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v3.3.1.900

Income Taxes - Additional Information (Detail) | 12 Months Ended
--- | ---
Dec. 31, 2013 $ / shares
Series J Preferred Stock |
Income Tax [Line Items] |
Ordinary Income | $ 0.5085
Series K Preferred Stock |
Income Tax [Line Items] |
Ordinary Income | $ 0.9969

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- Definition Income Tax [Line Items] + References No definition available. + Details
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Namespace Prefix: | fr_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Ordinary income per share. + References No definition available. + Details
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Namespace Prefix: | fr_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | duration

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- Details
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Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=fr_SeriesKPreferredStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |