Earnings Per Share / Unit (EPS / EPU) - Computation of Basic and Diluted EPS / EPU (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Numerator:
Net Income Available to Common Stockholders / Unitholders and Participating Securities	$ 270,997	$ 195,989	$ 238,775
Net Income Allocable to Participating Securities	(299)	(314)	(518)
Net Income Available to Common Stockholders / Unitholders	$ 270,698	$ 195,675	$ 238,257
Denominator:
Weighted Average Shares/Units - Basic	129,688	127,711	126,392
Performance Units/Performance Units and certain Performance RLP Units	87	193	299
Weighted Average Shares / Units - Diluted	129,775	127,904	126,691
Basic Earnings Per Share / Unit:
Net Income Available to Common Stockholders/Unitholders	$ 2.09	$ 1.53	$ 1.89
Diluted Earnings Per Share / Unit:
Net Income Available to Common Stockholders/Unitholders	$ 2.09	$ 1.53	$ 1.88
First Industrial, L.P.
Numerator:
Net Income Available to Common Stockholders / Unitholders and Participating Securities	$ 277,038	$ 199,934	$ 243,628
Net Income Allocable to Participating Securities	(770)	(662)	(732)
Net Income Available to Common Stockholders / Unitholders	$ 276,268	$ 199,272	$ 242,896
Denominator:
Weighted Average Shares/Units - Basic	131,740	129,752	128,831
Performance Units/Performance Units and certain Performance RLP Units	497	375	410
Weighted Average Shares / Units - Diluted	132,237	130,127	129,241
Basic Earnings Per Share / Unit:
Net Income Available to Common Stockholders/Unitholders	$ 2.10	$ 1.54	$ 1.89
Diluted Earnings Per Share / Unit:
Net Income Available to Common Stockholders/Unitholders	$ 2.09	$ 1.53	$ 1.88