Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements (Details)

v2.4.0.8
Fair Value Measurements (Details) (USD $)
In Thousands, unless otherwise specified
 9 Months Ended
Sep. 30, 2013
Dec. 31, 2012
Sep. 30, 2012
Sep. 30, 2013
Corporate Office Properties, L.P.
Dec. 31, 2012
Corporate Office Properties, L.P.
Sep. 30, 2013
Fair value measurement on a recurring basis
Quoted Prices in Active Markets for Identical Assets (Level 1)
Sep. 30, 2013
Fair value measurement on a recurring basis
Quoted Prices in Active Markets for Identical Assets (Level 1)
Corporate Office Properties, L.P.
Sep. 30, 2013
Fair value measurement on a recurring basis
Quoted Prices in Active Markets for Identical Assets (Level 1)
Mutual funds
Sep. 30, 2013
Fair value measurement on a recurring basis
Quoted Prices in Active Markets for Identical Assets (Level 1)
Common Shares
Sep. 30, 2013
Fair value measurement on a recurring basis
Quoted Prices in Active Markets for Identical Assets (Level 1)
Other
Sep. 30, 2013
Fair value measurement on a recurring basis
Significant Other Observable Inputs (Level 2)
Sep. 30, 2013
Fair value measurement on a recurring basis
Significant Other Observable Inputs (Level 2)
Corporate Office Properties, L.P.
Sep. 30, 2013
Fair value measurement on a recurring basis
Significant Unobservable Inputs (Level 3)
Sep. 30, 2013
Fair value measurement on a recurring basis
Significant Unobservable Inputs (Level 3)
Corporate Office Properties, L.P.
Sep. 30, 2013
Fair value measurement on a recurring basis
Total Estimated Fair Value
Sep. 30, 2013
Fair value measurement on a recurring basis
Total Estimated Fair Value
Corporate Office Properties, L.P.
Sep. 30, 2013
Fair value measurement on a recurring basis
Total Estimated Fair Value
Mutual funds
Sep. 30, 2013
Fair value measurement on a recurring basis
Total Estimated Fair Value
Common Shares
Sep. 30, 2013
Fair value measurement on a recurring basis
Total Estimated Fair Value
Other
Sep. 30, 2013
Redeemable Noncontrolling Interest
Minimum
Fair value measurement on a recurring basis
Significant Unobservable Inputs (Level 3)
Sep. 30, 2013
Redeemable Noncontrolling Interest
Maximum
Fair value measurement on a recurring basis
Significant Unobservable Inputs (Level 3)
Sep. 30, 2013
Redeemable Noncontrolling Interest
Weighted Average
Fair value measurement on a recurring basis
Significant Unobservable Inputs (Level 3)
Assets:                                            
Marketable securities in deferred compensation plan               $ 6,753 [1] $ 217 [1] $ 211 [1]             $ 6,753 [1] $ 217 [1] $ 211 [1]      
Common stock           520 [1] 520 [2]               520 [1] 520 [2]            
Interest rate derivatives 1,600 (6,185)                 5,195 [3] 5,195 [4]     5,195 [3] 5,195 [4]            
Warrants to purchase common stock                     301 [3] 301 [4]     301 [3] 301 [4]            
Assets           7,701 520       5,496 5,496 0 0 13,197 6,016            
Liabilities:                                            
Deferred compensation plan liability           7,181 [5]                 7,181 [5]              
Interest rate derivatives 3,595 6,185   3,595 6,185           3,595 3,595     3,595 3,595            
Liabilities           7,181         3,595       10,776              
Redeemable noncontrolling interest $ 16,789 $ 10,298 $ 9,932 $ 16,789 $ 10,298               $ 16,789 $ 16,789 $ 16,789 $ 16,789            
Discount rate                                       10.00% 20.00% 15.30%
[1] Included in the line entitled “restricted cash and marketable securities” on COPT’s consolidated balance sheet.
[2] Included in the line entitled “restricted cash and marketable securities” on COPLP’s consolidated balance sheet.
[3] Included in the line entitled “prepaid expenses and other assets” on COPT’s consolidated balance sheet.
[4] Included in the line entitled “prepaid expenses and other assets” on COPLP’s consolidated balance sheet.
[5] Included in the line entitled “other liabilities” on COPT’s consolidated balance sheet.