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Investment In Real Estate - Quantitative Information About Level 3 Fair Value Measurements (Details) (Unobservable Inputs (Level 3), Contracted Price [Member], USD $) In Thousands, unless otherwise specified | 9 Months Ended
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Sep. 30, 2013 sqft Property
Unobservable Inputs (Level 3) | Contracted Price [Member] |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |
Number of industrial properties | 1
Gross leaseable area | 500,000
Fair value of property | $ 6,875

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- Definition Gross Leaseable Area + References No definition available. + Details
Name: | fr_GrossLeaseableArea
Namespace Prefix: | fr_
Data Type: | num:areaItemType
Balance Type: | na
Period Type: | duration

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- Definition Number Of Industrial Properties + References No definition available. + Details
Name: | fr_NumberOfIndustrialProperties
Namespace Prefix: | fr_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

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- Definition The fair value of a property based on Level 3 fair value measurements. + References No definition available. + Details
Name: | fr_RealEstatePropertyFairValueDisclosure
Namespace Prefix: | fr_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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- Details
Name: | us-gaap_FairValueInputsAssetsQuantitativeInformationLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration