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Income Taxes - Income Tax Purpose Distribution Paid to Preferred Shareholders are Classified as Ordinary Income (Parenthetical) (Detail) (Series J Preferred Stock [Member]) | 12 Months Ended
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Dec. 31, 2012
Income Tax [Line Items] |
Depositary Shares of Series J Preferred Stock redeemed | 2,000,000
Depositary Shares [Member] |
Income Tax [Line Items] |
Depositary Shares of Series J Preferred Stock redeemed | 2,000,000

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- Details
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Namespace Prefix: | fr_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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- Definition Preferred Stock Redeemed Shares + References No definition available. + Details
Name: | fr_PreferredStockRedeemedShares
Namespace Prefix: | fr_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration