Annual report pursuant to Section 13 and 15(d)

Properties, Net (Narrative) (Details)

v3.22.4
Properties, Net (Narrative) (Details)
ft² in Thousands, $ in Thousands
 3 Months Ended 12 Months Ended
Jan. 10, 2023
USD ($)
property
Dec. 14, 2022
USD ($)
property
Jan. 25, 2022
USD ($)
Dec. 30, 2021
USD ($)
Jun. 02, 2021
USD ($)
property
Oct. 30, 2020
USD ($)
property
Sep. 30, 2020
USD ($)
Dec. 31, 2022
USD ($)
ft²
property
Dec. 31, 2021
USD ($)
ft²
property
Dec. 31, 2020
USD ($)
ft²
property
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]                    
Ownership percentage sold               90.00% 90.00% 90.00%
Discontinued Operation, Gain (Loss) on Disposal, Statement of Income or Comprehensive Income [Extensible Enumeration]               Discontinued operations    
Number of properties sold | property               2 2 2
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal, Statement of Income or Comprehensive Income [Extensible Enumeration]       Gain on sales of real estate       Gain on sales of real estate Gain on sales of real estate Gain on sales of real estate
Subsequent Event                    
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]                    
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal, Statement of Income or Comprehensive Income [Extensible Enumeration] Gain on sales of real estate                  
Quark JV LLC                    
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]                    
Nominal Ownership %   10.00%                
BRE- COPT 3                    
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]                    
Nominal Ownership %         10.00%          
BRE- COPT 2                    
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]                    
Nominal Ownership %           10.00%        
Newly-Formed Joint Venture | Subsequent Event                    
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]                    
Nominal Ownership % 10.00%                  
Baltimore, Maryland                    
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]                    
Impairment charges             $ 1,500      
Newly-developed properties placed in service                    
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]                    
Area of real estate property (in sqft or acres) | ft²               1,300 766 1,800
Number of real estate properties | property               9 8 11
Expansion of Fully-Operational Properties Placed in Service                    
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]                    
Area of real estate property (in sqft or acres) | ft²               14   42
Number of real estate properties | property               1   3
Properties under development                    
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]                    
Area of real estate property (in sqft or acres) | ft²               1,000    
Number of real estate properties | property               7    
Properties Under Development, Partially-Operational                    
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]                    
Number of real estate properties | property               2    
Redeveloped Property Placed in Service                    
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]                    
Area of real estate property (in sqft or acres) | ft²                   21
Data Center Shells in Northern Virginia | Disposed of by sale                    
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]                    
Number of real estate properties held for sale | property               3    
Ownership percentage sold   90.00%     90.00% 90.00%        
Transaction value   $ 67,000     $ 118,800 $ 89,700        
Number of properties sold | property   2     2 2        
Proceeds from sale   $ 60,300     $ 106,900 $ 80,700        
Gain on disposal               $ 19,200 $ 40,200 $ 30,000
Data Center Shells in Northern Virginia | Disposed of by sale | Subsequent Event                    
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]                    
Ownership percentage sold 90.00%                  
Transaction value $ 211,300                  
Number of properties sold | property 3                  
Proceeds from sale $ 190,200                  
Gain on disposal $ 49,000                  
Wholesale Data Center | Discontinued Operations, Disposed of by Sale                    
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]                    
Transaction value     $ 222,500              
Gain on disposal     $ 28,600         $ 28,564 $ 0 $ 0
Other Data Center Shells | Disposed of by sale                    
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]                    
Proceeds from sale       $ 30,000            
Gain on disposal       $ 25,900