Quarterly report pursuant to Section 13 or 15(d)

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

v3.21.2
Real Estate Joint Ventures - Investments in Unconsolidated Real Estate Joint Ventures (Details)
$ in Thousands
Jun. 30, 2021
USD ($)
property
Jun. 02, 2021
Dec. 31, 2020
USD ($)
Unconsolidated Real Estate Joint Ventures      
Schedule of Equity Method Investments [Line Items]      
Number of real estate properties | property 19    
Carrying value of Investments $ 40,586   $ 29,303
B RE COPT DC JV II LLC      
Schedule of Equity Method Investments [Line Items]      
Nominal Ownership % 10.00%    
Number of real estate properties | property 8    
Carrying value of Investments $ 15,877   15,988
Difference between the joint venture's cost basis and the entity's share of B RE COPT’s underlying equity in the net assets acquired from GI-COPT $ 7,300   7,400
BREIT COPT DC JV LLC      
Schedule of Equity Method Investments [Line Items]      
Nominal Ownership % 10.00%    
Number of real estate properties | property 9    
Carrying value of Investments $ 12,840   13,315
B RE COPT DC JV III LLC      
Schedule of Equity Method Investments [Line Items]      
Nominal Ownership % 10.00% 10.00%  
Number of real estate properties | property 2    
Carrying value of Investments $ 11,869   $ 0