CONSOLIDATED STATEMENT OF CHANGES IN EQUITY/ PARTNER'S CAPITAL - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Distributions in Excess of Accumulated Earnings	Accumulated Other Comprehensive (Loss) Income	Noncontrolling Interests	First Industrial, L.P.	First Industrial, L.P. General Partner Units	First Industrial, L.P. Limited Partner Units	First Industrial, L.P. Accumulated Other Comprehensive (Loss) Income	First Industrial, L.P. Noncontrolling Interests
Beginning Balance at Dec. 31, 2019	$ 1,798,263	$ 1,270	$ 2,140,847	$ (370,835)	$ (6,883)	$ 33,864
Beginning Balance at Dec. 31, 2019							$ 1,808,284	$ 1,750,656	$ 63,618	$ (7,013)	$ 1,023
Increase (Decrease) in Equity / Partners' Capital [Roll Forward]
Net Income	41,529			40,634		895	41,529	40,584	895		50
Other Comprehensive Income (Loss)	(14,488)				(14,175)	(313)	(14,488)			(14,488)
Stock Based Compensation Activity	(1,835)	0	(1,233)	(2,975)		2,373
Stock Based Compensation Activity							(1,835)	(4,208)	2,373
Common Stock Dividends and Unit Distributions	(32,488)			(31,874)		(614)
Unit Distributions							(32,488)	(31,874)	(614)
Conversion of Limited Partner Units to Common Stock / General Partner Units	0	2	2,062			(2,064)	0	2,064	(2,064)
Reallocation - Additional Paid-in Capital	0		(3,378)			3,378
Reallocation - Other Comprehensive Income	0				4	(4)
Contributions from Noncontrolling Interests							5				5
Distributions to Noncontrolling Interests							(366)				(366)
Ending Balance at Mar. 31, 2020	1,790,981	1,272	2,138,298	(365,050)	(21,054)	37,515
Ending Balance at Mar. 31, 2020							1,800,641	1,757,222	64,208	(21,501)	712
Beginning Balance at Dec. 31, 2019	1,798,263	1,270	2,140,847	(370,835)	(6,883)	33,864
Beginning Balance at Dec. 31, 2019							1,808,284	1,750,656	63,618	(7,013)	1,023
Increase (Decrease) in Equity / Partners' Capital [Roll Forward]
Net Income	114,662						114,662
Conversion of Limited Partner Units to Common Stock / General Partner Units	0	2	2,067			(2,069)	0	2,069	(2,069)
Ending Balance at Sep. 30, 2020	1,888,599	1,290	2,221,552	(357,682)	(19,969)	43,408
Ending Balance at Sep. 30, 2020							1,898,060	1,845,742	67,710	(20,388)	4,996
Beginning Balance at Mar. 31, 2020	1,790,981	1,272	2,138,298	(365,050)	(21,054)	37,515
Beginning Balance at Mar. 31, 2020							1,800,641	1,757,222	64,208	(21,501)	712
Increase (Decrease) in Equity / Partners' Capital [Roll Forward]
Net Income	36,426			35,669		757	36,426	35,575	757		94
Other Comprehensive Income (Loss)	(1,282)				(1,260)	(22)	(1,282)			(1,282)
Stock Based Compensation Activity	3,108	0	1,486	0		1,622
Stock Based Compensation Activity							3,108	1,486	1,622
Common Stock Dividends and Unit Distributions	(32,560)			(31,929)		(631)
Unit Distributions							(32,560)	(31,929)	(631)
Conversion of Limited Partner Units to Common Stock / General Partner Units	0	0	1			(1)	0	1	(1)
Reallocation - Additional Paid-in Capital	0		1,470			(1,470)
Reallocation - Other Comprehensive Income	0				6	(6)
Contributions from Noncontrolling Interests							12				12
Distributions to Noncontrolling Interests							(65)				(65)
Ending Balance at Jun. 30, 2020	1,796,673	1,272	2,141,255	(361,310)	(22,308)	37,764
Ending Balance at Jun. 30, 2020							1,806,280	1,762,355	65,955	(22,783)	753
Increase (Decrease) in Equity / Partners' Capital [Roll Forward]
Net Income	36,707			35,959		748	36,707	35,879	760		68
Other Comprehensive Income (Loss)	2,395				2,342	53	2,395			2,395
Issuance of Common Stock, Net of Issuance Costs	78,349	18	78,331				78,349	78,349
Stock Based Compensation Activity	3,079	0	1,486	0		1,593
Stock Based Compensation Activity							3,079	1,486	1,593
Common Stock Dividends and Unit Distributions	(32,925)			(32,331)		(594)
Unit Distributions							(32,925)	(32,331)	(594)
Conversion of Limited Partner Units to Common Stock / General Partner Units	0	0	4			(4)	0	4	(4)
Reallocation - Additional Paid-in Capital	0		476			(476)
Reallocation - Other Comprehensive Income	0				(3)	3
Contributions from Noncontrolling Interests	4,321					4,321	4,371				4,371
Distributions to Noncontrolling Interests							(196)				(196)
Ending Balance at Sep. 30, 2020	1,888,599	1,290	2,221,552	(357,682)	(19,969)	43,408
Ending Balance at Sep. 30, 2020							1,898,060	1,845,742	67,710	(20,388)	4,996
Beginning Balance at Dec. 31, 2020	1,947,320	1,290	2,224,691	(306,294)	(16,953)	44,586
Beginning Balance at Dec. 31, 2020							1,956,690	1,898,635	70,435	(17,308)	4,928
Increase (Decrease) in Equity / Partners' Capital [Roll Forward]
Net Income	63,583			62,198		1,385	63,583	62,176	1,389		18
Other Comprehensive Income (Loss)	6,755				6,607	148	6,755			6,755
Stock Based Compensation Activity	(1,055)	1	(1,347)	(2,294)		2,585
Stock Based Compensation Activity							(1,055)	(3,640)	2,585
Common Stock Dividends and Unit Distributions	(35,718)			(34,933)		(785)
Unit Distributions							(35,718)	(34,933)	(785)
Conversion of Limited Partner Units to Common Stock / General Partner Units	0	0	22			(22)	0	22	(22)
Reallocation - Additional Paid-in Capital	0		(2,110)			2,110
Reallocation - Other Comprehensive Income	0				34	(34)
Contributions from Noncontrolling Interests							29				29
Distributions to Noncontrolling Interests							(24)				(24)
Ending Balance at Mar. 31, 2021	1,980,885	1,291	2,221,256	(281,323)	(10,312)	49,973
Ending Balance at Mar. 31, 2021							1,990,260	1,922,260	73,602	(10,553)	4,951
Beginning Balance at Dec. 31, 2020	1,947,320	1,290	2,224,691	(306,294)	(16,953)	44,586
Beginning Balance at Dec. 31, 2020							1,956,690	1,898,635	70,435	(17,308)	4,928
Increase (Decrease) in Equity / Partners' Capital [Roll Forward]
Net Income	160,163						160,163
Conversion of Limited Partner Units to Common Stock / General Partner Units	0	1	1,386			(1,387)	0	1,387	(1,387)
Ending Balance at Sep. 30, 2021	2,073,582	1,303	2,287,232	(257,092)	(8,386)	50,525
Ending Balance at Sep. 30, 2021							2,082,911	2,008,725	77,815	(8,575)	4,946
Beginning Balance at Mar. 31, 2021	1,980,885	1,291	2,221,256	(281,323)	(10,312)	49,973
Beginning Balance at Mar. 31, 2021							1,990,260	1,922,260	73,602	(10,553)	4,951
Increase (Decrease) in Equity / Partners' Capital [Roll Forward]
Net Income	53,161			51,936		1,225	53,161	51,913	1,227		21
Other Comprehensive Income (Loss)	292				282	10	292			292
Stock Based Compensation Activity	3,451	0	1,023	0		2,428
Stock Based Compensation Activity							3,451	1,023	2,428
Common Stock Dividends and Unit Distributions	(35,741)			(34,930)		(811)
Unit Distributions							(35,741)	(34,930)	(811)
Reallocation - Additional Paid-in Capital	0		2,282			(2,282)
Reallocation - Other Comprehensive Income	0				4	(4)
Distributions to Noncontrolling Interests							(23)				(23)
Ending Balance at Jun. 30, 2021	2,002,048	1,291	2,224,561	(264,317)	(10,026)	50,539
Ending Balance at Jun. 30, 2021							2,011,400	1,940,266	76,446	(10,261)	4,949
Increase (Decrease) in Equity / Partners' Capital [Roll Forward]
Net Income	43,419			42,446		973	43,419	42,424	975		20
Other Comprehensive Income (Loss)	1,686				1,648	38	1,686			1,686
Issuance of Common Stock, Net of Issuance Costs	58,811	11	58,800				58,811	58,811
Stock Based Compensation Activity	3,508	0	1,080	0		2,428
Stock Based Compensation Activity							3,508	1,080	2,428
Common Stock Dividends and Unit Distributions	(35,890)			(35,221)		(669)
Unit Distributions							(35,890)	(35,221)	(669)
Conversion of Limited Partner Units to Common Stock / General Partner Units	0	1	1,364			(1,365)	0	1,365	(1,365)
Reallocation - Additional Paid-in Capital	0		1,427			(1,427)
Reallocation - Other Comprehensive Income	0				(8)	8
Contributions from Noncontrolling Interests							6				6
Distributions to Noncontrolling Interests							(29)				(29)
Ending Balance at Sep. 30, 2021	$ 2,073,582	$ 1,303	$ 2,287,232	$ (257,092)	$ (8,386)	$ 50,525
Ending Balance at Sep. 30, 2021							$ 2,082,911	$ 2,008,725	$ 77,815	$ (8,575)	$ 4,946