Earnings Per Share / Unit (EPS / EPU) - Additional Information (Details) - shares	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Service Awards/Service Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested Service Awards / Performance Awards	211,920	296,371
Service Awards/Service Units | Management
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested Service Awards / Performance Awards	211,920	296,371	405,436
First Industrial, L.P.
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested Service Awards / Performance Awards	444,407	421,928	405,436