CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
CASH FLOWS FROM OPERATING ACTIVITIES:
Net Income		$ 243,881	$ 167,334	$ 208,301
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities:
Depreciation		98,333	94,626	94,078
Amortization of Debt Issuance Costs		3,218	3,404	3,162
Other Amortization, including Stock Based Compensation		28,780	26,976	29,252
Impairment of Real Estate		0	2,756	0
Provision for Bad Debt		0	350	177
Equity in (Income) Loss of Joint Venture		(16,235)	276	0
Distributions from Joint Venture		15,959	0	0
Gain on Sale of Real Estate	[1]	(124,942)	(81,600)	(131,269)
Loss from Retirement of Debt		0	39	1,775
Gain on Casualty and Involuntary Conversion		0	(392)	(1,321)
Payments to Settle Derivative Instruments		(3,149)	0	0
Straight-line Rental Income and Expense, Net		(10,884)	(2,165)	(5,299)
Increase in Tenant Accounts Receivable, Prepaid Expenses and Other Assets, Net and Operating Lease Right-of-Use Assets		(11,523)	(4,199)	(5,829)
Increase (Decrease) in Accounts Payable, Accrued Expenses, Other Liabilities, Rents Received in Advance and Security Deposits and Operating Lease Liabilities		22,095	3,090	(465)
Net Cash Provided by Operating Activities		245,533	210,495	192,562
CASH FLOWS FROM INVESTING ACTIVITIES:
Acquisitions of Real Estate		(152,744)	(157,787)	(175,303)
Additions to Investment in Real Estate and Non-Acquisition Tenant Improvements and Lease Costs		(294,633)	(224,466)	(146,003)
Net Proceeds from Sales of Investments in Real Estate		254,416	184,783	228,102
(Increase) Decrease in Escrows		(23,113)	(1,326)	564
Proceeds from Casualty and Involuntary Conversion		0	906	10,094
Contributions to and Investments in Joint Venture		(210)	(25,190)	0
Distributions from Joint Venture		8,711	1,829	0
Other Investing Activity		2,187	(2,147)	51
Net Cash Used in Investing Activities		(205,386)	(223,398)	(82,495)
CASH FLOWS FROM FINANCING ACTIVITIES:
Financing and Equity Issuance Costs		(954)	(2,975)	(6,864)
Proceeds from the Issuance of Common Stock/Contribution of General Partner Units		0	145,584	74,880
Tax Paid on Shares Withheld		(4,384)	(6,020)	(2,401)
Common Stock Dividends and Unit Distributions Paid		(117,214)	(109,649)	(100,524)
Repayments on Mortgage Loans Payable		(123,250)	(165,646)	(46,832)
Prepayments of Penalties Associated with Retirement of Debt		0	0	(1,453)
Proceeds from Senior Unsecured Notes		150,000	300,000	200,000
Repayments of Senior Unsecured Notes		0	0	(156,852)
Proceeds from Unsecured Credit Facility		415,000	237,000	429,000
Repayments on Unsecured Credit Facility		(257,000)	(381,500)	(474,000)
Net Cash Provided by (Used in) Financing Activities		62,198	16,794	(85,046)
Net Increase in Cash, Cash Equivalents and Restricted Cash		102,345	3,891	25,021
Cash, Cash Equivalents and Restricted Cash, Beginning of Year		50,373	46,482	21,461
Cash, Cash Equivalents and Restricted Cash, End of Year		152,718	50,373	46,482
SUPPLEMENTAL INFORMATION TO STATEMENTS OF CASH FLOWS:
Interest Paid, Net of Interest Expense Capitalized in Connection with Development Activity		47,801	47,408	56,844
Interest Expense Capitalized in Connection with Development Activity		5,757	5,869	4,353
Income Taxes Paid		3,583	457	769
Cash Paid for Operating Lease Liabilities		2,084	0	0
Supplemental Schedule of Non-Cash Operating Activities:
Operating Lease Liabilities Arising from Obtaining Right-of-Use Assets		22,871	0	0
Supplemental Schedule of Non-Cash Investing and Financing Activities:
Dividends and Distributions Payable		30,567	28,845	27,016
Exchange of Limited Partner Units for Common Stock/General Partner Units
Conversion of Limited Partner Units to Common Stock / General Partner Units		0	0	0
Lease Reclassification from Operating Lease to Sales-Type Lease:
Land		(957,478)	(909,318)
Deferred Rent Receivables, Net		(77,703)	(71,079)
Assumption of Indebtedness and Other Liabilities in Connection with the Acquisition of Real Estate		1,466	11,878	1,269
Accounts Payable Related to Construction in Progress and Additions to Investment in Real Estate		51,107	31,545	38,597
Write-off of Fully Depreciated Assets		(37,892)	(43,654)	(35,560)
Sales Type Lease
Lease Reclassification from Operating Lease to Sales-Type Lease:
Sales-type Lease, Lease Receivable		54,521	0	0
Land		(24,803)	0	0
Building Net Of Accumulated Depreciation		(17,845)	0	0
Deferred Rent Receivables, Net		(2,073)	0	0
Other Assets Net Of Accumulated Amortization		(1,194)	0	0
Sales-type Lease, Selling Profit (Loss)		8,606	0	0
Noncontrolling Interest
CASH FLOWS FROM OPERATING ACTIVITIES:
Net Income		5,106	4,095	6,845
Exchange of Limited Partner Units for Common Stock/General Partner Units
Conversion of Limited Partner Units to Common Stock / General Partner Units		(7,196)	(16,605)	(364)
Common Stock
Exchange of Limited Partner Units for Common Stock/General Partner Units
Conversion of Limited Partner Units to Common Stock / General Partner Units		5	13	0
Additional Paid-in- Capital
Exchange of Limited Partner Units for Common Stock/General Partner Units
Conversion of Limited Partner Units to Common Stock / General Partner Units		7,191	16,592	364
First Industrial, L.P.
CASH FLOWS FROM OPERATING ACTIVITIES:
Net Income		243,881	167,334	208,301
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities:
Depreciation		98,333	94,626	94,078
Amortization of Debt Issuance Costs		3,218	3,404	3,162
Other Amortization, including Stock Based Compensation		28,780	26,976	29,252
Impairment of Real Estate		0	2,756	0
Provision for Bad Debt		0	350	177
Equity in (Income) Loss of Joint Venture		(16,235)	276	0
Distributions from Joint Venture		15,959	0	0
Gain on Sale of Real Estate		(124,942)	(81,600)	(131,269)
Loss from Retirement of Debt		0	39	1,775
Gain on Casualty and Involuntary Conversion		0	(392)	(1,321)
Payments to Settle Derivative Instruments		(3,149)	0	0
Straight-line Rental Income and Expense, Net		(10,884)	(2,165)	(5,299)
Increase in Tenant Accounts Receivable, Prepaid Expenses and Other Assets, Net and Operating Lease Right-of-Use Assets		(11,436)	(4,189)	(5,510)
Increase (Decrease) in Accounts Payable, Accrued Expenses, Other Liabilities, Rents Received in Advance and Security Deposits and Operating Lease Liabilities		22,095	3,090	(465)
Net Cash Provided by Operating Activities		245,620	210,505	192,881
CASH FLOWS FROM INVESTING ACTIVITIES:
Acquisitions of Real Estate		(152,744)	(157,787)	(175,303)
Additions to Investment in Real Estate and Non-Acquisition Tenant Improvements and Lease Costs		(294,633)	(224,466)	(146,003)
Net Proceeds from Sales of Investments in Real Estate		254,416	184,783	228,102
(Increase) Decrease in Escrows		(23,113)	(1,326)	565
Proceeds from Casualty and Involuntary Conversion		0	906	10,094
Contributions to and Investments in Joint Venture		(210)	(25,190)	0
Distributions from Joint Venture		8,711	1,829	0
Other Investing Activity		2,187	(2,147)	51
Net Cash Used in Investing Activities		(205,386)	(223,398)	(82,494)
CASH FLOWS FROM FINANCING ACTIVITIES:
Financing and Equity Issuance Costs		(954)	(2,975)	(6,864)
Proceeds from the Issuance of Common Stock/Contribution of General Partner Units		0	145,584	74,880
Tax Paid on Shares Withheld		(4,384)	(6,020)	(2,401)
Common Stock Dividends and Unit Distributions Paid		(117,214)	(109,649)	(100,524)
Contributions from Noncontrolling Interests		32	126	40
Distributions to Noncontrolling Interests		(119)	(136)	(360)
Repayments on Mortgage Loans Payable		(123,250)	(165,646)	(46,832)
Prepayments of Penalties Associated with Retirement of Debt		0	0	(1,453)
Proceeds from Senior Unsecured Notes		150,000	300,000	200,000
Repayments of Senior Unsecured Notes		0	0	(156,852)
Proceeds from Unsecured Credit Facility		415,000	237,000	429,000
Repayments on Unsecured Credit Facility		(257,000)	(381,500)	(474,000)
Net Cash Provided by (Used in) Financing Activities		62,111	16,784	(85,366)
Net Increase in Cash, Cash Equivalents and Restricted Cash		102,345	3,891	25,021
Cash, Cash Equivalents and Restricted Cash, Beginning of Year		50,373	46,482	21,461
Cash, Cash Equivalents and Restricted Cash, End of Year		152,718	50,373	46,482
SUPPLEMENTAL INFORMATION TO STATEMENTS OF CASH FLOWS:
Interest Paid, Net of Interest Expense Capitalized in Connection with Development Activity		47,801	47,408	56,844
Interest Expense Capitalized in Connection with Development Activity		5,757	5,869	4,353
Income Taxes Paid		3,583	457	769
Cash Paid for Operating Lease Liabilities		2,084	0	0
Supplemental Schedule of Non-Cash Operating Activities:
Operating Lease Liabilities Arising from Obtaining Right-of-Use Assets		22,871	0	0
Supplemental Schedule of Non-Cash Investing and Financing Activities:
Dividends and Distributions Payable		30,567	28,845	27,016
Exchange of Limited Partner Units for Common Stock/General Partner Units
Conversion of Limited Partner Units to Common Stock / General Partner Units		0	0	0
Lease Reclassification from Operating Lease to Sales-Type Lease:
Land		(957,478)	(909,318)
Deferred Rent Receivables, Net		(77,703)	(71,079)
Assumption of Indebtedness and Other Liabilities in Connection with the Acquisition of Real Estate		1,466	11,878	1,269
Accounts Payable Related to Construction in Progress and Additions to Investment in Real Estate		51,107	31,545	38,597
Write-off of Fully Depreciated Assets		(37,892)	(43,654)	(35,560)
First Industrial, L.P. | Sales Type Lease
Lease Reclassification from Operating Lease to Sales-Type Lease:
Sales-type Lease, Lease Receivable		54,521	0	0
Land		(24,803)	0	0
Building Net Of Accumulated Depreciation		(17,845)	0	0
Deferred Rent Receivables, Net		(2,073)	0	0
Other Assets Net Of Accumulated Amortization		(1,194)	0	0
Sales-type Lease, Selling Profit (Loss)		8,606	0	0
First Industrial, L.P. | Limited Partner Units
CASH FLOWS FROM OPERATING ACTIVITIES:
Net Income		5,106	4,095	6,845
Exchange of Limited Partner Units for Common Stock/General Partner Units
Conversion of Limited Partner Units to Common Stock / General Partner Units		(7,196)	(16,605)	(364)
First Industrial, L.P. | General Partner Units
CASH FLOWS FROM OPERATING ACTIVITIES:
Net Income		238,522	163,151	201,313
Exchange of Limited Partner Units for Common Stock/General Partner Units
Conversion of Limited Partner Units to Common Stock / General Partner Units		$ 7,196	$ 16,605	$ 364

[1] ^(B) Gross proceeds and gain on sale of real estate include the sale of several land parcels for the years ended December 31, 2019, 2018 and 2017. In addition, included in the above table for the year ended December 31, 2019, is gross proceeds of $54,521 and gain on sale of $8,606 related to the reclassification of a lease from an operating lease to a sales-type lease. See Note 10 for additional information.