAvenueMember |  |  |
Net Improvements (Retirements) Since Acquisition | 2,117 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1000FirstAvenueMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,772 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1000FirstAvenueMember |  |  |
Buildings and Improvements | 13,053 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1000FirstAvenueMember |  |  |
Total | 15,825 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1000FirstAvenueMember |  |  |
Accumulated Depreciation at December 31, 2013 | 5,894 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1000FirstAvenueMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
1060 First Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1060FirstAvenueMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,712 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1060FirstAvenueMember |  |  |
Buildings and Improvements | 10,953 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1060FirstAvenueMember |  |  |
Net Improvements (Retirements) Since Acquisition | 4,522 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1060FirstAvenueMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,712 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1060FirstAvenueMember |  |  |
Buildings and Improvements | 15,475 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1060FirstAvenueMember |  |  |
Total | 18,187 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1060FirstAvenueMember |  |  |
Accumulated Depreciation at December 31, 2013 | 6,646 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1060FirstAvenueMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
630 Freedom Business Center [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A630FreedomBusinessCenterMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,773 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A630FreedomBusinessCenterMember |  |  |
Buildings and Improvements | 11,144 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A630FreedomBusinessCenterMember |  |  |
Net Improvements (Retirements) Since Acquisition | 2,343 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A630FreedomBusinessCenterMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,773 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A630FreedomBusinessCenterMember |  |  |
Buildings and Improvements | 13,487 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A630FreedomBusinessCenterMember |  |  |
Total | 16,260 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A630FreedomBusinessCenterMember |  |  |
Accumulated Depreciation at December 31, 2013 | 6,300 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A630FreedomBusinessCenterMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
1040 First Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1040FirstAvenueMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,860 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1040FirstAvenueMember |  |  |
Buildings and Improvements | 11,282 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1040FirstAvenueMember |  |  |
Net Improvements (Retirements) Since Acquisition | 6,080 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1040FirstAvenueMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,860 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1040FirstAvenueMember |  |  |
Buildings and Improvements | 17,362 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1040FirstAvenueMember |  |  |
Total | 20,222 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1040FirstAvenueMember |  |  |
Accumulated Depreciation at December 31, 2013 | 5,460 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1040FirstAvenueMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
1020 First Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1020FirstAvenueMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,168 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1020FirstAvenueMember |  |  |
Buildings and Improvements | 8,576 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1020FirstAvenueMember |  |  |
Net Improvements (Retirements) Since Acquisition | 7,617 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1020FirstAvenueMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,168 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1020FirstAvenueMember |  |  |
Buildings and Improvements | 16,193 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1020FirstAvenueMember |  |  |
Total | 18,361 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1020FirstAvenueMember |  |  |
Accumulated Depreciation at December 31, 2013 | 6,766 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1020FirstAvenueMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
610 Freedom Business Center [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A610FreedomBusinessCenterMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,017 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A610FreedomBusinessCenterMember |  |  |
Buildings and Improvements | 8,070 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A610FreedomBusinessCenterMember |  |  |
Net Improvements (Retirements) Since Acquisition | 2,393 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A610FreedomBusinessCenterMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,017 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A610FreedomBusinessCenterMember |  |  |
Buildings and Improvements | 10,463 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A610FreedomBusinessCenterMember |  |  |
Total | 12,480 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A610FreedomBusinessCenterMember |  |  |
Accumulated Depreciation at December 31, 2013 | 4,883 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A610FreedomBusinessCenterMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
650 Park Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A650ParkAvenueMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,916 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A650ParkAvenueMember |  |  |
Buildings and Improvements | 4,378 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A650ParkAvenueMember |  |  |
Net Improvements (Retirements) Since Acquisition | 1,701 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A650ParkAvenueMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,916 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A650ParkAvenueMember |  |  |
Buildings and Improvements | 6,079 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A650ParkAvenueMember |  |  |
Total | 7,995 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A650ParkAvenueMember |  |  |
Accumulated Depreciation at December 31, 2013 | 2,920 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A650ParkAvenueMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
500 North Gulph Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A500NorthGulphRoadMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,303 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A500NorthGulphRoadMember |  |  |
Buildings and Improvements | 5,201 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A500NorthGulphRoadMember |  |  |
Net Improvements (Retirements) Since Acquisition | 1,522 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A500NorthGulphRoadMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,303 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A500NorthGulphRoadMember |  |  |
Buildings and Improvements | 6,723 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A500NorthGulphRoadMember |  |  |
Total | 8,026 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A500NorthGulphRoadMember |  |  |
Accumulated Depreciation at December 31, 2013 | 3,390 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A500NorthGulphRoadMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
741 First Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A741FirstAvenueMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,287 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A741FirstAvenueMember |  |  |
Buildings and Improvements | 5,151 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A741FirstAvenueMember |  |  |
Net Improvements (Retirements) Since Acquisition | 11 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A741FirstAvenueMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,287 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A741FirstAvenueMember |  |  |
Buildings and Improvements | 5,162 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A741FirstAvenueMember |  |  |
Total | 6,449 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A741FirstAvenueMember |  |  |
Accumulated Depreciation at December 31, 2013 | 2,363 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A741FirstAvenueMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
751-761 Fifth Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A751761FifthAvenueMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,097 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A751761FifthAvenueMember |  |  |
Buildings and Improvements | 4,391 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A751761FifthAvenueMember |  |  |
Net Improvements (Retirements) Since Acquisition | 31 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A751761FifthAvenueMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,097 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A751761FifthAvenueMember |  |  |
Buildings and Improvements | 4,422 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A751761FifthAvenueMember |  |  |
Total | 5,519 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A751761FifthAvenueMember |  |  |
Accumulated Depreciation at December 31, 2013 | 2,021 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A751761FifthAvenueMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
600 Park Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A600ParkAvenueMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,012 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A600ParkAvenueMember |  |  |
Buildings and Improvements | 4,048 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A600ParkAvenueMember |  |  |
Net Improvements (Retirements) Since Acquisition | 385 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A600ParkAvenueMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,012 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A600ParkAvenueMember |  |  |
Buildings and Improvements | 4,433 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A600ParkAvenueMember |  |  |
Total | 5,445 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A600ParkAvenueMember |  |  |
Accumulated Depreciation at December 31, 2013 | 2,045 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A600ParkAvenueMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
620 Allendale Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A620AllendaleRoadMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,020 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A620AllendaleRoadMember |  |  |
Buildings and Improvements | 3,839 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A620AllendaleRoadMember |  |  |
Net Improvements (Retirements) Since Acquisition | 658 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A620AllendaleRoadMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,020 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A620AllendaleRoadMember |  |  |
Buildings and Improvements | 4,497 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A620AllendaleRoadMember |  |  |
Total | 5,517 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A620AllendaleRoadMember |  |  |
Accumulated Depreciation at December 31, 2013 | 2,008 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A620AllendaleRoadMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
660 Allendale Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A660AllendaleRoadMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 396 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A660AllendaleRoadMember |  |  |
Buildings and Improvements | 948 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A660AllendaleRoadMember |  |  |
Net Improvements (Retirements) Since Acquisition | 2,957 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A660AllendaleRoadMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,085 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A660AllendaleRoadMember |  |  |
Buildings and Improvements | 3,216 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A660AllendaleRoadMember |  |  |
Total | 4,301 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A660AllendaleRoadMember |  |  |
Accumulated Depreciation at December 31, 2013 | 921 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A660AllendaleRoadMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
640 Allendale Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A640AllendaleRoadMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 439 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A640AllendaleRoadMember |  |  |
Buildings and Improvements | 432 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A640AllendaleRoadMember |  |  |
Net Improvements (Retirements) Since Acquisition | 1,580 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A640AllendaleRoadMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 439 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A640AllendaleRoadMember |  |  |
Buildings and Improvements | 2,012 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A640AllendaleRoadMember |  |  |
Total | 2,451 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A640AllendaleRoadMember |  |  |
Accumulated Depreciation at December 31, 2013 | 802 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A640AllendaleRoadMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
14 Campus Boulevard [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A14CampusBoulevardMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,244 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A14CampusBoulevardMember |  |  |
Buildings and Improvements | 4,217 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A14CampusBoulevardMember |  |  |
Net Improvements (Retirements) Since Acquisition | 1,533 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A14CampusBoulevardMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,244 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A14CampusBoulevardMember |  |  |
Buildings and Improvements | 5,750 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A14CampusBoulevardMember |  |  |
Total | 7,994 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A14CampusBoulevardMember |  |  |
Accumulated Depreciation at December 31, 2013 | 3,322 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A14CampusBoulevardMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
11 Campus Boulevard [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11CampusBoulevardMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,112 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11CampusBoulevardMember |  |  |
Buildings and Improvements | 4,067 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11CampusBoulevardMember |  |  |
Net Improvements (Retirements) Since Acquisition | 1,006 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11CampusBoulevardMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,112 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11CampusBoulevardMember |  |  |
Buildings and Improvements | 5,073 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11CampusBoulevardMember |  |  |
Total | 6,185 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11CampusBoulevardMember |  |  |
Accumulated Depreciation at December 31, 2013 | 1,967 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11CampusBoulevardMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
17 Campus Boulevard [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A17CampusBoulevardMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,108 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A17CampusBoulevardMember |  |  |
Buildings and Improvements | 5,155 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A17CampusBoulevardMember |  |  |
Net Improvements (Retirements) Since Acquisition | (374)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A17CampusBoulevardMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,108 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A17CampusBoulevardMember |  |  |
Buildings and Improvements | 4,781 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A17CampusBoulevardMember |  |  |
Total | 5,889 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A17CampusBoulevardMember |  |  |
Accumulated Depreciation at December 31, 2013 | 1,728 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A17CampusBoulevardMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
15 Campus Boulevard [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A15CampusBoulevardMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,164 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A15CampusBoulevardMember |  |  |
Buildings and Improvements | 3,896 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A15CampusBoulevardMember |  |  |
Net Improvements (Retirements) Since Acquisition | 249 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A15CampusBoulevardMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,164 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A15CampusBoulevardMember |  |  |
Buildings and Improvements | 4,145 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A15CampusBoulevardMember |  |  |
Total | 5,309 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A15CampusBoulevardMember |  |  |
Accumulated Depreciation at December 31, 2013 | 1,394 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A15CampusBoulevardMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
18 Campus Boulevard [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A18CampusBoulevardMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 787 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A18CampusBoulevardMember |  |  |
Buildings and Improvements | 3,312 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A18CampusBoulevardMember |  |  |
Net Improvements (Retirements) Since Acquisition | (77)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A18CampusBoulevardMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 787 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A18CampusBoulevardMember |  |  |
Buildings and Improvements | 3,235 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A18CampusBoulevardMember |  |  |
Total | 4,022 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A18CampusBoulevardMember |  |  |
Accumulated Depreciation at December 31, 2013 | 1,631 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A18CampusBoulevardMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
401 Plymouth Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A401PlymouthRoadMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 6,198 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A401PlymouthRoadMember |  |  |
Buildings and Improvements | 16,131 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A401PlymouthRoadMember |  |  |
Net Improvements (Retirements) Since Acquisition | 16,130 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A401PlymouthRoadMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 6,198 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A401PlymouthRoadMember |  |  |
Buildings and Improvements | 32,261 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A401PlymouthRoadMember |  |  |
Total | 38,459 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A401PlymouthRoadMember |  |  |
Accumulated Depreciation at December 31, 2013 | 9,982 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A401PlymouthRoadMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
4000 Chemical Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4000ChemicalRoadMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 4,373 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4000ChemicalRoadMember |  |  |
Buildings and Improvements | 24,546 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4000ChemicalRoadMember |  |  |
Net Improvements (Retirements) Since Acquisition | 1,467 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4000ChemicalRoadMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 4,373 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4000ChemicalRoadMember |  |  |
Buildings and Improvements | 26,013 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4000ChemicalRoadMember |  |  |
Total | 30,386 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4000ChemicalRoadMember |  |  |
Accumulated Depreciation at December 31, 2013 | 4,864 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4000ChemicalRoadMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
610 West Germantown Pike [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A610WestGermantownPikeMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 3,651 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A610WestGermantownPikeMember |  |  |
Buildings and Improvements | 14,514 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A610WestGermantownPikeMember |  |  |
Net Improvements (Retirements) Since Acquisition | 3,357 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A610WestGermantownPikeMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 3,651 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A610WestGermantownPikeMember |  |  |
Buildings and Improvements | 17,871 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A610WestGermantownPikeMember |  |  |
Total | 21,522 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A610WestGermantownPikeMember |  |  |
Accumulated Depreciation at December 31, 2013 | 5,892 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A610WestGermantownPikeMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
600 West Germantown Pike [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A600WestGermantownPikeMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 3,652 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A600WestGermantownPikeMember |  |  |
Buildings and Improvements | 15,288 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A600WestGermantownPikeMember |  |  |
Net Improvements (Retirements) Since Acquisition | 1,609 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A600WestGermantownPikeMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 3,652 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A600WestGermantownPikeMember |  |  |
Buildings and Improvements | 16,897 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A600WestGermantownPikeMember |  |  |
Total | 20,549 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A600WestGermantownPikeMember |  |  |
Accumulated Depreciation at December 31, 2013 | 5,659 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A600WestGermantownPikeMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
630 West Germantown Pike [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A630WestGermantownPikeMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 3,558 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A630WestGermantownPikeMember |  |  |
Buildings and Improvements | 14,743 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A630WestGermantownPikeMember |  |  |
Net Improvements (Retirements) Since Acquisition | 1,902 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A630WestGermantownPikeMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 3,558 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A630WestGermantownPikeMember |  |  |
Buildings and Improvements | 16,645 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A630WestGermantownPikeMember |  |  |
Total | 20,203 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A630WestGermantownPikeMember |  |  |
Accumulated Depreciation at December 31, 2013 | 5,994 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A630WestGermantownPikeMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
620 West Germantown Pike [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A620WestGermantownPikeMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 3,572 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A620WestGermantownPikeMember |  |  |
Buildings and Improvements | 14,435 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A620WestGermantownPikeMember |  |  |
Net Improvements (Retirements) Since Acquisition | 1,339 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A620WestGermantownPikeMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 3,572 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A620WestGermantownPikeMember |  |  |
Buildings and Improvements | 15,774 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A620WestGermantownPikeMember |  |  |
Total | 19,346 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A620WestGermantownPikeMember |  |  |
Accumulated Depreciation at December 31, 2013 | 5,378 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A620WestGermantownPikeMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
660 West Germantown Pike [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A660WestGermantownPikeMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 3,694 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A660WestGermantownPikeMember |  |  |
Buildings and Improvements | 5,487 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A660WestGermantownPikeMember |  |  |
Net Improvements (Retirements) Since Acquisition | 18,484 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A660WestGermantownPikeMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 5,404 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A660WestGermantownPikeMember |  |  |
Buildings and Improvements | 22,261 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A660WestGermantownPikeMember |  |  |
Total | 27,665 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A660WestGermantownPikeMember |  |  |
Accumulated Depreciation at December 31, 2013 | 1,436 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A660WestGermantownPikeMember |  |  |
Depreciable Life (Years) | 30 years |  |  |
2240/2250 Butler Pike [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A22402250ButlerPikeMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,104 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A22402250ButlerPikeMember |  |  |
Buildings and Improvements | 4,627 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A22402250ButlerPikeMember |  |  |
Net Improvements (Retirements) Since Acquisition | 1,312 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A22402250ButlerPikeMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,104 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A22402250ButlerPikeMember |  |  |
Buildings and Improvements | 5,939 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A22402250ButlerPikeMember |  |  |
Total | 7,043 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A22402250ButlerPikeMember |  |  |
Accumulated Depreciation at December 31, 2013 | 3,596 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A22402250ButlerPikeMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
2260 Butler Pike [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2260ButlerPikeMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 661 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2260ButlerPikeMember |  |  |
Buildings and Improvements | 2,727 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2260ButlerPikeMember |  |  |
Net Improvements (Retirements) Since Acquisition | 2,115 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2260ButlerPikeMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 661 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2260ButlerPikeMember |  |  |
Buildings and Improvements | 4,842 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2260ButlerPikeMember |  |  |
Total | 5,503 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2260ButlerPikeMember |  |  |
Accumulated Depreciation at December 31, 2013 | 2,165 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2260ButlerPikeMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
120 West Germantown Pike [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A120WestGermantownPikeMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 685 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A120WestGermantownPikeMember |  |  |
Buildings and Improvements | 2,773 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A120WestGermantownPikeMember |  |  |
Net Improvements (Retirements) Since Acquisition | 729 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A120WestGermantownPikeMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 685 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A120WestGermantownPikeMember |  |  |
Buildings and Improvements | 3,502 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A120WestGermantownPikeMember |  |  |
Total | 4,187 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A120WestGermantownPikeMember |  |  |
Accumulated Depreciation at December 31, 2013 | 1,767 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A120WestGermantownPikeMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
140 West Germantown Pike [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A140WestGermantownPikeMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 481 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A140WestGermantownPikeMember |  |  |
Buildings and Improvements | 1,976 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A140WestGermantownPikeMember |  |  |
Net Improvements (Retirements) Since Acquisition | 282 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A140WestGermantownPikeMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 481 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A140WestGermantownPikeMember |  |  |
Buildings and Improvements | 2,258 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A140WestGermantownPikeMember |  |  |
Total | 2,739 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A140WestGermantownPikeMember |  |  |
Accumulated Depreciation at December 31, 2013 | 1,079 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A140WestGermantownPikeMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
351 Plymouth Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A351PlymouthRoadMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,043 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A351PlymouthRoadMember |  |  |
Buildings and Improvements | 555 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A351PlymouthRoadMember |  |  |
Net Improvements (Retirements) Since Acquisition | 0 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A351PlymouthRoadMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,043 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A351PlymouthRoadMember |  |  |
Buildings and Improvements | 555 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A351PlymouthRoadMember |  |  |
Total | 1,598 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A351PlymouthRoadMember |  |  |
Accumulated Depreciation at December 31, 2013 | 135 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A351PlymouthRoadMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
150 Radnor Chester Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A150RadnorChesterRoadMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 11,925 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A150RadnorChesterRoadMember |  |  |
Buildings and Improvements | 36,986 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A150RadnorChesterRoadMember |  |  |
Net Improvements (Retirements) Since Acquisition | 12,549 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A150RadnorChesterRoadMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 11,897 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A150RadnorChesterRoadMember |  |  |
Buildings and Improvements | 49,563 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A150RadnorChesterRoadMember |  |  |
Total | 61,460 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A150RadnorChesterRoadMember |  |  |
Accumulated Depreciation at December 31, 2013 | 16,431 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A150RadnorChesterRoadMember |  |  |
Depreciable Life (Years) | 29 years |  |  |
One Radnor Corporate Center [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OneRadnorCorporateCenterMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 7,323 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OneRadnorCorporateCenterMember |  |  |
Buildings and Improvements | 28,613 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OneRadnorCorporateCenterMember |  |  |
Net Improvements (Retirements) Since Acquisition | 23,182 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OneRadnorCorporateCenterMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 7,323 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OneRadnorCorporateCenterMember |  |  |
Buildings and Improvements | 51,795 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OneRadnorCorporateCenterMember |  |  |
Total | 59,118 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OneRadnorCorporateCenterMember |  |  |
Accumulated Depreciation at December 31, 2013 | 18,406 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OneRadnorCorporateCenterMember |  |  |
Depreciable Life (Years) | 29 years |  |  |
201 King of Prussia Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A201KingOfPrussiaRoadMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 8,956 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A201KingOfPrussiaRoadMember |  |  |
Buildings and Improvements | 29,811 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A201KingOfPrussiaRoadMember |  |  |
Net Improvements (Retirements) Since Acquisition | 5,070 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A201KingOfPrussiaRoadMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 8,949 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A201KingOfPrussiaRoadMember |  |  |
Buildings and Improvements | 34,888 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A201KingOfPrussiaRoadMember |  |  |
Total | 43,837 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A201KingOfPrussiaRoadMember |  |  |
Accumulated Depreciation at December 31, 2013 | 15,445 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A201KingOfPrussiaRoadMember |  |  |
Depreciable Life (Years) | 25 years |  |  |
555 Lancaster Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A555LancasterAvenueMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 8,014 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A555LancasterAvenueMember |  |  |
Buildings and Improvements | 16,508 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A555LancasterAvenueMember |  |  |
Net Improvements (Retirements) Since Acquisition | 16,854 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A555LancasterAvenueMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 8,609 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A555LancasterAvenueMember |  |  |
Buildings and Improvements | 32,767 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A555LancasterAvenueMember |  |  |
Total | 41,376 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A555LancasterAvenueMember |  |  |
Accumulated Depreciation at December 31, 2013 | 12,563 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A555LancasterAvenueMember |  |  |
Depreciable Life (Years) | 24 years |  |  |
Four Radnor Corporate Center [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FourRadnorCorporateCenterMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 5,406 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FourRadnorCorporateCenterMember |  |  |
Buildings and Improvements | 21,390 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FourRadnorCorporateCenterMember |  |  |
Net Improvements (Retirements) Since Acquisition | 8,501 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FourRadnorCorporateCenterMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 5,705 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FourRadnorCorporateCenterMember |  |  |
Buildings and Improvements | 29,592 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FourRadnorCorporateCenterMember |  |  |
Total | 35,297 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FourRadnorCorporateCenterMember |  |  |
Accumulated Depreciation at December 31, 2013 | 10,480 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FourRadnorCorporateCenterMember |  |  |
Depreciable Life (Years) | 30 years |  |  |
Five Radnor Corporate Center [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FiveRadnorCorporateCenterMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 6,506 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FiveRadnorCorporateCenterMember |  |  |
Buildings and Improvements | 25,525 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FiveRadnorCorporateCenterMember |  |  |
Net Improvements (Retirements) Since Acquisition | 5,455 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FiveRadnorCorporateCenterMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 6,578 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FiveRadnorCorporateCenterMember |  |  |
Buildings and Improvements | 30,908 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FiveRadnorCorporateCenterMember |  |  |
Total | 37,486 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FiveRadnorCorporateCenterMember |  |  |
Accumulated Depreciation at December 31, 2013 | 8,024 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FiveRadnorCorporateCenterMember |  |  |
Depreciable Life (Years) | 38 years |  |  |
Three Radnor Corporate Center [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_ThreeRadnorCorporateCenterMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 4,773 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_ThreeRadnorCorporateCenterMember |  |  |
Buildings and Improvements | 17,961 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_ThreeRadnorCorporateCenterMember |  |  |
Net Improvements (Retirements) Since Acquisition | 2,645 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_ThreeRadnorCorporateCenterMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 4,791 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_ThreeRadnorCorporateCenterMember |  |  |
Buildings and Improvements | 20,588 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_ThreeRadnorCorporateCenterMember |  |  |
Total | 25,379 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_ThreeRadnorCorporateCenterMember |  |  |
Accumulated Depreciation at December 31, 2013 | 8,094 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_ThreeRadnorCorporateCenterMember |  |  |
Depreciable Life (Years) | 29 years |  |  |
Two Radnor Corporate Center [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoRadnorCorporateCenterMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 3,937 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoRadnorCorporateCenterMember |  |  |
Buildings and Improvements | 15,484 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoRadnorCorporateCenterMember |  |  |
Net Improvements (Retirements) Since Acquisition | 3,888 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoRadnorCorporateCenterMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 3,942 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoRadnorCorporateCenterMember |  |  |
Buildings and Improvements | 19,367 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoRadnorCorporateCenterMember |  |  |
Total | 23,309 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoRadnorCorporateCenterMember |  |  |
Accumulated Depreciation at December 31, 2013 | 6,882 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoRadnorCorporateCenterMember |  |  |
Depreciable Life (Years) | 29 years |  |  |
130 Radnor Chester Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A130RadnorChesterRoadMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,573 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A130RadnorChesterRoadMember |  |  |
Buildings and Improvements | 8,338 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A130RadnorChesterRoadMember |  |  |
Net Improvements (Retirements) Since Acquisition | 3,483 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A130RadnorChesterRoadMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,567 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A130RadnorChesterRoadMember |  |  |
Buildings and Improvements | 11,827 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A130RadnorChesterRoadMember |  |  |
Total | 14,394 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A130RadnorChesterRoadMember |  |  |
Accumulated Depreciation at December 31, 2013 | 4,357 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A130RadnorChesterRoadMember |  |  |
Depreciable Life (Years) | 25 years |  |  |
170 Radnor Chester Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A170RadnorChesterRoadMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,514 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A170RadnorChesterRoadMember |  |  |
Buildings and Improvements | 8,147 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A170RadnorChesterRoadMember |  |  |
Net Improvements (Retirements) Since Acquisition | 1,718 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A170RadnorChesterRoadMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,509 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A170RadnorChesterRoadMember |  |  |
Buildings and Improvements | 9,870 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A170RadnorChesterRoadMember |  |  |
Total | 12,379 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A170RadnorChesterRoadMember |  |  |
Accumulated Depreciation at December 31, 2013 | 3,051 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A170RadnorChesterRoadMember |  |  |
Depreciable Life (Years) | 25 years |  |  |
200 N. Radnor Chester Rd. [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A200N.RadnorChesterRd.Member |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 3,366 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A200N.RadnorChesterRd.Member |  |  |
Buildings and Improvements | 0 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A200N.RadnorChesterRd.Member |  |  |
Net Improvements (Retirements) Since Acquisition | 3,675 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A200N.RadnorChesterRd.Member |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 3,366 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A200N.RadnorChesterRd.Member |  |  |
Buildings and Improvements | 3,675 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A200N.RadnorChesterRd.Member |  |  |
Total | 7,041 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A200N.RadnorChesterRd.Member |  |  |
Accumulated Depreciation at December 31, 2013 | 113 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A200N.RadnorChesterRd.Member |  |  |
Depreciable Life (Years) | 40 years |  |  |
101 West Elm Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A101WestElmStreetMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 6,251 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A101WestElmStreetMember |  |  |
Buildings and Improvements | 25,209 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A101WestElmStreetMember |  |  |
Net Improvements (Retirements) Since Acquisition | 3,189 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A101WestElmStreetMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 6,251 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A101WestElmStreetMember |  |  |
Buildings and Improvements | 28,398 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A101WestElmStreetMember |  |  |
Total | 34,649 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A101WestElmStreetMember |  |  |
Accumulated Depreciation at December 31, 2013 | 7,640 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A101WestElmStreetMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
1 West Elm Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1WestElmStreetMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 3,557 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1WestElmStreetMember |  |  |
Buildings and Improvements | 14,249 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1WestElmStreetMember |  |  |
Net Improvements (Retirements) Since Acquisition | 3,876 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1WestElmStreetMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 3,557 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1WestElmStreetMember |  |  |
Buildings and Improvements | 18,125 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1WestElmStreetMember |  |  |
Total | 21,682 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1WestElmStreetMember |  |  |
Accumulated Depreciation at December 31, 2013 | 4,204 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1WestElmStreetMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
595 East Swedesford Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A595EastSwedesfordRoadMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,729 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A595EastSwedesfordRoadMember |  |  |
Buildings and Improvements | 10,917 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A595EastSwedesfordRoadMember |  |  |
Net Improvements (Retirements) Since Acquisition | 2,307 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A595EastSwedesfordRoadMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,729 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A595EastSwedesfordRoadMember |  |  |
Buildings and Improvements | 13,224 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A595EastSwedesfordRoadMember |  |  |
Total | 15,953 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A595EastSwedesfordRoadMember |  |  |
Accumulated Depreciation at December 31, 2013 | 4,464 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A595EastSwedesfordRoadMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
575 East Swedesford Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A575EastSwedesfordRoadMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,178 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A575EastSwedesfordRoadMember |  |  |
Buildings and Improvements | 8,712 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A575EastSwedesfordRoadMember |  |  |
Net Improvements (Retirements) Since Acquisition | 1,681 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A575EastSwedesfordRoadMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,178 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A575EastSwedesfordRoadMember |  |  |
Buildings and Improvements | 10,393 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A575EastSwedesfordRoadMember |  |  |
Total | 12,571 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A575EastSwedesfordRoadMember |  |  |
Accumulated Depreciation at December 31, 2013 | 3,692 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A575EastSwedesfordRoadMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
565 East Swedesford Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A565EastSwedesfordRoadMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,872 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A565EastSwedesfordRoadMember |  |  |
Buildings and Improvements | 7,489 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A565EastSwedesfordRoadMember |  |  |
Net Improvements (Retirements) Since Acquisition | 1,744 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A565EastSwedesfordRoadMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,872 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A565EastSwedesfordRoadMember |  |  |
Buildings and Improvements | 9,233 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A565EastSwedesfordRoadMember |  |  |
Total | 11,105 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A565EastSwedesfordRoadMember |  |  |
Accumulated Depreciation at December 31, 2013 | 3,166 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A565EastSwedesfordRoadMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
585 East Swedesford Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A585EastSwedesfordRoadMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,350 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A585EastSwedesfordRoadMember |  |  |
Buildings and Improvements | 5,401 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A585EastSwedesfordRoadMember |  |  |
Net Improvements (Retirements) Since Acquisition | 1,350 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A585EastSwedesfordRoadMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,350 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A585EastSwedesfordRoadMember |  |  |
Buildings and Improvements | 6,751 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A585EastSwedesfordRoadMember |  |  |
Total | 8,101 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A585EastSwedesfordRoadMember |  |  |
Accumulated Depreciation at December 31, 2013 | 1,551 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A585EastSwedesfordRoadMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
2970 Market Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 184,442 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2970MarketStreetMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 22,430 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2970MarketStreetMember |  |  |
Buildings and Improvements | 217,763 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2970MarketStreetMember |  |  |
Net Improvements (Retirements) Since Acquisition | 12,021 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2970MarketStreetMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 22,430 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2970MarketStreetMember |  |  |
Buildings and Improvements | 229,784 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2970MarketStreetMember |  |  |
Total | 252,214 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2970MarketStreetMember |  |  |
Accumulated Depreciation at December 31, 2013 | 27,560 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2970MarketStreetMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
2929 Arch Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2929ArchStreetMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 0 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2929ArchStreetMember |  |  |
Buildings and Improvements | 208,570 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2929ArchStreetMember |  |  |
Net Improvements (Retirements) Since Acquisition | 29,302 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2929ArchStreetMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 12,586 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2929ArchStreetMember |  |  |
Buildings and Improvements | 225,286 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2929ArchStreetMember |  |  |
Total | 237,872 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2929ArchStreetMember |  |  |
Accumulated Depreciation at December 31, 2013 | 85,000 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2929ArchStreetMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
1717 Arch Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1717ArchStreetMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 0 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1717ArchStreetMember |  |  |
Buildings and Improvements | 98,188 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1717ArchStreetMember |  |  |
Net Improvements (Retirements) Since Acquisition | 66,550 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1717ArchStreetMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 25,195 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1717ArchStreetMember |  |  |
Buildings and Improvements | 139,543 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1717ArchStreetMember |  |  |
Total | 164,738 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1717ArchStreetMember |  |  |
Accumulated Depreciation at December 31, 2013 | 19,000 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1717ArchStreetMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
2001 Market Street |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 112,000 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoCommerceSquareMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 15,323 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoCommerceSquareMember |  |  |
Buildings and Improvements | 120,842 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoCommerceSquareMember |  |  |
Net Improvements (Retirements) Since Acquisition | 2,125 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoCommerceSquareMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 15,323 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoCommerceSquareMember |  |  |
Buildings and Improvements | 122,967 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoCommerceSquareMember |  |  |
Total | 138,290 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoCommerceSquareMember |  |  |
Accumulated Depreciation at December 31, 2013 | 3,371 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoCommerceSquareMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
130 North 18th Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A130North18ThStreetMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 14,496 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A130North18ThStreetMember |  |  |
Buildings and Improvements | 107,736 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A130North18ThStreetMember |  |  |
Net Improvements (Retirements) Since Acquisition | 17,397 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A130North18ThStreetMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 14,473 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A130North18ThStreetMember |  |  |
Buildings and Improvements | 125,156 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A130North18ThStreetMember |  |  |
Total | 139,629 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A130North18ThStreetMember |  |  |
Accumulated Depreciation at December 31, 2013 | 37,755 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A130North18ThStreetMember |  |  |
Depreciable Life (Years) | 34 years |  |  |
100 North 18th Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 87,767 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A100North18ThStreetMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 16,066 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A100North18ThStreetMember |  |  |
Buildings and Improvements | 100,255 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A100North18ThStreetMember |  |  |
Net Improvements (Retirements) Since Acquisition | 10,925 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A100North18ThStreetMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 16,066 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A100North18ThStreetMember |  |  |
Buildings and Improvements | 111,180 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A100North18ThStreetMember |  |  |
Total | 127,246 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A100North18ThStreetMember |  |  |
Accumulated Depreciation at December 31, 2013 | 35,435 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A100North18ThStreetMember |  |  |
Depreciable Life (Years) | 36 years |  |  |
2005 Market Street |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 123,205 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OneCommerceSquareMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 15,161 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OneCommerceSquareMember |  |  |
Buildings and Improvements | 122,486 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OneCommerceSquareMember |  |  |
Net Improvements (Retirements) Since Acquisition | (11,726)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OneCommerceSquareMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 15,161 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OneCommerceSquareMember |  |  |
Buildings and Improvements | 110,760 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OneCommerceSquareMember |  |  |
Total | 125,921 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OneCommerceSquareMember |  |  |
Accumulated Depreciation at December 31, 2013 | 2,959 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OneCommerceSquareMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
2930 Chestnut Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 37,765 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2930ChestnutStreetMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 0 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2930ChestnutStreetMember |  |  |
Buildings and Improvements | 76,008 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2930ChestnutStreetMember |  |  |
Net Improvements (Retirements) Since Acquisition | 2,644 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2930ChestnutStreetMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 0 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2930ChestnutStreetMember |  |  |
Buildings and Improvements | 78,652 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2930ChestnutStreetMember |  |  |
Total | 78,652 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2930ChestnutStreetMember |  |  |
Accumulated Depreciation at December 31, 2013 | 8,677 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2930ChestnutStreetMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
1900 Market [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1900MarketMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 7,768 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1900MarketMember |  |  |
Buildings and Improvements | 17,263 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1900MarketMember |  |  |
Net Improvements (Retirements) Since Acquisition | 481 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1900MarketMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 7,768 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1900MarketMember |  |  |
Buildings and Improvements | 17,744 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1900MarketMember |  |  |
Total | 25,512 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1900MarketMember |  |  |
Accumulated Depreciation at December 31, 2013 | 1,246 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1900MarketMember |  |  |
Depreciable Life (Years) | 30 years |  |  |
3020 Market Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A3020MarketStreetMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 0 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A3020MarketStreetMember |  |  |
Buildings and Improvements | 21,417 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A3020MarketStreetMember |  |  |
Net Improvements (Retirements) Since Acquisition | 6,225 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A3020MarketStreetMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 0 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A3020MarketStreetMember |  |  |
Buildings and Improvements | 27,642 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A3020MarketStreetMember |  |  |
Total | 27,642 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A3020MarketStreetMember |  |  |
Accumulated Depreciation at December 31, 2013 | 3,260 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A3020MarketStreetMember |  |  |
Depreciable Life (Years) | 26 years |  |  |
101-103 Juniper Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A101103JuniperStreetMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 0 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A101103JuniperStreetMember |  |  |
Buildings and Improvements | 14,401 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A101103JuniperStreetMember |  |  |
Net Improvements (Retirements) Since Acquisition | 324 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A101103JuniperStreetMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 478 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A101103JuniperStreetMember |  |  |
Buildings and Improvements | 14,247 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A101103JuniperStreetMember |  |  |
Total | 14,725 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A101103JuniperStreetMember |  |  |
Accumulated Depreciation at December 31, 2013 | 1,865 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A101103JuniperStreetMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
Philadelphia Marine Center [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_PhiladelphiaMarineCenterMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 532 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_PhiladelphiaMarineCenterMember |  |  |
Buildings and Improvements | 2,196 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_PhiladelphiaMarineCenterMember |  |  |
Net Improvements (Retirements) Since Acquisition | 3,444 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_PhiladelphiaMarineCenterMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 628 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_PhiladelphiaMarineCenterMember |  |  |
Buildings and Improvements | 5,544 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_PhiladelphiaMarineCenterMember |  |  |
Total | 6,172 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_PhiladelphiaMarineCenterMember |  |  |
Accumulated Depreciation at December 31, 2013 | 2,408 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_PhiladelphiaMarineCenterMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
11720 Beltsville Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11720BeltsvilleDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 3,831 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11720BeltsvilleDriveMember |  |  |
Buildings and Improvements | 16,661 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11720BeltsvilleDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 3,399 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11720BeltsvilleDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 3,904 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11720BeltsvilleDriveMember |  |  |
Buildings and Improvements | 19,987 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11720BeltsvilleDriveMember |  |  |
Total | 23,891 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11720BeltsvilleDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 5,887 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11720BeltsvilleDriveMember |  |  |
Depreciable Life (Years) | 46 years |  |  |
11700 Beltsville Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11700BeltsvilleDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,808 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11700BeltsvilleDriveMember |  |  |
Buildings and Improvements | 12,081 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11700BeltsvilleDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 293 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11700BeltsvilleDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,863 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11700BeltsvilleDriveMember |  |  |
Buildings and Improvements | 12,319 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11700BeltsvilleDriveMember |  |  |
Total | 15,182 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11700BeltsvilleDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 2,702 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11700BeltsvilleDriveMember |  |  |
Depreciable Life (Years) | 46 years |  |  |
11710 Beltsville Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11710BeltsvilleDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,278 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11710BeltsvilleDriveMember |  |  |
Buildings and Improvements | 11,100 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11710BeltsvilleDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | (814)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11710BeltsvilleDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,321 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11710BeltsvilleDriveMember |  |  |
Buildings and Improvements | 10,243 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11710BeltsvilleDriveMember |  |  |
Total | 12,564 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11710BeltsvilleDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 2,370 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11710BeltsvilleDriveMember |  |  |
Depreciable Life (Years) | 46 years |  |  |
6600 Rockledge Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A6600RockledgeDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 0 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A6600RockledgeDriveMember |  |  |
Buildings and Improvements | 37,421 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A6600RockledgeDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 11,303 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A6600RockledgeDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 0 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A6600RockledgeDriveMember |  |  |
Buildings and Improvements | 48,724 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A6600RockledgeDriveMember |  |  |
Total | 48,724 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A6600RockledgeDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 15,070 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A6600RockledgeDriveMember |  |  |
Depreciable Life (Years) | 50 years |  |  |
11740 Beltsville Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11740BeltsvilleDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 198 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11740BeltsvilleDriveMember |  |  |
Buildings and Improvements | 870 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11740BeltsvilleDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 42 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11740BeltsvilleDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 202 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11740BeltsvilleDriveMember |  |  |
Buildings and Improvements | 908 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11740BeltsvilleDriveMember |  |  |
Total | 1,110 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11740BeltsvilleDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 211 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11740BeltsvilleDriveMember |  |  |
Depreciable Life (Years) | 46 years |  |  |
12015 Lee Jackson Memorial Highway [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A12015LeeJacksonMemorialHighwayMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 3,770 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A12015LeeJacksonMemorialHighwayMember |  |  |
Buildings and Improvements | 22,895 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A12015LeeJacksonMemorialHighwayMember |  |  |
Net Improvements (Retirements) Since Acquisition | 3,987 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A12015LeeJacksonMemorialHighwayMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 3,841 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A12015LeeJacksonMemorialHighwayMember |  |  |
Buildings and Improvements | 26,811 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A12015LeeJacksonMemorialHighwayMember |  |  |
Total | 30,652 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A12015LeeJacksonMemorialHighwayMember |  |  |
Accumulated Depreciation at December 31, 2013 | 7,188 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A12015LeeJacksonMemorialHighwayMember |  |  |
Depreciable Life (Years) | 42 years |  |  |
11781 Lee Jackson Memorial Highway [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11781LeeJacksonMemorialHighwayMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 3,246 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11781LeeJacksonMemorialHighwayMember |  |  |
Buildings and Improvements | 19,836 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11781LeeJacksonMemorialHighwayMember |  |  |
Net Improvements (Retirements) Since Acquisition | 567 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11781LeeJacksonMemorialHighwayMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 3,307 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11781LeeJacksonMemorialHighwayMember |  |  |
Buildings and Improvements | 20,342 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11781LeeJacksonMemorialHighwayMember |  |  |
Total | 23,649 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11781LeeJacksonMemorialHighwayMember |  |  |
Accumulated Depreciation at December 31, 2013 | 4,748 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A11781LeeJacksonMemorialHighwayMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
4401 Fair Lakes Court [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4401FairLakesCourtMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,569 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4401FairLakesCourtMember |  |  |
Buildings and Improvements | 11,982 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4401FairLakesCourtMember |  |  |
Net Improvements (Retirements) Since Acquisition | 247 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4401FairLakesCourtMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,599 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4401FairLakesCourtMember |  |  |
Buildings and Improvements | 12,199 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4401FairLakesCourtMember |  |  |
Total | 13,798 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4401FairLakesCourtMember |  |  |
Accumulated Depreciation at December 31, 2013 | 2,456 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4401FairLakesCourtMember |  |  |
Depreciable Life (Years) | 52 years |  |  |
3141 Fairview Park Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 21,242 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A3141FairviewParkDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 5,918 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A3141FairviewParkDriveMember |  |  |
Buildings and Improvements | 40,981 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A3141FairviewParkDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 12,017 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A3141FairviewParkDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 7,080 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A3141FairviewParkDriveMember |  |  |
Buildings and Improvements | 51,836 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A3141FairviewParkDriveMember |  |  |
Total | 58,916 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A3141FairviewParkDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 10,264 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A3141FairviewParkDriveMember |  |  |
Depreciable Life (Years) | 51 years |  |  |
2340 Dulles Corner Boulevard [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2340DullesCornerBoulevardMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 16,345 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2340DullesCornerBoulevardMember |  |  |
Buildings and Improvements | 65,379 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2340DullesCornerBoulevardMember |  |  |
Net Improvements (Retirements) Since Acquisition | 18,280 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2340DullesCornerBoulevardMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 16,129 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2340DullesCornerBoulevardMember |  |  |
Buildings and Improvements | 83,875 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2340DullesCornerBoulevardMember |  |  |
Total | 100,004 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2340DullesCornerBoulevardMember |  |  |
Accumulated Depreciation at December 31, 2013 | 28,064 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2340DullesCornerBoulevardMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
2291 Wood Oak Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2291WoodOakDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 8,243 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2291WoodOakDriveMember |  |  |
Buildings and Improvements | 52,413 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2291WoodOakDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 13,499 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2291WoodOakDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 8,782 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2291WoodOakDriveMember |  |  |
Buildings and Improvements | 65,373 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2291WoodOakDriveMember |  |  |
Total | 74,155 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2291WoodOakDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 13,524 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2291WoodOakDriveMember |  |  |
Depreciable Life (Years) | 55 years |  |  |
196/198 Van Buren Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A196198VanBurenStreetMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 7,931 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A196198VanBurenStreetMember |  |  |
Buildings and Improvements | 43,812 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A196198VanBurenStreetMember |  |  |
Net Improvements (Retirements) Since Acquisition | 9,040 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A196198VanBurenStreetMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 8,348 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A196198VanBurenStreetMember |  |  |
Buildings and Improvements | 52,435 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A196198VanBurenStreetMember |  |  |
Total | 60,783 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A196198VanBurenStreetMember |  |  |
Accumulated Depreciation at December 31, 2013 | 10,308 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A196198VanBurenStreetMember |  |  |
Depreciable Life (Years) | 53 years |  |  |
2251 Corporate Park Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2251CorporateParkDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 11,472 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2251CorporateParkDriveMember |  |  |
Buildings and Improvements | 45,893 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2251CorporateParkDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 2,276 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2251CorporateParkDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 11,472 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2251CorporateParkDriveMember |  |  |
Buildings and Improvements | 48,169 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2251CorporateParkDriveMember |  |  |
Total | 59,641 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2251CorporateParkDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 9,758 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2251CorporateParkDriveMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
2355 Dulles Corner Boulevard [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2355DullesCornerBoulevardMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 10,365 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2355DullesCornerBoulevardMember |  |  |
Buildings and Improvements | 43,876 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2355DullesCornerBoulevardMember |  |  |
Net Improvements (Retirements) Since Acquisition | 4,648 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2355DullesCornerBoulevardMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 10,365 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2355DullesCornerBoulevardMember |  |  |
Buildings and Improvements | 48,524 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2355DullesCornerBoulevardMember |  |  |
Total | 58,889 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2355DullesCornerBoulevardMember |  |  |
Accumulated Depreciation at December 31, 2013 | 12,675 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2355DullesCornerBoulevardMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
2411 Dulles Corner Park [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2411DullesCornerParkMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 7,279 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2411DullesCornerParkMember |  |  |
Buildings and Improvements | 46,340 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2411DullesCornerParkMember |  |  |
Net Improvements (Retirements) Since Acquisition | 117 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2411DullesCornerParkMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 7,417 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2411DullesCornerParkMember |  |  |
Buildings and Improvements | 46,319 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2411DullesCornerParkMember |  |  |
Total | 53,736 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2411DullesCornerParkMember |  |  |
Accumulated Depreciation at December 31, 2013 | 8,645 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2411DullesCornerParkMember |  |  |
Depreciable Life (Years) | 50 years |  |  |
13880 Dulles Corner Lane [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A13880DullesCornerLaneMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 7,236 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A13880DullesCornerLaneMember |  |  |
Buildings and Improvements | 39,213 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A13880DullesCornerLaneMember |  |  |
Net Improvements (Retirements) Since Acquisition | 3,369 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A13880DullesCornerLaneMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 7,373 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A13880DullesCornerLaneMember |  |  |
Buildings and Improvements | 42,445 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A13880DullesCornerLaneMember |  |  |
Total | 49,818 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A13880DullesCornerLaneMember |  |  |
Accumulated Depreciation at December 31, 2013 | 7,824 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A13880DullesCornerLaneMember |  |  |
Depreciable Life (Years) | 55 years |  |  |
2121 Cooperative Way [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2121CooperativeWayMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 5,598 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2121CooperativeWayMember |  |  |
Buildings and Improvements | 38,639 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2121CooperativeWayMember |  |  |
Net Improvements (Retirements) Since Acquisition | 2,532 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2121CooperativeWayMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 5,795 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2121CooperativeWayMember |  |  |
Buildings and Improvements | 40,974 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2121CooperativeWayMember |  |  |
Total | 46,769 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2121CooperativeWayMember |  |  |
Accumulated Depreciation at December 31, 2013 | 7,665 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2121CooperativeWayMember |  |  |
Depreciable Life (Years) | 54 years |  |  |
2201 Cooperative Way [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2201CooperativeWayMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 4,809 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2201CooperativeWayMember |  |  |
Buildings and Improvements | 34,093 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2201CooperativeWayMember |  |  |
Net Improvements (Retirements) Since Acquisition | 4,513 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2201CooperativeWayMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 4,809 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2201CooperativeWayMember |  |  |
Buildings and Improvements | 38,606 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2201CooperativeWayMember |  |  |
Total | 43,415 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2201CooperativeWayMember |  |  |
Accumulated Depreciation at December 31, 2013 | 7,153 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2201CooperativeWayMember |  |  |
Depreciable Life (Years) | 54 years |  |  |
13825 Sunrise Valley Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A13825SunriseValleyDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 3,794 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A13825SunriseValleyDriveMember |  |  |
Buildings and Improvements | 19,365 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A13825SunriseValleyDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 2,121 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A13825SunriseValleyDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 3,866 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A13825SunriseValleyDriveMember |  |  |
Buildings and Improvements | 21,414 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A13825SunriseValleyDriveMember |  |  |
Total | 25,280 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A13825SunriseValleyDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 4,441 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A13825SunriseValleyDriveMember |  |  |
Depreciable Life (Years) | 46 years |  |  |
1676 International Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 58,470 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1676InternationalDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 18,437 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1676InternationalDriveMember |  |  |
Buildings and Improvements | 97,538 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1676InternationalDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 3,183 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1676InternationalDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 18,785 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1676InternationalDriveMember |  |  |
Buildings and Improvements | 100,373 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1676InternationalDriveMember |  |  |
Total | 119,158 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1676InternationalDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 16,619 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1676InternationalDriveMember |  |  |
Depreciable Life (Years) | 55 years |  |  |
8260 Greensboro Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 31,043 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A8260GreensboroDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 7,952 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A8260GreensboroDriveMember |  |  |
Buildings and Improvements | 33,964 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A8260GreensboroDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 1,641 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A8260GreensboroDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 8,102 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A8260GreensboroDriveMember |  |  |
Buildings and Improvements | 35,455 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A8260GreensboroDriveMember |  |  |
Total | 43,557 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A8260GreensboroDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 7,320 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A8260GreensboroDriveMember |  |  |
Depreciable Life (Years) | 52 years |  |  |
2273 Research Boulevard [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2273ResearchBoulevardMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 5,167 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2273ResearchBoulevardMember |  |  |
Buildings and Improvements | 31,110 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2273ResearchBoulevardMember |  |  |
Net Improvements (Retirements) Since Acquisition | 3,764 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2273ResearchBoulevardMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 5,237 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2273ResearchBoulevardMember |  |  |
Buildings and Improvements | 34,804 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2273ResearchBoulevardMember |  |  |
Total | 40,041 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2273ResearchBoulevardMember |  |  |
Accumulated Depreciation at December 31, 2013 | 10,191 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2273ResearchBoulevardMember |  |  |
Depreciable Life (Years) | 45 years |  |  |
2275 Research Boulevard [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2275ResearchBoulevardMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 5,059 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2275ResearchBoulevardMember |  |  |
Buildings and Improvements | 29,668 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2275ResearchBoulevardMember |  |  |
Net Improvements (Retirements) Since Acquisition | 6,479 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2275ResearchBoulevardMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 5,154 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2275ResearchBoulevardMember |  |  |
Buildings and Improvements | 36,052 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2275ResearchBoulevardMember |  |  |
Total | 41,206 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2275ResearchBoulevardMember |  |  |
Accumulated Depreciation at December 31, 2013 | 7,672 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2275ResearchBoulevardMember |  |  |
Depreciable Life (Years) | 45 years |  |  |
2277 Research Boulevard [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2277ResearchBoulevardMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 4,649 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2277ResearchBoulevardMember |  |  |
Buildings and Improvements | 26,952 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2277ResearchBoulevardMember |  |  |
Net Improvements (Retirements) Since Acquisition | 695 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2277ResearchBoulevardMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 4,733 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2277ResearchBoulevardMember |  |  |
Buildings and Improvements | 27,563 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2277ResearchBoulevardMember |  |  |
Total | 32,296 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2277ResearchBoulevardMember |  |  |
Accumulated Depreciation at December 31, 2013 | 5,724 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2277ResearchBoulevardMember |  |  |
Depreciable Life (Years) | 45 years |  |  |
1900 Gallows Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1900GallowsRoadMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 7,797 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1900GallowsRoadMember |  |  |
Buildings and Improvements | 47,817 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1900GallowsRoadMember |  |  |
Net Improvements (Retirements) Since Acquisition | 10,849 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1900GallowsRoadMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 7,944 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1900GallowsRoadMember |  |  |
Buildings and Improvements | 58,519 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1900GallowsRoadMember |  |  |
Total | 66,463 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1900GallowsRoadMember |  |  |
Accumulated Depreciation at December 31, 2013 | 11,008 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1900GallowsRoadMember |  |  |
Depreciable Life (Years) | 52 years |  |  |
8521 Leesburg Pike [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A8521LeesburgPikeMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 4,316 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A8521LeesburgPikeMember |  |  |
Buildings and Improvements | 30,885 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A8521LeesburgPikeMember |  |  |
Net Improvements (Retirements) Since Acquisition | 4,858 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A8521LeesburgPikeMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 4,397 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A8521LeesburgPikeMember |  |  |
Buildings and Improvements | 35,662 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A8521LeesburgPikeMember |  |  |
Total | 40,059 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A8521LeesburgPikeMember |  |  |
Accumulated Depreciation at December 31, 2013 | 6,399 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A8521LeesburgPikeMember |  |  |
Depreciable Life (Years) | 51 years |  |  |
457 Haddonfield Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A457HaddonfieldRoadMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,142 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A457HaddonfieldRoadMember |  |  |
Buildings and Improvements | 9,120 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A457HaddonfieldRoadMember |  |  |
Net Improvements (Retirements) Since Acquisition | 1,402 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A457HaddonfieldRoadMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,142 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A457HaddonfieldRoadMember |  |  |
Buildings and Improvements | 10,522 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A457HaddonfieldRoadMember |  |  |
Total | 12,664 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A457HaddonfieldRoadMember |  |  |
Accumulated Depreciation at December 31, 2013 | 5,273 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A457HaddonfieldRoadMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
200 Lake Drive East [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A200LakeDriveEastMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,069 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A200LakeDriveEastMember |  |  |
Buildings and Improvements | 8,275 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A200LakeDriveEastMember |  |  |
Net Improvements (Retirements) Since Acquisition | 1,328 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A200LakeDriveEastMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,069 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A200LakeDriveEastMember |  |  |
Buildings and Improvements | 9,603 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A200LakeDriveEastMember |  |  |
Total | 11,672 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A200LakeDriveEastMember |  |  |
Accumulated Depreciation at December 31, 2013 | 3,635 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A200LakeDriveEastMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
220 Lake Drive East [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A220LakeDriveEastMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,144 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A220LakeDriveEastMember |  |  |
Buildings and Improvements | 8,798 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A220LakeDriveEastMember |  |  |
Net Improvements (Retirements) Since Acquisition | 825 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A220LakeDriveEastMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,144 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A220LakeDriveEastMember |  |  |
Buildings and Improvements | 9,623 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A220LakeDriveEastMember |  |  |
Total | 11,767 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A220LakeDriveEastMember |  |  |
Accumulated Depreciation at December 31, 2013 | 3,490 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A220LakeDriveEastMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
210 Lake Drive East [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A210LakeDriveEastMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,645 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A210LakeDriveEastMember |  |  |
Buildings and Improvements | 6,579 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A210LakeDriveEastMember |  |  |
Net Improvements (Retirements) Since Acquisition | 1,917 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A210LakeDriveEastMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,645 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A210LakeDriveEastMember |  |  |
Buildings and Improvements | 8,496 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A210LakeDriveEastMember |  |  |
Total | 10,141 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A210LakeDriveEastMember |  |  |
Accumulated Depreciation at December 31, 2013 | 2,812 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A210LakeDriveEastMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
20 East Clementon Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A20EastClementonRoadMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 769 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A20EastClementonRoadMember |  |  |
Buildings and Improvements | 3,055 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A20EastClementonRoadMember |  |  |
Net Improvements (Retirements) Since Acquisition | 480 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A20EastClementonRoadMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 769 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A20EastClementonRoadMember |  |  |
Buildings and Improvements | 3,535 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A20EastClementonRoadMember |  |  |
Total | 4,304 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A20EastClementonRoadMember |  |  |
Accumulated Depreciation at December 31, 2013 | 1,682 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A20EastClementonRoadMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
10 Foster Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A10FosterAvenueMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 244 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A10FosterAvenueMember |  |  |
Buildings and Improvements | 971 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A10FosterAvenueMember |  |  |
Net Improvements (Retirements) Since Acquisition | 78 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A10FosterAvenueMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 244 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A10FosterAvenueMember |  |  |
Buildings and Improvements | 1,049 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A10FosterAvenueMember |  |  |
Total | 1,293 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A10FosterAvenueMember |  |  |
Accumulated Depreciation at December 31, 2013 | 497 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A10FosterAvenueMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
7 Foster Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7FosterAvenueMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 231 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7FosterAvenueMember |  |  |
Buildings and Improvements | 921 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7FosterAvenueMember |  |  |
Net Improvements (Retirements) Since Acquisition | 123 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7FosterAvenueMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 231 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7FosterAvenueMember |  |  |
Buildings and Improvements | 1,044 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7FosterAvenueMember |  |  |
Total | 1,275 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7FosterAvenueMember |  |  |
Accumulated Depreciation at December 31, 2013 | 475 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7FosterAvenueMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
50 East Clementon Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A50EastClementonRoadMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 114 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A50EastClementonRoadMember |  |  |
Buildings and Improvements | 964 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A50EastClementonRoadMember |  |  |
Net Improvements (Retirements) Since Acquisition | 653 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A50EastClementonRoadMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 114 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A50EastClementonRoadMember |  |  |
Buildings and Improvements | 1,617 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A50EastClementonRoadMember |  |  |
Total | 1,731 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A50EastClementonRoadMember |  |  |
Accumulated Depreciation at December 31, 2013 | 483 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A50EastClementonRoadMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
2 Foster Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2FosterAvenueMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 185 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2FosterAvenueMember |  |  |
Buildings and Improvements | 730 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2FosterAvenueMember |  |  |
Net Improvements (Retirements) Since Acquisition | 16 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2FosterAvenueMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 185 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2FosterAvenueMember |  |  |
Buildings and Improvements | 746 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2FosterAvenueMember |  |  |
Total | 931 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2FosterAvenueMember |  |  |
Accumulated Depreciation at December 31, 2013 | 351 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2FosterAvenueMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
4 Foster Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4FosterAvenueMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 183 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4FosterAvenueMember |  |  |
Buildings and Improvements | 726 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4FosterAvenueMember |  |  |
Net Improvements (Retirements) Since Acquisition | 16 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4FosterAvenueMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 183 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4FosterAvenueMember |  |  |
Buildings and Improvements | 742 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4FosterAvenueMember |  |  |
Total | 925 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4FosterAvenueMember |  |  |
Accumulated Depreciation at December 31, 2013 | 343 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4FosterAvenueMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
1 Foster Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1FosterAvenueMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 93 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1FosterAvenueMember |  |  |
Buildings and Improvements | 364 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1FosterAvenueMember |  |  |
Net Improvements (Retirements) Since Acquisition | 57 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1FosterAvenueMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 93 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1FosterAvenueMember |  |  |
Buildings and Improvements | 421 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1FosterAvenueMember |  |  |
Total | 514 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1FosterAvenueMember |  |  |
Accumulated Depreciation at December 31, 2013 | 215 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1FosterAvenueMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
5 U.S. Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A5USAvenueMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 21 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A5USAvenueMember |  |  |
Buildings and Improvements | 81 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A5USAvenueMember |  |  |
Net Improvements (Retirements) Since Acquisition | 3 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A5USAvenueMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 21 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A5USAvenueMember |  |  |
Buildings and Improvements | 84 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A5USAvenueMember |  |  |
Total | 105 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A5USAvenueMember |  |  |
Accumulated Depreciation at December 31, 2013 | 39 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A5USAvenueMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
5 Foster Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A5FosterAvenueMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 9 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A5FosterAvenueMember |  |  |
Buildings and Improvements | 32 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A5FosterAvenueMember |  |  |
Net Improvements (Retirements) Since Acquisition | 26 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A5FosterAvenueMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 9 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A5FosterAvenueMember |  |  |
Buildings and Improvements | 58 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A5FosterAvenueMember |  |  |
Total | 67 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A5FosterAvenueMember |  |  |
Accumulated Depreciation at December 31, 2013 | 28 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A5FosterAvenueMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
1120 Executive Boulevard [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1120ExecutiveBoulevardMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,074 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1120ExecutiveBoulevardMember |  |  |
Buildings and Improvements | 8,415 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1120ExecutiveBoulevardMember |  |  |
Net Improvements (Retirements) Since Acquisition | 4,398 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1120ExecutiveBoulevardMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,074 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1120ExecutiveBoulevardMember |  |  |
Buildings and Improvements | 12,813 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1120ExecutiveBoulevardMember |  |  |
Total | 14,887 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1120ExecutiveBoulevardMember |  |  |
Accumulated Depreciation at December 31, 2013 | 5,143 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1120ExecutiveBoulevardMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
Two Eves Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoEvesDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 818 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoEvesDriveMember |  |  |
Buildings and Improvements | 3,461 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoEvesDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 234 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoEvesDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 818 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoEvesDriveMember |  |  |
Buildings and Improvements | 3,695 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoEvesDriveMember |  |  |
Total | 4,513 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoEvesDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 1,825 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoEvesDriveMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
Five Eves Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FiveEvesDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 703 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FiveEvesDriveMember |  |  |
Buildings and Improvements | 2,819 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FiveEvesDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 665 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FiveEvesDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 703 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FiveEvesDriveMember |  |  |
Buildings and Improvements | 3,484 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FiveEvesDriveMember |  |  |
Total | 4,187 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FiveEvesDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 1,643 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FiveEvesDriveMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
Four B Eves Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FourBEvesDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 588 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FourBEvesDriveMember |  |  |
Buildings and Improvements | 2,369 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FourBEvesDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 420 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FourBEvesDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 588 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FourBEvesDriveMember |  |  |
Buildings and Improvements | 2,789 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FourBEvesDriveMember |  |  |
Total | 3,377 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FourBEvesDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 1,449 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FourBEvesDriveMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
Four A Eves Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FourEvesDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 539 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FourEvesDriveMember |  |  |
Buildings and Improvements | 2,168 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FourEvesDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 322 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FourEvesDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 539 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FourEvesDriveMember |  |  |
Buildings and Improvements | 2,490 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FourEvesDriveMember |  |  |
Total | 3,029 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FourEvesDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 1,122 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_FourEvesDriveMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
308 Harper Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A308HarperDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,643 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A308HarperDriveMember |  |  |
Buildings and Improvements | 6,663 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A308HarperDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 739 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A308HarperDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,643 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A308HarperDriveMember |  |  |
Buildings and Improvements | 7,402 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A308HarperDriveMember |  |  |
Total | 9,045 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A308HarperDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 3,258 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A308HarperDriveMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
10000 Midlantic Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A10000MidlanticDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 3,206 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A10000MidlanticDriveMember |  |  |
Buildings and Improvements | 12,857 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A10000MidlanticDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 4,228 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A10000MidlanticDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 3,206 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A10000MidlanticDriveMember |  |  |
Buildings and Improvements | 17,085 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A10000MidlanticDriveMember |  |  |
Total | 20,291 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A10000MidlanticDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 7,138 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A10000MidlanticDriveMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
700 East Gate Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A700EastGateDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 3,569 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A700EastGateDriveMember |  |  |
Buildings and Improvements | 14,436 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A700EastGateDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 2,243 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A700EastGateDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 3,569 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A700EastGateDriveMember |  |  |
Buildings and Improvements | 16,679 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A700EastGateDriveMember |  |  |
Total | 20,248 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A700EastGateDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 7,576 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A700EastGateDriveMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
15000 Midlantic Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A15000MidlanticDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 3,061 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A15000MidlanticDriveMember |  |  |
Buildings and Improvements | 12,254 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A15000MidlanticDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 1,619 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A15000MidlanticDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 3,061 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A15000MidlanticDriveMember |  |  |
Buildings and Improvements | 13,873 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A15000MidlanticDriveMember |  |  |
Total | 16,934 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A15000MidlanticDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 6,518 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A15000MidlanticDriveMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
1000 Howard Boulevard [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1000HowardBoulevardMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,297 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1000HowardBoulevardMember |  |  |
Buildings and Improvements | 9,288 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1000HowardBoulevardMember |  |  |
Net Improvements (Retirements) Since Acquisition | 3,922 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1000HowardBoulevardMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,297 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1000HowardBoulevardMember |  |  |
Buildings and Improvements | 13,210 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1000HowardBoulevardMember |  |  |
Total | 15,507 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1000HowardBoulevardMember |  |  |
Accumulated Depreciation at December 31, 2013 | 5,900 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1000HowardBoulevardMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
1000 Atrium Way [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1000AtriumWayMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,061 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1000AtriumWayMember |  |  |
Buildings and Improvements | 8,180 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1000AtriumWayMember |  |  |
Net Improvements (Retirements) Since Acquisition | 4,531 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1000AtriumWayMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,061 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1000AtriumWayMember |  |  |
Buildings and Improvements | 12,711 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1000AtriumWayMember |  |  |
Total | 14,772 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1000AtriumWayMember |  |  |
Accumulated Depreciation at December 31, 2013 | 5,894 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1000AtriumWayMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
2000 Midlantic Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2000MidlanticDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,202 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2000MidlanticDriveMember |  |  |
Buildings and Improvements | 8,823 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2000MidlanticDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 2,970 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2000MidlanticDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,202 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2000MidlanticDriveMember |  |  |
Buildings and Improvements | 11,793 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2000MidlanticDriveMember |  |  |
Total | 13,995 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2000MidlanticDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 5,349 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2000MidlanticDriveMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
701 East Gate Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A701EastGateDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,736 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A701EastGateDriveMember |  |  |
Buildings and Improvements | 6,877 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A701EastGateDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 1,768 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A701EastGateDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,736 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A701EastGateDriveMember |  |  |
Buildings and Improvements | 8,645 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A701EastGateDriveMember |  |  |
Total | 10,381 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A701EastGateDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 3,715 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A701EastGateDriveMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
9000 Midlantic Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9000MidlanticDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,472 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9000MidlanticDriveMember |  |  |
Buildings and Improvements | 5,895 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9000MidlanticDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 2,185 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9000MidlanticDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,472 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9000MidlanticDriveMember |  |  |
Buildings and Improvements | 8,080 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9000MidlanticDriveMember |  |  |
Total | 9,552 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9000MidlanticDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 3,503 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9000MidlanticDriveMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
307 Fellowship Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A307FellowshipDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,565 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A307FellowshipDriveMember |  |  |
Buildings and Improvements | 6,342 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A307FellowshipDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 1,517 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A307FellowshipDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,565 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A307FellowshipDriveMember |  |  |
Buildings and Improvements | 7,859 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A307FellowshipDriveMember |  |  |
Total | 9,424 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A307FellowshipDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 3,472 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A307FellowshipDriveMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
305 Fellowship Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A305FellowshipDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,421 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A305FellowshipDriveMember |  |  |
Buildings and Improvements | 5,768 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A305FellowshipDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 1,631 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A305FellowshipDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,421 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A305FellowshipDriveMember |  |  |
Buildings and Improvements | 7,399 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A305FellowshipDriveMember |  |  |
Total | 8,820 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A305FellowshipDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 3,122 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A305FellowshipDriveMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
303 Fellowship Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A303FellowshipDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,493 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A303FellowshipDriveMember |  |  |
Buildings and Improvements | 6,055 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A303FellowshipDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 851 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A303FellowshipDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,493 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A303FellowshipDriveMember |  |  |
Buildings and Improvements | 6,906 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A303FellowshipDriveMember |  |  |
Total | 8,399 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A303FellowshipDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 3,114 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A303FellowshipDriveMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
309 Fellowship Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A309FellowshipDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,518 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A309FellowshipDriveMember |  |  |
Buildings and Improvements | 6,154 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A309FellowshipDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 780 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A309FellowshipDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,518 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A309FellowshipDriveMember |  |  |
Buildings and Improvements | 6,934 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A309FellowshipDriveMember |  |  |
Total | 8,452 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A309FellowshipDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 3,070 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A309FellowshipDriveMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
1000 Bishops Gate [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1000BishopsGateMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 934 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1000BishopsGateMember |  |  |
Buildings and Improvements | 6,287 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1000BishopsGateMember |  |  |
Net Improvements (Retirements) Since Acquisition | (647)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1000BishopsGateMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 934 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1000BishopsGateMember |  |  |
Buildings and Improvements | 5,640 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1000BishopsGateMember |  |  |
Total | 6,574 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1000BishopsGateMember |  |  |
Accumulated Depreciation at December 31, 2013 | 1,534 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1000BishopsGateMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
161 Gaither Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A161GaitherDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,016 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A161GaitherDriveMember |  |  |
Buildings and Improvements | 4,064 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A161GaitherDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 731 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A161GaitherDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,016 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A161GaitherDriveMember |  |  |
Buildings and Improvements | 4,795 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A161GaitherDriveMember |  |  |
Total | 5,811 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A161GaitherDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 1,855 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A161GaitherDriveMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
815 East Gate Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A815EastGateDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 636 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A815EastGateDriveMember |  |  |
Buildings and Improvements | 2,584 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A815EastGateDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 550 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A815EastGateDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 636 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A815EastGateDriveMember |  |  |
Buildings and Improvements | 3,134 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A815EastGateDriveMember |  |  |
Total | 3,770 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A815EastGateDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 1,436 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A815EastGateDriveMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
4000 Midlantic Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4000MidlanticDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 714 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4000MidlanticDriveMember |  |  |
Buildings and Improvements | 5,085 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4000MidlanticDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | (1,833)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4000MidlanticDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 714 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4000MidlanticDriveMember |  |  |
Buildings and Improvements | 3,252 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4000MidlanticDriveMember |  |  |
Total | 3,966 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4000MidlanticDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 1,531 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4000MidlanticDriveMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
817 East Gate Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A817EastGateDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 611 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A817EastGateDriveMember |  |  |
Buildings and Improvements | 2,426 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A817EastGateDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 263 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A817EastGateDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 611 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A817EastGateDriveMember |  |  |
Buildings and Improvements | 2,689 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A817EastGateDriveMember |  |  |
Total | 3,300 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A817EastGateDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 1,159 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A817EastGateDriveMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
400 Commerce Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A400CommerceDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,528 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A400CommerceDriveMember |  |  |
Buildings and Improvements | 9,220 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A400CommerceDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 1,086 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A400CommerceDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,528 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A400CommerceDriveMember |  |  |
Buildings and Improvements | 10,306 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A400CommerceDriveMember |  |  |
Total | 12,834 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A400CommerceDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 3,911 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A400CommerceDriveMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
100 Commerce Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A100CommerceDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,160 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A100CommerceDriveMember |  |  |
Buildings and Improvements | 4,633 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A100CommerceDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 859 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A100CommerceDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,160 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A100CommerceDriveMember |  |  |
Buildings and Improvements | 5,492 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A100CommerceDriveMember |  |  |
Total | 6,652 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A100CommerceDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 2,595 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A100CommerceDriveMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
200 Commerce Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A200CommerceDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 911 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A200CommerceDriveMember |  |  |
Buildings and Improvements | 4,414 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A200CommerceDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 1,018 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A200CommerceDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 911 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A200CommerceDriveMember |  |  |
Buildings and Improvements | 5,432 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A200CommerceDriveMember |  |  |
Total | 6,343 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A200CommerceDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 2,180 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A200CommerceDriveMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
Main Street-Plaza 1000 [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_MainStreetPlaza1000Member |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,732 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_MainStreetPlaza1000Member |  |  |
Buildings and Improvements | 10,942 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_MainStreetPlaza1000Member |  |  |
Net Improvements (Retirements) Since Acquisition | 2,933 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_MainStreetPlaza1000Member |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,732 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_MainStreetPlaza1000Member |  |  |
Buildings and Improvements | 13,875 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_MainStreetPlaza1000Member |  |  |
Total | 16,607 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_MainStreetPlaza1000Member |  |  |
Accumulated Depreciation at December 31, 2013 | 13,211 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_MainStreetPlaza1000Member |  |  |
Depreciable Life (Years) | 40 years |  |  |
Main Street-Piazza [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_MainStreetPiazzaMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 696 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_MainStreetPiazzaMember |  |  |
Buildings and Improvements | 2,802 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_MainStreetPiazzaMember |  |  |
Net Improvements (Retirements) Since Acquisition | 3,034 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_MainStreetPiazzaMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 696 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_MainStreetPiazzaMember |  |  |
Buildings and Improvements | 5,836 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_MainStreetPiazzaMember |  |  |
Total | 6,532 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_MainStreetPiazzaMember |  |  |
Accumulated Depreciation at December 31, 2013 | 1,714 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_MainStreetPiazzaMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
Main Street-Promenade [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_MainStreetPromenadeMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 531 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_MainStreetPromenadeMember |  |  |
Buildings and Improvements | 2,052 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_MainStreetPromenadeMember |  |  |
Net Improvements (Retirements) Since Acquisition | 444 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_MainStreetPromenadeMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 531 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_MainStreetPromenadeMember |  |  |
Buildings and Improvements | 2,496 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_MainStreetPromenadeMember |  |  |
Total | 3,027 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_MainStreetPromenadeMember |  |  |
Accumulated Depreciation at December 31, 2013 | 1,218 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_MainStreetPromenadeMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
920 North King Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A920NorthKingStreetMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 6,141 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A920NorthKingStreetMember |  |  |
Buildings and Improvements | 21,140 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A920NorthKingStreetMember |  |  |
Net Improvements (Retirements) Since Acquisition | 2,669 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A920NorthKingStreetMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 6,141 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A920NorthKingStreetMember |  |  |
Buildings and Improvements | 23,809 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A920NorthKingStreetMember |  |  |
Total | 29,950 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A920NorthKingStreetMember |  |  |
Accumulated Depreciation at December 31, 2013 | 7,669 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A920NorthKingStreetMember |  |  |
Depreciable Life (Years) | 30 years |  |  |
300 Delaware Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A300DelawareAvenueMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 6,368 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A300DelawareAvenueMember |  |  |
Buildings and Improvements | 13,739 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A300DelawareAvenueMember |  |  |
Net Improvements (Retirements) Since Acquisition | 2,548 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A300DelawareAvenueMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 6,368 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A300DelawareAvenueMember |  |  |
Buildings and Improvements | 16,287 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A300DelawareAvenueMember |  |  |
Total | 22,655 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A300DelawareAvenueMember |  |  |
Accumulated Depreciation at December 31, 2013 | 6,642 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A300DelawareAvenueMember |  |  |
Depreciable Life (Years) | 23 years |  |  |
Two Righter Parkway [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoRighterParkwayMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,802 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoRighterParkwayMember |  |  |
Buildings and Improvements | 11,217 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoRighterParkwayMember |  |  |
Net Improvements (Retirements) Since Acquisition | 6,172 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoRighterParkwayMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,802 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoRighterParkwayMember |  |  |
Buildings and Improvements | 17,389 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoRighterParkwayMember |  |  |
Total | 20,191 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoRighterParkwayMember |  |  |
Accumulated Depreciation at December 31, 2013 | 4,822 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoRighterParkwayMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
One Righter Parkway [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OneRighterParkwayMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,545 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OneRighterParkwayMember |  |  |
Buildings and Improvements | 10,195 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OneRighterParkwayMember |  |  |
Net Improvements (Retirements) Since Acquisition | 5,864 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OneRighterParkwayMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,545 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OneRighterParkwayMember |  |  |
Buildings and Improvements | 16,059 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OneRighterParkwayMember |  |  |
Total | 18,604 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OneRighterParkwayMember |  |  |
Accumulated Depreciation at December 31, 2013 | 8,839 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OneRighterParkwayMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
4364 South Alston Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4364SouthAlstonAvenueMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,622 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4364SouthAlstonAvenueMember |  |  |
Buildings and Improvements | 6,419 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4364SouthAlstonAvenueMember |  |  |
Net Improvements (Retirements) Since Acquisition | 1,357 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4364SouthAlstonAvenueMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,581 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4364SouthAlstonAvenueMember |  |  |
Buildings and Improvements | 7,817 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4364SouthAlstonAvenueMember |  |  |
Total | 9,398 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4364SouthAlstonAvenueMember |  |  |
Accumulated Depreciation at December 31, 2013 | 3,174 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4364SouthAlstonAvenueMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
4805 Lake Brooke Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4805LakeBrookeDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,640 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4805LakeBrookeDriveMember |  |  |
Buildings and Improvements | 6,567 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4805LakeBrookeDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 1,537 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4805LakeBrookeDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,640 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4805LakeBrookeDriveMember |  |  |
Buildings and Improvements | 8,104 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4805LakeBrookeDriveMember |  |  |
Total | 9,744 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4805LakeBrookeDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 3,243 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A4805LakeBrookeDriveMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
Overlook I [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OverlookIMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 748 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OverlookIMember |  |  |
Buildings and Improvements | 3,976 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OverlookIMember |  |  |
Net Improvements (Retirements) Since Acquisition | 599 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OverlookIMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 790 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OverlookIMember |  |  |
Buildings and Improvements | 4,533 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OverlookIMember |  |  |
Total | 5,323 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OverlookIMember |  |  |
Accumulated Depreciation at December 31, 2013 | 677 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OverlookIMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
Overlook II [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OverlookIiMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 748 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OverlookIiMember |  |  |
Buildings and Improvements | 4,492 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OverlookIiMember |  |  |
Net Improvements (Retirements) Since Acquisition | 364 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OverlookIiMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 790 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OverlookIiMember |  |  |
Buildings and Improvements | 4,814 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OverlookIiMember |  |  |
Total | 5,604 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OverlookIiMember |  |  |
Accumulated Depreciation at December 31, 2013 | 671 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OverlookIiMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
2812 Emerywood Parkway [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2812EmerywoodParkwayMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,069 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2812EmerywoodParkwayMember |  |  |
Buildings and Improvements | 4,281 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2812EmerywoodParkwayMember |  |  |
Net Improvements (Retirements) Since Acquisition | 515 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2812EmerywoodParkwayMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,069 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2812EmerywoodParkwayMember |  |  |
Buildings and Improvements | 4,796 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2812EmerywoodParkwayMember |  |  |
Total | 5,865 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2812EmerywoodParkwayMember |  |  |
Accumulated Depreciation at December 31, 2013 | 2,182 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2812EmerywoodParkwayMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
300 Arboretum Place [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A300ArboretumPlaceMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 5,450 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A300ArboretumPlaceMember |  |  |
Buildings and Improvements | 21,892 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A300ArboretumPlaceMember |  |  |
Net Improvements (Retirements) Since Acquisition | 6,917 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A300ArboretumPlaceMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 5,450 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A300ArboretumPlaceMember |  |  |
Buildings and Improvements | 28,809 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A300ArboretumPlaceMember |  |  |
Total | 34,259 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A300ArboretumPlaceMember |  |  |
Accumulated Depreciation at December 31, 2013 | 10,862 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A300ArboretumPlaceMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
7501 Boulders View Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7501BouldersViewDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 4,669 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7501BouldersViewDriveMember |  |  |
Buildings and Improvements | 19,699 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7501BouldersViewDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 2,071 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7501BouldersViewDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 4,925 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7501BouldersViewDriveMember |  |  |
Buildings and Improvements | 21,514 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7501BouldersViewDriveMember |  |  |
Total | 26,439 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7501BouldersViewDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 4,786 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7501BouldersViewDriveMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
7300 Beaufont Springs Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7300BeaufontSpringsDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 4,672 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7300BeaufontSpringsDriveMember |  |  |
Buildings and Improvements | 19,689 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7300BeaufontSpringsDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 2,857 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7300BeaufontSpringsDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 4,922 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7300BeaufontSpringsDriveMember |  |  |
Buildings and Improvements | 22,296 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7300BeaufontSpringsDriveMember |  |  |
Total | 27,218 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7300BeaufontSpringsDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 4,223 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7300BeaufontSpringsDriveMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
6800 Paragon Place [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A6800ParagonPlaceMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 4,552 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A6800ParagonPlaceMember |  |  |
Buildings and Improvements | 18,414 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A6800ParagonPlaceMember |  |  |
Net Improvements (Retirements) Since Acquisition | 2,163 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A6800ParagonPlaceMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 4,552 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A6800ParagonPlaceMember |  |  |
Buildings and Improvements | 20,577 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A6800ParagonPlaceMember |  |  |
Total | 25,129 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A6800ParagonPlaceMember |  |  |
Accumulated Depreciation at December 31, 2013 | 4,651 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A6800ParagonPlaceMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
6802 Paragon Place [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A6802ParagonPlaceMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,917 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A6802ParagonPlaceMember |  |  |
Buildings and Improvements | 11,454 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A6802ParagonPlaceMember |  |  |
Net Improvements (Retirements) Since Acquisition | 3,143 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A6802ParagonPlaceMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,917 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A6802ParagonPlaceMember |  |  |
Buildings and Improvements | 14,597 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A6802ParagonPlaceMember |  |  |
Total | 17,514 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A6802ParagonPlaceMember |  |  |
Accumulated Depreciation at December 31, 2013 | 5,312 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A6802ParagonPlaceMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
1025 Boulders Parkway [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1025BouldersParkwayMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,574 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1025BouldersParkwayMember |  |  |
Buildings and Improvements | 11,297 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1025BouldersParkwayMember |  |  |
Net Improvements (Retirements) Since Acquisition | 1,704 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1025BouldersParkwayMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,824 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1025BouldersParkwayMember |  |  |
Buildings and Improvements | 12,751 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1025BouldersParkwayMember |  |  |
Total | 15,575 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1025BouldersParkwayMember |  |  |
Accumulated Depreciation at December 31, 2013 | 2,545 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1025BouldersParkwayMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
2100-2116 West Laburnam Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A21002116WestLaburnamAvenueMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,482 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A21002116WestLaburnamAvenueMember |  |  |
Buildings and Improvements | 8,846 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A21002116WestLaburnamAvenueMember |  |  |
Net Improvements (Retirements) Since Acquisition | 2,770 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A21002116WestLaburnamAvenueMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,482 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A21002116WestLaburnamAvenueMember |  |  |
Buildings and Improvements | 11,616 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A21002116WestLaburnamAvenueMember |  |  |
Total | 14,098 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A21002116WestLaburnamAvenueMember |  |  |
Accumulated Depreciation at December 31, 2013 | 5,162 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A21002116WestLaburnamAvenueMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
7401 Beaufont Springs Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7401BeaufontSpringsDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,349 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7401BeaufontSpringsDriveMember |  |  |
Buildings and Improvements | 10,396 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7401BeaufontSpringsDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 1,011 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7401BeaufontSpringsDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,599 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7401BeaufontSpringsDriveMember |  |  |
Buildings and Improvements | 11,157 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7401BeaufontSpringsDriveMember |  |  |
Total | 13,756 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7401BeaufontSpringsDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 2,289 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7401BeaufontSpringsDriveMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
7325 Beaufont Springs Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7325BeaufontSpringsDriveMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,344 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7325BeaufontSpringsDriveMember |  |  |
Buildings and Improvements | 10,377 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7325BeaufontSpringsDriveMember |  |  |
Net Improvements (Retirements) Since Acquisition | 630 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7325BeaufontSpringsDriveMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,594 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7325BeaufontSpringsDriveMember |  |  |
Buildings and Improvements | 10,757 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7325BeaufontSpringsDriveMember |  |  |
Total | 13,351 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7325BeaufontSpringsDriveMember |  |  |
Accumulated Depreciation at December 31, 2013 | 2,049 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A7325BeaufontSpringsDriveMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
9011 Arboretum Parkway [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9011ArboretumParkwayMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,857 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9011ArboretumParkwayMember |  |  |
Buildings and Improvements | 7,702 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9011ArboretumParkwayMember |  |  |
Net Improvements (Retirements) Since Acquisition | 940 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9011ArboretumParkwayMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,857 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9011ArboretumParkwayMember |  |  |
Buildings and Improvements | 8,642 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9011ArboretumParkwayMember |  |  |
Total | 10,499 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9011ArboretumParkwayMember |  |  |
Accumulated Depreciation at December 31, 2013 | 3,854 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9011ArboretumParkwayMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
6806 Paragon Place [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A6806ParagonPlaceMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 0 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A6806ParagonPlaceMember |  |  |
Buildings and Improvements | 10,288 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A6806ParagonPlaceMember |  |  |
Net Improvements (Retirements) Since Acquisition | (37)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A6806ParagonPlaceMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 402 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A6806ParagonPlaceMember |  |  |
Buildings and Improvements | 9,849 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A6806ParagonPlaceMember |  |  |
Total | 10,251 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A6806ParagonPlaceMember |  |  |
Accumulated Depreciation at December 31, 2013 | 2,660 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A6806ParagonPlaceMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
9100 Arboretum Parkway [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9100ArboretumParkwayMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,362 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9100ArboretumParkwayMember |  |  |
Buildings and Improvements | 5,489 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9100ArboretumParkwayMember |  |  |
Net Improvements (Retirements) Since Acquisition | 979 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9100ArboretumParkwayMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,362 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9100ArboretumParkwayMember |  |  |
Buildings and Improvements | 6,468 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9100ArboretumParkwayMember |  |  |
Total | 7,830 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9100ArboretumParkwayMember |  |  |
Accumulated Depreciation at December 31, 2013 | 2,807 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9100ArboretumParkwayMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
2511 Brittons Hill Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2511BrittonsHillRoadMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,202 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2511BrittonsHillRoadMember |  |  |
Buildings and Improvements | 4,820 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2511BrittonsHillRoadMember |  |  |
Net Improvements (Retirements) Since Acquisition | 1,221 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2511BrittonsHillRoadMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,202 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2511BrittonsHillRoadMember |  |  |
Buildings and Improvements | 6,041 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2511BrittonsHillRoadMember |  |  |
Total | 7,243 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2511BrittonsHillRoadMember |  |  |
Accumulated Depreciation at December 31, 2013 | 2,846 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2511BrittonsHillRoadMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
100 Gateway Centre Parkway [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A100GatewayCentreParkwayMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 391 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A100GatewayCentreParkwayMember |  |  |
Buildings and Improvements | 5,410 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A100GatewayCentreParkwayMember |  |  |
Net Improvements (Retirements) Since Acquisition | 617 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A100GatewayCentreParkwayMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 391 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A100GatewayCentreParkwayMember |  |  |
Buildings and Improvements | 6,027 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A100GatewayCentreParkwayMember |  |  |
Total | 6,418 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A100GatewayCentreParkwayMember |  |  |
Accumulated Depreciation at December 31, 2013 | 1,922 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A100GatewayCentreParkwayMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
9200 Arboretum Parkway [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9200ArboretumParkwayMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 985 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9200ArboretumParkwayMember |  |  |
Buildings and Improvements | 3,973 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9200ArboretumParkwayMember |  |  |
Net Improvements (Retirements) Since Acquisition | 1,252 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9200ArboretumParkwayMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 985 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9200ArboretumParkwayMember |  |  |
Buildings and Improvements | 5,225 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9200ArboretumParkwayMember |  |  |
Total | 6,210 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9200ArboretumParkwayMember |  |  |
Accumulated Depreciation at December 31, 2013 | 2,348 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9200ArboretumParkwayMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
9210 Arboretum Parkway [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9210ArboretumParkwayMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,110 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9210ArboretumParkwayMember |  |  |
Buildings and Improvements | 4,474 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9210ArboretumParkwayMember |  |  |
Net Improvements (Retirements) Since Acquisition | 517 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9210ArboretumParkwayMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,110 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9210ArboretumParkwayMember |  |  |
Buildings and Improvements | 4,991 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9210ArboretumParkwayMember |  |  |
Total | 6,101 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9210ArboretumParkwayMember |  |  |
Accumulated Depreciation at December 31, 2013 | 2,239 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9210ArboretumParkwayMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
2201-2245 Tomlynn Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A22012245TomlynnStreetMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,020 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A22012245TomlynnStreetMember |  |  |
Buildings and Improvements | 4,067 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A22012245TomlynnStreetMember |  |  |
Net Improvements (Retirements) Since Acquisition | 1,046 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A22012245TomlynnStreetMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,020 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A22012245TomlynnStreetMember |  |  |
Buildings and Improvements | 5,113 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A22012245TomlynnStreetMember |  |  |
Total | 6,133 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A22012245TomlynnStreetMember |  |  |
Accumulated Depreciation at December 31, 2013 | 2,154 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A22012245TomlynnStreetMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
9211 Arboretum Parkway [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9211ArboretumParkwayMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 582 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9211ArboretumParkwayMember |  |  |
Buildings and Improvements | 2,433 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9211ArboretumParkwayMember |  |  |
Net Improvements (Retirements) Since Acquisition | 844 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9211ArboretumParkwayMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 582 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9211ArboretumParkwayMember |  |  |
Buildings and Improvements | 3,277 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9211ArboretumParkwayMember |  |  |
Total | 3,859 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9211ArboretumParkwayMember |  |  |
Accumulated Depreciation at December 31, 2013 | 1,317 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A9211ArboretumParkwayMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
2221-2245 Dabney Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A22212245DabneyRoadMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 530 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A22212245DabneyRoadMember |  |  |
Buildings and Improvements | 2,123 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A22212245DabneyRoadMember |  |  |
Net Improvements (Retirements) Since Acquisition | 359 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A22212245DabneyRoadMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 530 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A22212245DabneyRoadMember |  |  |
Buildings and Improvements | 2,482 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A22212245DabneyRoadMember |  |  |
Total | 3,012 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A22212245DabneyRoadMember |  |  |
Accumulated Depreciation at December 31, 2013 | 990 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A22212245DabneyRoadMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
2212-2224 Tomlynn Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A22122224TomlynnStreetMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 502 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A22122224TomlynnStreetMember |  |  |
Buildings and Improvements | 2,014 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A22122224TomlynnStreetMember |  |  |
Net Improvements (Retirements) Since Acquisition | 395 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A22122224TomlynnStreetMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 502 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A22122224TomlynnStreetMember |  |  |
Buildings and Improvements | 2,409 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A22122224TomlynnStreetMember |  |  |
Total | 2,911 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A22122224TomlynnStreetMember |  |  |
Accumulated Depreciation at December 31, 2013 | 1,020 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A22122224TomlynnStreetMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
2244 Dabney Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2244DabneyRoadMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 550 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2244DabneyRoadMember |  |  |
Buildings and Improvements | 2,203 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2244DabneyRoadMember |  |  |
Net Improvements (Retirements) Since Acquisition | 0 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2244DabneyRoadMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 550 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2244DabneyRoadMember |  |  |
Buildings and Improvements | 2,203 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2244DabneyRoadMember |  |  |
Total | 2,753 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2244DabneyRoadMember |  |  |
Accumulated Depreciation at December 31, 2013 | 964 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2244DabneyRoadMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
2277 Dabney Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2277DabneyRoadMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 507 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2277DabneyRoadMember |  |  |
Buildings and Improvements | 2,034 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2277DabneyRoadMember |  |  |
Net Improvements (Retirements) Since Acquisition | 294 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2277DabneyRoadMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 507 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2277DabneyRoadMember |  |  |
Buildings and Improvements | 2,328 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2277DabneyRoadMember |  |  |
Total | 2,835 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2277DabneyRoadMember |  |  |
Accumulated Depreciation at December 31, 2013 | 977 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2277DabneyRoadMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
2248 Dabney Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2248DabneyRoadMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 512 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2248DabneyRoadMember |  |  |
Buildings and Improvements | 2,049 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2248DabneyRoadMember |  |  |
Net Improvements (Retirements) Since Acquisition | 57 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2248DabneyRoadMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 512 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2248DabneyRoadMember |  |  |
Buildings and Improvements | 2,106 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2248DabneyRoadMember |  |  |
Total | 2,618 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2248DabneyRoadMember |  |  |
Accumulated Depreciation at December 31, 2013 | 923 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2248DabneyRoadMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
2161-2179 Tomlynn Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A21612179TomlynnStreetMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 423 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A21612179TomlynnStreetMember |  |  |
Buildings and Improvements | 1,695 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A21612179TomlynnStreetMember |  |  |
Net Improvements (Retirements) Since Acquisition | 315 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A21612179TomlynnStreetMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 423 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A21612179TomlynnStreetMember |  |  |
Buildings and Improvements | 2,010 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A21612179TomlynnStreetMember |  |  |
Total | 2,433 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A21612179TomlynnStreetMember |  |  |
Accumulated Depreciation at December 31, 2013 | 842 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A21612179TomlynnStreetMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
2246 Dabney Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2246DabneyRoadMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 455 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2246DabneyRoadMember |  |  |
Buildings and Improvements | 1,822 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2246DabneyRoadMember |  |  |
Net Improvements (Retirements) Since Acquisition | 0 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2246DabneyRoadMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 455 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2246DabneyRoadMember |  |  |
Buildings and Improvements | 1,822 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2246DabneyRoadMember |  |  |
Total | 2,277 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2246DabneyRoadMember |  |  |
Accumulated Depreciation at December 31, 2013 | 797 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2246DabneyRoadMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
2251 Dabney Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2251DabneyRoadMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 387 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2251DabneyRoadMember |  |  |
Buildings and Improvements | 1,552 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2251DabneyRoadMember |  |  |
Net Improvements (Retirements) Since Acquisition | 95 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2251DabneyRoadMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 387 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2251DabneyRoadMember |  |  |
Buildings and Improvements | 1,647 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2251DabneyRoadMember |  |  |
Total | 2,034 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2251DabneyRoadMember |  |  |
Accumulated Depreciation at December 31, 2013 | 738 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2251DabneyRoadMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
2256 Dabney Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2256DabneyRoadMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 356 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2256DabneyRoadMember |  |  |
Buildings and Improvements | 1,427 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2256DabneyRoadMember |  |  |
Net Improvements (Retirements) Since Acquisition | 182 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2256DabneyRoadMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 356 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2256DabneyRoadMember |  |  |
Buildings and Improvements | 1,609 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2256DabneyRoadMember |  |  |
Total | 1,965 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2256DabneyRoadMember |  |  |
Accumulated Depreciation at December 31, 2013 | 751 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2256DabneyRoadMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
2130-2146 Tomlynn Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A21302146TomlynnStreetMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 353 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A21302146TomlynnStreetMember |  |  |
Buildings and Improvements | 1,416 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A21302146TomlynnStreetMember |  |  |
Net Improvements (Retirements) Since Acquisition | 214 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A21302146TomlynnStreetMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 353 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A21302146TomlynnStreetMember |  |  |
Buildings and Improvements | 1,630 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A21302146TomlynnStreetMember |  |  |
Total | 1,983 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A21302146TomlynnStreetMember |  |  |
Accumulated Depreciation at December 31, 2013 | 704 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A21302146TomlynnStreetMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
2120 Tomlynn Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2120TomlynnStreetMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 281 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2120TomlynnStreetMember |  |  |
Buildings and Improvements | 1,125 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2120TomlynnStreetMember |  |  |
Net Improvements (Retirements) Since Acquisition | 300 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2120TomlynnStreetMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 281 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2120TomlynnStreetMember |  |  |
Buildings and Improvements | 1,425 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2120TomlynnStreetMember |  |  |
Total | 1,706 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2120TomlynnStreetMember |  |  |
Accumulated Depreciation at December 31, 2013 | 625 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2120TomlynnStreetMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
2240 Dabney Road [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2240DabneyRoadMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 264 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2240DabneyRoadMember |  |  |
Buildings and Improvements | 1,059 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2240DabneyRoadMember |  |  |
Net Improvements (Retirements) Since Acquisition | 88 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2240DabneyRoadMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 264 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2240DabneyRoadMember |  |  |
Buildings and Improvements | 1,147 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2240DabneyRoadMember |  |  |
Total | 1,411 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2240DabneyRoadMember |  |  |
Accumulated Depreciation at December 31, 2013 | 478 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2240DabneyRoadMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
Boulders Land [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_BouldersLandMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 1,256 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_BouldersLandMember |  |  |
Buildings and Improvements | 0 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_BouldersLandMember |  |  |
Net Improvements (Retirements) Since Acquisition | 28 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_BouldersLandMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 1,259 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_BouldersLandMember |  |  |
Buildings and Improvements | 25 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_BouldersLandMember |  |  |
Total | 1,284 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_BouldersLandMember |  |  |
Accumulated Depreciation at December 31, 2013 | 2 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_BouldersLandMember |  |  |
5900 & 5950 La Place Court [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A59005950LaPlaceCourtMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 3,706 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A59005950LaPlaceCourtMember |  |  |
Buildings and Improvements | 11,185 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A59005950LaPlaceCourtMember |  |  |
Net Improvements (Retirements) Since Acquisition | 3,613 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A59005950LaPlaceCourtMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 3,955 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A59005950LaPlaceCourtMember |  |  |
Buildings and Improvements | 14,549 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A59005950LaPlaceCourtMember |  |  |
Total | 18,504 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A59005950LaPlaceCourtMember |  |  |
Accumulated Depreciation at December 31, 2013 | 3,645 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A59005950LaPlaceCourtMember |  |  |
Depreciable Life (Years) | 48 years |  |  |
5963 La Place Court [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A5963LaPlaceCourtMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 2,824 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A5963LaPlaceCourtMember |  |  |
Buildings and Improvements | 9,413 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A5963LaPlaceCourtMember |  |  |
Net Improvements (Retirements) Since Acquisition | 2,117 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A5963LaPlaceCourtMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 2,999 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A5963LaPlaceCourtMember |  |  |
Buildings and Improvements | 11,355 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A5963LaPlaceCourtMember |  |  |
Total | 14,354 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A5963LaPlaceCourtMember |  |  |
Accumulated Depreciation at December 31, 2013 | 2,486 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A5963LaPlaceCourtMember |  |  |
Depreciable Life (Years) | 55 years |  |  |
2035 Corte Del Nogal [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2035CorteDelNogalMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 3,261 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2035CorteDelNogalMember |  |  |
Buildings and Improvements | 6,077 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2035CorteDelNogalMember |  |  |
Net Improvements (Retirements) Since Acquisition | 1,167 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2035CorteDelNogalMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 3,499 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2035CorteDelNogalMember |  |  |
Buildings and Improvements | 7,006 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2035CorteDelNogalMember |  |  |
Total | 10,505 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2035CorteDelNogalMember |  |  |
Accumulated Depreciation at December 31, 2013 | 2,038 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A2035CorteDelNogalMember |  |  |
Depreciable Life (Years) | 39 years |  |  |
1200 Concord Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1200ConcordAvenueMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 6,395 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1200ConcordAvenueMember |  |  |
Buildings and Improvements | 24,664 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1200ConcordAvenueMember |  |  |
Net Improvements (Retirements) Since Acquisition | 808 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1200ConcordAvenueMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 6,515 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1200ConcordAvenueMember |  |  |
Buildings and Improvements | 25,352 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1200ConcordAvenueMember |  |  |
Total | 31,867 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1200ConcordAvenueMember |  |  |
Accumulated Depreciation at December 31, 2013 | 7,949 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1200ConcordAvenueMember |  |  |
Depreciable Life (Years) | 34 years |  |  |
1220 Concord Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1220ConcordAvenueMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 6,476 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1220ConcordAvenueMember |  |  |
Buildings and Improvements | 24,966 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1220ConcordAvenueMember |  |  |
Net Improvements (Retirements) Since Acquisition | 260 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1220ConcordAvenueMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 6,476 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1220ConcordAvenueMember |  |  |
Buildings and Improvements | 25,226 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1220ConcordAvenueMember |  |  |
Total | 31,702 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1220ConcordAvenueMember |  |  |
Accumulated Depreciation at December 31, 2013 | 7,622 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A1220ConcordAvenueMember |  |  |
Depreciable Life (Years) | 34 years |  |  |
155 Grand Avenue [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A155GrandAvenueMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 13,556 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A155GrandAvenueMember |  |  |
Buildings and Improvements | 54,267 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A155GrandAvenueMember |  |  |
Net Improvements (Retirements) Since Acquisition | 6,316 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A155GrandAvenueMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 13,556 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A155GrandAvenueMember |  |  |
Buildings and Improvements | 60,583 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A155GrandAvenueMember |  |  |
Total | 74,139 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A155GrandAvenueMember |  |  |
Accumulated Depreciation at December 31, 2013 | 12,652 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_A155GrandAvenueMember |  |  |
Depreciable Life (Years) | 40 years |  |  |
Two Kaiser Plaza [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoKaiserPlazaMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 7,841 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoKaiserPlazaMember |  |  |
Buildings and Improvements | 0 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoKaiserPlazaMember |  |  |
Net Improvements (Retirements) Since Acquisition | 0 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoKaiserPlazaMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 7,841 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoKaiserPlazaMember |  |  |
Buildings and Improvements | 0 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoKaiserPlazaMember |  |  |
Total | 7,841 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoKaiserPlazaMember |  |  |
Accumulated Depreciation at December 31, 2013 | 0 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_TwoKaiserPlazaMember |  |  |
Oakland Lot B [Member] |  |  |  |
Real Estate and Accumulated Depreciation [Line Items] |  |  |  |
Encumbrances at December 31, 2012 | 0 us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OaklandLotBMember |  |  |
Initial Cost [Abstract] |  |  |  |
Land | 4,342 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OaklandLotBMember |  |  |
Buildings and Improvements | 0 us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OaklandLotBMember |  |  |
Net Improvements (Retirements) Since Acquisition | 0 us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OaklandLotBMember |  |  |
Carrying Amount at Which Carried [Abstract] |  |  |  |
Land | 4,342 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OaklandLotBMember |  |  |
Buildings and Improvements | 0 us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OaklandLotBMember |  |  |
Total | 4,342 us-gaap_RealEstateGrossAtCarryingValue / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OaklandLotBMember |  |  |
Accumulated Depreciation at December 31, 2013 | $ 0 us-gaap_RealEstateAccumulatedDepreciation / us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis = bdn_OaklandLotBMember |  |  |

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