Investments in Joint Ventures Condensed Combined Balance Sheets (Parenthetical) (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Real Estate and Other Assets Held for Sale, Accumulated Depreciation and Amortization	$ 0	$ 3,050
Corporate Joint Venture [Member]
Real Estate and Other Assets Held for Sale, Accumulated Depreciation and Amortization	40,387	0
Leasing Intangibles Held for Sale Accumulated Amortization	$ 3,208	$ 0

The cumulative amount of depreciation and amortization for the carrying amount as of the balance sheet date of investments in land and buildings held for sale, excluding real estate considered to be inventory of the entity.

No definition available.

Name:	fr_RealEstateHeldForSaleAccumulatedDepreciationAndAmortization
Namespace Prefix:	fr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant