Annual report pursuant to Section 13 and 15(d)

Consolidated Balance Sheets (Parenthetical)

v2.4.1.9
Consolidated Balance Sheets (Parenthetical) (USD $)
In Thousands, except Share data, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Allowance for doubtful accounts- AR $ 717us-gaap_AllowanceForDoubtfulAccountsReceivable $ 2,976us-gaap_AllowanceForDoubtfulAccountsReceivable
Allowance for deferred rent receivable 1,418ofc_AllowanceforDoubtfulAccountsDeferredRent 2,126ofc_AllowanceforDoubtfulAccountsDeferredRent
Common Shares of beneficial interest, par value (in dollars per share) $ 0.01us-gaap_CommonStockParOrStatedValuePerShare $ 0.01us-gaap_CommonStockParOrStatedValuePerShare
Common Shares of beneficial interest, shares authorized 125,000,000us-gaap_CommonStockSharesAuthorized 125,000,000us-gaap_CommonStockSharesAuthorized
Common Shares of beneficial interest, shares issued 93,255,284us-gaap_CommonStockSharesIssued 87,394,512us-gaap_CommonStockSharesIssued
Common Shares of beneficial interest, shares outstanding 93,255,284us-gaap_CommonStockSharesOutstanding 87,394,512us-gaap_CommonStockSharesOutstanding
Corporate Office Properties, L.P.    
Allowance for doubtful accounts- AR 717us-gaap_AllowanceForDoubtfulAccountsReceivable
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
2,976us-gaap_AllowanceForDoubtfulAccountsReceivable
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
Allowance for deferred rent receivable $ 1,418ofc_AllowanceforDoubtfulAccountsDeferredRent
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
$ 2,126ofc_AllowanceforDoubtfulAccountsDeferredRent
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
General Partner | Corporate Office Properties, L.P.    
Preferred Units, Outstanding 7,431,667us-gaap_PreferredUnitsOutstanding
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_GeneralPartnerMember
9,431,667us-gaap_PreferredUnitsOutstanding
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_GeneralPartnerMember
Common Shares of beneficial interest, shares outstanding 93,255,284us-gaap_CommonStockSharesOutstanding
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_GeneralPartnerMember
87,394,512us-gaap_CommonStockSharesOutstanding
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_GeneralPartnerMember
Limited Partner | Corporate Office Properties, L.P.    
Preferred Units, Outstanding 352,000us-gaap_PreferredUnitsOutstanding
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_LimitedPartnerMember
352,000us-gaap_PreferredUnitsOutstanding
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_LimitedPartnerMember
Common Shares of beneficial interest, shares outstanding 3,837,551us-gaap_CommonStockSharesOutstanding
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_LimitedPartnerMember
3,977,700us-gaap_CommonStockSharesOutstanding
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_LimitedPartnerMember