Quarterly report pursuant to Section 13 or 15(d)

Equity (Details)

v3.19.3
Equity (Details) - USD ($)
$ / shares in Units, $ in Thousands
 3 Months Ended 9 Months Ended
Sep. 23, 2019
Sep. 22, 2019
Jul. 31, 2019
Mar. 27, 2019
Sep. 30, 2019
Sep. 30, 2018
Sep. 30, 2019
Sep. 30, 2018
Dec. 31, 2018
Class of Stock [Line Items]                  
Preferred units in COPLP         $ 8,800   $ 8,800   $ 8,800
Conversion of common units to common shares (in units/shares)         97,539 1,841,810 103,039 1,895,627  
Dividends declared per share (in usd per share)         $ 0.275 $ 0.275 $ 0.825 $ 0.825  
Common Shares | Forward Equity Sale Agreement                  
Class of Stock [Line Items]                  
Number of shares issued       1,600,000          
Proceeds from common shares issued under forward equity sale agreements       $ 46,500          
Common Shares | 2018 Common Stock Issued to Public Under At-the-Market Program                  
Class of Stock [Line Items]                  
Aggregate gross sales price         $ 300,000   $ 300,000    
Corporate Office Properties, L.P.                  
Class of Stock [Line Items]                  
Dividends declared per share (in usd per share)         $ 0.275 $ 0.275 $ 0.825 $ 0.825  
Series I Preferred Units | Corporate Office Properties, L.P.                  
Class of Stock [Line Items]                  
Number of limited partners' preferred units outstanding (in units)         352,000   352,000    
Preferred units in COPLP         $ 8,800   $ 8,800    
Liquidation preference of preferred stock per share (in usd per share)         $ 25.00   $ 25.00    
Preferred stock dividend rate (percent) 3.50% 7.50%              
Preferred stock redemption notification period     6 months