Quarterly report pursuant to Section 13 or 15(d)

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

v3.21.1
Real Estate Joint Ventures - Investments in Unconsolidated Real Estate Joint Ventures (Details)
$ in Thousands
Mar. 31, 2021
USD ($)
property
Dec. 31, 2020
USD ($)
Unconsolidated Real Estate Joint Ventures    
Schedule of Equity Method Investments [Line Items]    
Number of real estate properties | property 17  
Carrying value of Investments $ 28,934 $ 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 $ 15,840 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 $ 7,400 7,400
BREIT COPT    
Schedule of Equity Method Investments [Line Items]    
Nominal Ownership % 10.00%  
Number of real estate properties | property 9  
Carrying value of Investments $ 13,094 $ 13,315