Document and Entity Information - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2019
Feb. 12, 2020
Jun. 30, 2019
Entity Information [Line Items]      
Document Type 10-K    
Document Annual Report true    
Document Period End Date Dec. 31, 2019    
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 (First Industrial Realty Trust, Inc.)    
Trading Symbol FR    
Security Exchange Name NYSE    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Amendment Flag false    
Document Fiscal Year Focus 2019    
Document Fiscal Period Focus FY    
Entity Central Index Key 0000921825    
Current Fiscal Year End Date --12-31    
Entity Filer Category Large Accelerated Filer    
Entity Small Business false    
Entity Emerging Growth Company false    
Entity Shell Company false    
Entity Public Float     $ 4,593.5
Entity Common Stock, Shares Outstanding   127,036,879  
First Industrial, L.P.      
Entity Information [Line Items]      
Document Type 10-K    
Document Period End Date Dec. 31, 2019    
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 Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Amendment Flag false    
Document Fiscal Year Focus 2019    
Document Fiscal Period Focus FY    
Entity Central Index Key 0001033128    
Current Fiscal Year End Date --12-31    
Entity Filer Category Accelerated Filer    
Entity Small Business false    
Entity Emerging Growth Company false    
Entity Shell Company false