XML 13 R48.htm IDEA: XBRL DOCUMENT
v2.4.0.6

Earnings Per Share (EPS) - Additional Information (Detail) | Mar. 31, 2013 | Mar. 31, 2012
--- | --- | ---
Earnings Per Share [Abstract] |  |
Unvested restricted stock awards outstanding | 490,591 | 756,815

X
- Definition Number of unvested restricted stock awards outstanding included in participating securities. + References No definition available. + Details
Name: | fr_NumberOfUnvestedRestrictedStockAwardsOutstandingIncludedInParticipatingSecurities
Namespace Prefix: | fr_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

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