Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2020	Oct. 23, 2020
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2020
Document Transition Report	false
Entity File Number	1-13102
Entity Registrant Name	FIRST INDUSTRIAL REALTY TRUST, INC.
Entity Incorporation, State or Country Code	MD
Entity Tax Identification Number	36-3935116
Entity Address, Address Line One	1 N. Wacker Drive, Suite 4200
Entity Address, City or Town	Chicago
Entity Address, State or Province	IL
Entity Address, Postal Zip Code	60606
City Area Code	312
Local Phone Number	344-4300
Title of 12(b) Security	Common Stock, par value $.01 per share
Trading Symbol	FR
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Entity Central Index Key	0000921825
Current Fiscal Year End Date	--12-31
Entity Common Stock, Shares Outstanding		129,050,312
First Industrial, L.P.
Entity Information [Line Items]
Document Type	10-Q
Document Period End Date	Sep. 30, 2020
Entity File Number	333-21873
Entity Registrant Name	FIRST INDUSTRIAL, L.P.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	36-3924586
Trading Symbol	FRFI
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Entity Central Index Key	0001033128
Current Fiscal Year End Date	--12-31