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Commitments and Contingencies - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified | Mar. 31, 2013 sqft building
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Commitments and Contingencies Disclosure [Abstract] |
Number of industrial propertiess committed to development | 3
Development of industrial buildings in square feet | 1,500,000
Estimated construction costs | $ 107,700
Estimated amount remaining to be funded | $ 32,300

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- Definition Square Feet Under Development + References No definition available. + Details
Name: | fr_DevelopmentOfIndustrialBuildingsInSquareFeet
Namespace Prefix: | fr_
Data Type: | num:areaItemType
Balance Type: | na
Period Type: | instant

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- Definition Estimated Total Construction Costs of Development Projects. + References No definition available. + Details
Name: | fr_EstimatedConstructionCosts
Namespace Prefix: | fr_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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- Definition Estimated construction cost to be funded. + References No definition available. + Details
Name: | fr_EstimatedConstructionCostToBeFunded
Namespace Prefix: | fr_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Number Of Buildings Under Construction + References No definition available. + Details
Name: | fr_NumberOfBuildingsUnderConstruction
Namespace Prefix: | fr_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

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- Details
Name: | us-gaap_CommitmentsAndContingenciesDisclosureAbstract
Namespace Prefix: | us-gaap_
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Balance Type: | na
Period Type: | duration