Accumulated Other Comprehensive Income (Changes in AOCI) (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2019 USD ($)
Accumulated Other Comprehensive Income [Line Items]
Beginning Balance	$ 1,679,911
Ending Balance	1,674,403
Derivative Instruments
Accumulated Other Comprehensive Income [Line Items]
Beginning Balance	3,574
Other Comprehensive Loss Before Reclassifications	(9,715)
Amounts Reclassified from Accumulated Other Comprehensive (Loss) Income	(1,078)
Net Current Period Other Comprehensive Loss	(10,793)
Ending Balance	(7,219)
Comprehensive (Income) Loss Attributable to Noncontrolling Interest of the Company
Accumulated Other Comprehensive Income [Line Items]
Beginning Balance	(72)
Other Comprehensive Loss Before Reclassifications	233
Amounts Reclassified from Accumulated Other Comprehensive (Loss) Income	0
Net Current Period Other Comprehensive Loss	233
Ending Balance	161
Accumulated Other Comprehensive Income (Loss) of the Company
Accumulated Other Comprehensive Income [Line Items]
Beginning Balance	3,502
Other Comprehensive Loss Before Reclassifications	(9,482)
Amounts Reclassified from Accumulated Other Comprehensive (Loss) Income	(1,078)
Net Current Period Other Comprehensive Loss	(10,560)
Ending Balance	(7,058)
First Industrial, L.P. | Accumulated Other Comprehensive Income (Loss) of the Operating Partnership
Accumulated Other Comprehensive Income [Line Items]
Beginning Balance	3,574
Other Comprehensive Loss Before Reclassifications	(9,715)
Amounts Reclassified from Accumulated Other Comprehensive (Loss) Income	(1,078)
Net Current Period Other Comprehensive Loss	(10,793)
Ending Balance	$ (7,219)