Quarterly report pursuant to Section 13 or 15(d)

Real Estate Joint Ventures - Investments in Unconsolidated Real Estate Joint Ventures (Details)

v3.20.2
Real Estate Joint Ventures - Investments in Unconsolidated Real Estate Joint Ventures (Details)
$ in Thousands
1 Months Ended
May 31, 2020
USD ($)
Sep. 30, 2020
USD ($)
property
Dec. 31, 2019
USD ($)
Unconsolidated Real Estate Joint Ventures      
Schedule of Equity Method Investments [Line Items]      
Number of Properties | property   15  
Carrying value of Investments   $ 49,662 $ 51,949
GI-COPT DC Partnership LLC      
Schedule of Equity Method Investments [Line Items]      
Nominal Ownership %   50.00%  
Number of Properties | property   6  
Carrying value of Investments   $ 36,135 37,816
Maximum cost reimbursement for development $ 6,000    
Variable Interest Entity, Not Primary Beneficiary | BREIT COPT DC JV LLC      
Schedule of Equity Method Investments [Line Items]      
Nominal Ownership %   10.00%  
Number of Properties | property   9  
Carrying value of Investments   $ 13,527 $ 14,133