CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
CASH FLOWS FROM OPERATING ACTIVITIES:
Net Income	$ 43,419	$ 36,707	$ 160,163	$ 114,662
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities:
Depreciation			80,309	76,580
Amortization of Debt Issuance Costs	782	905	2,666	2,477
Other Amortization, including Equity Based Compensation			23,861	26,776
Equity in Loss of Joint Ventures	15	162	154	236
Gain on Sale of Real Estate	(8,879)	(6,525)	(66,378)	(29,594)
Gain on Involuntary Conversion			0	(6,476)
Straight-line Rental Income and Expense, Net			(12,826)	(6,481)
(Increase) Decrease in Tenant Accounts Receivable, Prepaid Expenses and Other Assets, Net			(5,348)	3,149
Increase in Accounts Payable, Accrued Expenses, Other Liabilities, Rents Received in Advance and Security Deposits			13,836	8,810
Net Cash Provided by Operating Activities			196,437	190,139
CASH FLOWS FROM INVESTING ACTIVITIES:
Acquisitions of Real Estate			(224,954)	(184,883)
Additions to Investment in Real Estate and Non-Acquisition Tenant Improvements and Lease Costs			(197,980)	(150,908)
Net Proceeds from Sales of Investments in Real Estate, Including Sales-Type Lease Receivable			114,644	110,049
Contributions to and Investments in Joint Ventures			(1,321)	(42,744)
Distributions from Joint Ventures			21,407	0
Proceeds from Involuntary Conversion			0	6,476
Increase in Escrow Deposits and Other Investing Activity			(3,398)	(12,345)
Net Cash Used in Investing Activities			(291,602)	(274,355)
CASH FLOWS FROM FINANCING ACTIVITIES:
Financing and Equity Issuance Costs			(6,365)	(3,329)
Proceeds from the Issuance of Common Stock, Net of Underwriter's Discount			59,008	78,718
Tax Paid on Vested Equity Compensation			(5,126)	(5,944)
Common Stock Dividends and Unit Distributions Paid			(103,893)	(94,493)
Contributions from Noncontrolling Interests			0	4,321
Repayments on Mortgage Loans Payable			(61,097)	(18,654)
Proceeds from Senior Unsecured Notes			0	300,000
Proceeds from Unsecured Credit Facility			159,000	247,000
Repayments on Unsecured Credit Facility			(85,000)	(405,000)
Net Cash (Used in) Provided by Financing Activities			(43,473)	102,619
Net (Decrease) Increase in Cash, Cash Equivalents and Restricted Cash			(138,638)	18,403
Cash, Cash Equivalents and Restricted Cash, Beginning of Year			199,658	152,718
Cash, Cash Equivalents and Restricted Cash, End of Period	61,020	171,121	61,020	171,121
SUPPLEMENTAL INFORMATION TO STATEMENTS OF CASH FLOWS:
Interest Expense Capitalized in Connection with Development Activity			8,150	5,029
Cash Paid for Operating Lease Liabilities			2,407	2,175
Supplemental Schedule of Non-Cash Operating Activities:
Operating Lease Liabilities Arising from Obtaining Right-of-Use Assets			354	1,208
Supplemental Schedule of Non-Cash Investing and Financing Activities:
Dividends and Distributions Payable	36,701	33,577	36,701	33,577
Exchange of Limited Partnership Units for Common Stock/General Partnership Units:
Conversion of Limited Partner Units to Common Stock / General Partner Units	0	0	0	0
Assumption of Escrow in Connection with the Acquisition of Real Estate			3,611	0
Assumption of Liabilities in Connection with the Acquisition of Real Estate			3,451	6,542
Accounts Payable Related to Construction in Progress and Additions to Investment in Real Estate			66,092	24,385
Tenant Improvements Funded by Tenant			16,239	0
Write-off of Fully Depreciated Assets			(25,106)	(30,935)
Noncontrolling Interests
CASH FLOWS FROM OPERATING ACTIVITIES:
Net Income	973	748
Exchange of Limited Partnership Units for Common Stock/General Partnership Units:
Conversion of Limited Partner Units to Common Stock / General Partner Units	(1,365)	(4)	(1,387)	(2,069)
Common Stock
Exchange of Limited Partnership Units for Common Stock/General Partnership Units:
Conversion of Limited Partner Units to Common Stock / General Partner Units	1	0	1	2
Additional Paid-in Capital
Exchange of Limited Partnership Units for Common Stock/General Partnership Units:
Conversion of Limited Partner Units to Common Stock / General Partner Units	1,364	4	1,386	2,067
First Industrial, L.P.
CASH FLOWS FROM OPERATING ACTIVITIES:
Net Income	43,419	36,707	160,163	114,662
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities:
Depreciation			80,309	76,580
Amortization of Debt Issuance Costs	782	905	2,666	2,477
Other Amortization, including Equity Based Compensation			23,861	26,776
Equity in Loss of Joint Ventures	15	162	154	236
Gain on Sale of Real Estate	(8,879)	(6,525)	(66,378)	(29,594)
Gain on Involuntary Conversion			0	(6,476)
Straight-line Rental Income and Expense, Net			(12,826)	(6,481)
(Increase) Decrease in Tenant Accounts Receivable, Prepaid Expenses and Other Assets, Net			(5,307)	3,709
Increase in Accounts Payable, Accrued Expenses, Other Liabilities, Rents Received in Advance and Security Deposits			13,836	8,810
Net Cash Provided by Operating Activities			196,478	190,699
CASH FLOWS FROM INVESTING ACTIVITIES:
Acquisitions of Real Estate			(224,954)	(184,883)
Additions to Investment in Real Estate and Non-Acquisition Tenant Improvements and Lease Costs			(197,980)	(150,908)
Net Proceeds from Sales of Investments in Real Estate, Including Sales-Type Lease Receivable			114,644	110,049
Contributions to and Investments in Joint Ventures			(1,321)	(42,744)
Distributions from Joint Ventures			21,407	0
Proceeds from Involuntary Conversion			0	6,476
Increase in Escrow Deposits and Other Investing Activity			(3,398)	(12,345)
Net Cash Used in Investing Activities			(291,602)	(274,355)
CASH FLOWS FROM FINANCING ACTIVITIES:
Financing and Equity Issuance Costs			(6,365)	(3,329)
Proceeds from the Issuance of Common Stock, Net of Underwriter's Discount			59,008	(78,718)
Tax Paid on Vested Equity Compensation			(5,126)	(5,944)
Common Stock Dividends and Unit Distributions Paid			(103,893)	(94,493)
Contributions from Noncontrolling Interests			35	4,388
Distributions to Noncontrolling Interests			(76)	(627)
Repayments on Mortgage Loans Payable			(61,097)	(18,654)
Proceeds from Senior Unsecured Notes			0	300,000
Proceeds from Unsecured Credit Facility			159,000	247,000
Repayments on Unsecured Credit Facility			(85,000)	(405,000)
Net Cash (Used in) Provided by Financing Activities			(43,514)	102,059
Net (Decrease) Increase in Cash, Cash Equivalents and Restricted Cash			(138,638)	18,403
Cash, Cash Equivalents and Restricted Cash, Beginning of Year			199,658	152,718
Cash, Cash Equivalents and Restricted Cash, End of Period	61,020	171,121	61,020	171,121
SUPPLEMENTAL INFORMATION TO STATEMENTS OF CASH FLOWS:
Interest Expense Capitalized in Connection with Development Activity			8,150	5,029
Cash Paid for Operating Lease Liabilities			2,407	2,175
Supplemental Schedule of Non-Cash Operating Activities:
Operating Lease Liabilities Arising from Obtaining Right-of-Use Assets			354	1,208
Supplemental Schedule of Non-Cash Investing and Financing Activities:
Dividends and Distributions Payable	36,701	33,577	36,701	33,577
Exchange of Limited Partnership Units for Common Stock/General Partnership Units:
Conversion of Limited Partner Units to Common Stock / General Partner Units	0	0	0	0
Assumption of Escrow in Connection with the Acquisition of Real Estate			3,611	0
Assumption of Liabilities in Connection with the Acquisition of Real Estate			3,451	6,542
Accounts Payable Related to Construction in Progress and Additions to Investment in Real Estate			66,092	24,385
Tenant Improvements Funded by Tenant			16,239	0
Write-off of Fully Depreciated Assets			(25,106)	(30,935)
First Industrial, L.P. | Limited Partner Units
CASH FLOWS FROM OPERATING ACTIVITIES:
Net Income	975	760
Exchange of Limited Partnership Units for Common Stock/General Partnership Units:
Conversion of Limited Partner Units to Common Stock / General Partner Units	(1,365)	(4)	(1,387)	(2,069)
First Industrial, L.P. | General Partner Units
CASH FLOWS FROM OPERATING ACTIVITIES:
Net Income	42,424	35,879
Exchange of Limited Partnership Units for Common Stock/General Partnership Units:
Conversion of Limited Partner Units to Common Stock / General Partner Units	$ 1,365	$ 4	$ 1,387	$ 2,069