Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements (Details)

v3.3.0.814
Fair Value Measurements (Details) - USD ($)
$ in Thousands
Sep. 30, 2015
Dec. 31, 2014
Sep. 30, 2014
Dec. 31, 2013
Liabilities:        
Interest rate derivatives $ 5,844 $ 1,855    
Redeemable noncontrolling interest 19,608 18,417 $ 18,436 $ 17,758
Corporate Office Properties, L.P.        
Liabilities:        
Interest rate derivatives 5,844 $ 1,855    
Fair value measurement on a recurring basis        
Assets:        
Warrants to purchase common stock 42      
Assets 5,541      
Liabilities:        
Deferred compensation plan liability 5,499      
Interest rate derivatives 5,844      
Liabilities 11,343      
Redeemable noncontrolling interest 19,608      
Fair value measurement on a recurring basis | Mutual funds        
Assets:        
Marketable securities in deferred compensation plan 5,395      
Fair value measurement on a recurring basis | Other        
Assets:        
Marketable securities in deferred compensation plan 104      
Fair value measurement on a recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1)        
Assets:        
Assets 5,499      
Fair value measurement on a recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Mutual funds        
Assets:        
Marketable securities in deferred compensation plan 5,395      
Fair value measurement on a recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other        
Assets:        
Marketable securities in deferred compensation plan 104      
Fair value measurement on a recurring basis | Significant Other Observable Inputs (Level 2)        
Assets:        
Warrants to purchase common stock 42      
Assets 42      
Liabilities:        
Deferred compensation plan liability 5,499      
Interest rate derivatives 5,844      
Liabilities 11,343      
Fair value measurement on a recurring basis | Significant Unobservable Inputs (Level 3)        
Liabilities:        
Redeemable noncontrolling interest 19,608      
Fair value measurement on a recurring basis | Corporate Office Properties, L.P.        
Assets:        
Warrants to purchase common stock 42      
Liabilities:        
Interest rate derivatives 5,844      
Redeemable noncontrolling interest 19,608      
Fair value measurement on a recurring basis | Corporate Office Properties, L.P. | Significant Other Observable Inputs (Level 2)        
Assets:        
Warrants to purchase common stock 42      
Liabilities:        
Interest rate derivatives 5,844      
Fair value measurement on a recurring basis | Corporate Office Properties, L.P. | Significant Unobservable Inputs (Level 3)        
Liabilities:        
Redeemable noncontrolling interest $ 19,608