Indebtedness - Senior Unsecured Notes Repurchases (Detail) (2028 Notes [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2013
2028 Notes [Member]
Unsecured Senior Notes [Line Items]
Principal Amount Repurchased	$ 4,000
Purchase Price	$ 4,566

Principal amount of senior unsecured notes repurchased.

No definition available.

Name:	fr_PrincipalAmountOfSeniorUnsecuredNotesRepurchased
Namespace Prefix:	fr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration