CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues [Abstract]
Lease Revenue	$ 422,236	$ 398,822	$ 391,884
Other Revenue	3,748	5,132	4,518
Total Revenues	425,984	403,954	396,402
Expenses:
Property Expenses	116,585	116,854	113,494
General and Administrative	28,569	27,749	28,079
Depreciation and Other Amortization	121,229	116,459	116,364
Impairment of Real Estate	0	2,756	0
Total Expenses	266,383	263,818	257,937
Other Income (Expense):
Gain on Sale of Real Estate	124,942	81,600	131,269
Interest Expense	(50,273)	(50,775)	(57,199)
Amortization of Debt Issuance Costs	(3,218)	(3,404)	(3,162)
Settlement Gain on Derivative Instruments	0	0	1,896
Loss from Retirement of Debt	0	(39)	(1,775)
Total Other Income (Expense)	71,451	27,382	71,029
Income from Operations Before Equity in Income (Loss) of Joint Venture and Income Tax (Provision) Benefit	231,052	167,518	209,494
Equity in Income (Loss) of Joint Venture	16,235	(276)	0
Income Tax (Provision) Benefit	(3,406)	92	(1,193)
Net Income	243,881	167,334	208,301
Less: Net Income Attributable to the Noncontrolling Interest	(5,106)	(4,095)	(6,845)
Net Income Available to Common Stockholders / Unitholders and Participating Securities	$ 238,775	$ 163,239	$ 201,456
Basic Earnings Per Share / Unit:
Net Income Available to Common Stockholders/Unitholders	$ 1.89	$ 1.31	$ 1.70
Diluted Earnings Per Share / Unit:
Net Income Available to Common Stockholders/Unitholders	$ 1.88	$ 1.31	$ 1.69
Weighted Average Shares/Units Outstanding - Basic	126,392	123,804	118,272
Weighted Average Shares / Units Outstanding - Diluted	126,691	124,191	118,787
First Industrial, L.P.
Revenues [Abstract]
Lease Revenue	$ 422,236	$ 398,822	$ 391,884
Other Revenue	3,748	5,132	4,518
Total Revenues	425,984	403,954	396,402
Expenses:
Property Expenses	116,585	116,854	113,494
General and Administrative	28,569	27,749	28,079
Depreciation and Other Amortization	121,229	116,459	116,364
Impairment of Real Estate	0	2,756	0
Total Expenses	266,383	263,818	257,937
Other Income (Expense):
Gain on Sale of Real Estate	124,942	81,600	131,269
Interest Expense	(50,273)	(50,775)	(57,199)
Amortization of Debt Issuance Costs	(3,218)	(3,404)	(3,162)
Settlement Gain on Derivative Instruments	0	0	1,896
Loss from Retirement of Debt	0	(39)	(1,775)
Total Other Income (Expense)	71,451	27,382	71,029
Income from Operations Before Equity in Income (Loss) of Joint Venture and Income Tax (Provision) Benefit	231,052	167,518	209,494
Equity in Income (Loss) of Joint Venture	16,235	(276)	0
Income Tax (Provision) Benefit	(3,406)	92	(1,193)
Net Income	243,881	167,334	208,301
Less: Net Income Attributable to the Noncontrolling Interest	(253)	(88)	(143)
Net Income Available to Common Stockholders / Unitholders and Participating Securities	$ 243,628	$ 167,246	$ 208,158
Basic Earnings Per Share / Unit:
Net Income Available to Common Stockholders/Unitholders	$ 1.89	$ 1.31	$ 1.70
Diluted Earnings Per Share / Unit:
Net Income Available to Common Stockholders/Unitholders	$ 1.88	$ 1.31	$ 1.69
Weighted Average Shares/Units Outstanding - Basic	128,831	126,921	122,306
Weighted Average Shares / Units Outstanding - Diluted	129,241	127,308	122,821