Earnings Per Share / Unit (EPS / EPU) - Computation of Basic and Diluted EPS / EPU (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Numerator:
Net Income Available to Common Stockholders / Unitholders and Participating Securities	$ 31,519	$ 13,917	$ 97,436	$ 30,302
Net Income Allocable to Participating Securities	(110)	(50)	(329)	(141)
Net Income Available to First Industrial Realty Trust, Inc.’s Common Stockholders	$ 31,409	$ 13,867	$ 97,107	$ 30,161
Denominator:
Weighted Average Shares / Units - Basic	116,467	110,356	114,491	110,338
LTIP Unit Awards (As Defined in Note 9)	397	492	318	397
Weighted Average Shares / Units - Diluted	116,864	110,848	114,809	110,735
Basic Earnings Per Share / Unit:
Net Income Available to Common Stockholders / Unitholders	$ 0.27	$ 0.13	$ 0.85	$ 0.27
Diluted Earnings Per Share / Unit:
Net Income Available to Common Stockholders / Unitholders	$ 0.27	$ 0.13	$ 0.85	$ 0.27
First Industrial, L.P.
Numerator:
Net Income Available to Common Stockholders / Unitholders and Participating Securities	$ 32,630	$ 14,438	$ 100,959	$ 31,539
Net Income Allocable to Participating Securities	(110)	(50)	(328)	(141)
Net Income Available to Unitholders	$ 32,520	$ 14,388	$ 100,631	$ 31,398
Denominator:
Weighted Average Shares / Units - Basic	120,740	114,720	118,781	114,705
LTIP Unit Awards (As Defined in Note 9)	397	492	318	397
Weighted Average Shares / Units - Diluted	121,137	115,212	119,099	115,102
Basic Earnings Per Share / Unit:
Net Income Available to Common Stockholders / Unitholders	$ 0.27	$ 0.13	$ 0.85	$ 0.27
Diluted Earnings Per Share / Unit:
Net Income Available to Common Stockholders / Unitholders	$ 0.27	$ 0.12	$ 0.84	$ 0.27