Annual report pursuant to Section 13 and 15(d)

Consolidated Statements of Equity

v2.4.1.9
Consolidated Statements of Equity (USD $)
In Thousands, except Share data, unless otherwise specified
Total
USD ($)
Preferred Shares
USD ($)
Common Shares
USD ($)
Preferred Shares
USD ($)
Common Shares
USD ($)
Additional Paid-in Capital
USD ($)
Additional Paid-in Capital
Preferred Shares
USD ($)
Additional Paid-in Capital
Common Shares
USD ($)
Cumulative Distributions in Excess of Net Income
USD ($)
Accumulated Other Comprehensive Loss
USD ($)
Noncontrolling Interests
USD ($)
Corporate Office Properties, L.P.
USD ($)
Corporate Office Properties, L.P.
Preferred Shares
USD ($)
Corporate Office Properties, L.P.
Common Shares
USD ($)
Corporate Office Properties, L.P.
Common Shares
USD ($)
Corporate Office Properties, L.P.
Common Shares
Preferred Shares
USD ($)
Corporate Office Properties, L.P.
Common Shares
USD ($)
Corporate Office Properties, L.P.
Accumulated Other Comprehensive Loss
USD ($)
Corporate Office Properties, L.P.
Noncontrolling Interests
USD ($)
Corporate Office Properties, L.P.
Limited Partner
Corporate Office Properties, L.P.
Limited Partner
Preferred Shares
USD ($)
Corporate Office Properties, L.P.
General Partner
Corporate Office Properties, L.P.
General Partner
Preferred Shares
USD ($)
Balance at Dec. 31, 2011 $ 1,205,899us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest     $ 216,333us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
$ 720us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
$ 1,451,078us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
    $ (534,041)us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedDistributionsInExcessOfNetIncomeMember
$ (1,733)us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedOtherComprehensiveIncomeMember
$ 73,542us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
$ 1,205,899us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
    $ 972,107us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
    $ (1,837)us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedOtherComprehensiveIncomeMember
$ 10,496us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
  $ 8,800us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_LimitedPartnerMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
  $ 216,333us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_GeneralPartnerMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
Balance (preferred units) at Dec. 31, 2011                                         352,000us-gaap_PreferredUnitsOutstanding
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_LimitedPartnerMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
  8,121,667us-gaap_PreferredUnitsOutstanding
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_GeneralPartnerMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
Balance (in units/ shares) at Dec. 31, 2011 72,011,324us-gaap_CommonStockSharesOutstanding                           76,313,112us-gaap_CommonStockSharesOutstanding
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
               
Increase (Decrease) in Shareholders' Equity                                              
Conversion of common units to common shares (234,246, 311,343 and 140,149 shares in 2012, 2013 and 2014, respectively) 0us-gaap_StockIssuedDuringPeriodValueConversionOfUnits       2us-gaap_StockIssuedDuringPeriodValueConversionOfUnits
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
2,812us-gaap_StockIssuedDuringPeriodValueConversionOfUnits
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
        (2,814)us-gaap_StockIssuedDuringPeriodValueConversionOfUnits
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
                       
Shares issued to the public (6,900,000 preferred shares in 2012, 8,625,000, 4,485,000 and 5,520,000 common shares in 2012, 2013 and 2014, respectively)(in dollars)   165,652us-gaap_StockIssuedDuringPeriodValueNewIssues
/ us-gaap_StatementClassOfStockAxis
= us-gaap_PreferredStockMember
204,696us-gaap_StockIssuedDuringPeriodValueNewIssues
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
172,500us-gaap_StockIssuedDuringPeriodValueNewIssues
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
86us-gaap_StockIssuedDuringPeriodValueNewIssues
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
  (6,848)us-gaap_StockIssuedDuringPeriodValueNewIssues
/ us-gaap_StatementClassOfStockAxis
= us-gaap_PreferredStockMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
204,610us-gaap_StockIssuedDuringPeriodValueNewIssues
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
        165,652us-gaap_StockIssuedDuringPeriodValueNewIssues
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementClassOfStockAxis
= us-gaap_PreferredStockMember
204,696us-gaap_StockIssuedDuringPeriodValueNewIssues
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
  (6,848)us-gaap_StockIssuedDuringPeriodValueNewIssues
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementClassOfStockAxis
= us-gaap_PreferredStockMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
204,696us-gaap_StockIssuedDuringPeriodValueNewIssues
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
          172,500us-gaap_StockIssuedDuringPeriodValueNewIssues
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_GeneralPartnerMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
Shares issued to the public (in units/shares)       6,900,000us-gaap_StockIssuedDuringPeriodSharesNewIssues
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
8,625,000us-gaap_StockIssuedDuringPeriodSharesNewIssues
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
                  8,625,000us-gaap_StockIssuedDuringPeriodSharesNewIssues
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
              6,900,000us-gaap_StockIssuedDuringPeriodSharesNewIssues
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_GeneralPartnerMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
Stock redeemed or called during period (in units/ shares)       (2,200,000)us-gaap_StockRedeemedOrCalledDuringPeriodShares
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
                                    (2,200,000)us-gaap_StockRedeemedOrCalledDuringPeriodShares
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_GeneralPartnerMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
Redemption of preferred shares/units (2,200,000, 3,390,000 and 2,000,000 shares in 2012, 2013 and 2014, respectively) (55,000)us-gaap_StockRedeemedOrCalledDuringPeriodValue     (55,000)us-gaap_StockRedeemedOrCalledDuringPeriodValue
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
  1,827us-gaap_StockRedeemedOrCalledDuringPeriodValue
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
    (1,827)us-gaap_StockRedeemedOrCalledDuringPeriodValue
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedDistributionsInExcessOfNetIncomeMember
    (55,000)us-gaap_StockRedeemedOrCalledDuringPeriodValue
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
                    (55,000)us-gaap_StockRedeemedOrCalledDuringPeriodValue
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_GeneralPartnerMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
Exercise of share options (in units/shares) 61,624us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised                           61,624us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
               
Exercise of share options ( 61,624, 39,331 and 62,888 shares in 2012, 2013 and 2014, respectively)(in dollars) 928us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised       0us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
928us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
          928us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
    928us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
               
Share-based compensation 11,184us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue       1us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
11,183us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
          11,184us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
    11,184us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
               
Share-based compensation (in shares/units)                             160,643us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
               
Restricted common units/shares redemptions (139,851)us-gaap_StockRepurchasedDuringPeriodShares                           (139,851)us-gaap_StockRepurchasedDuringPeriodShares
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
               
Restricted common units/shares redemptions (139,851, 78,440 and 57,537 shares in 2012, 2013 and 2014, respectively) (in dollars) (3,379)us-gaap_StockRepurchasedDuringPeriodValue         (3,379)us-gaap_StockRepurchasedDuringPeriodValue
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
          (3,379)us-gaap_StockRepurchasedDuringPeriodValue
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
    (3,379)us-gaap_StockRepurchasedDuringPeriodValue
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
               
Adjustments to noncontrolling interests resulting from changes in ownership of COPLP 0us-gaap_NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance         (4,627)us-gaap_NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
        4,627us-gaap_NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
                       
Comprehensive income (loss) 18,927ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments               20,977ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedDistributionsInExcessOfNetIncomeMember
(3,702)ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedOtherComprehensiveIncomeMember
1,652ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
18,927ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
    (656)ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
    (3,871)ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedOtherComprehensiveIncomeMember
1,950ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
  660ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_LimitedPartnerMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
  20,844ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_GeneralPartnerMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
Dividends/Distributions (102,564)us-gaap_Dividends               (102,564)us-gaap_Dividends
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedDistributionsInExcessOfNetIncomeMember
    (107,841)us-gaap_Dividends
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
    (86,337)us-gaap_Dividends
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
          (660)us-gaap_Dividends
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_LimitedPartnerMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
  (20,844)us-gaap_Dividends
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_GeneralPartnerMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
Distributions to owners of common and preferred units in COPLP (5,277)ofc_MinorityInterestDecreaseFromDistributionsToOperatingPartnershipNoncontrollingInterestHolders                   (5,277)ofc_MinorityInterestDecreaseFromDistributionsToOperatingPartnershipNoncontrollingInterestHolders
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
                       
Distributions to noncontrolling interests (655)ofc_MinorityInterestDecreaseFromDistributionsIncludingJointVentures                   (655)ofc_MinorityInterestDecreaseFromDistributionsIncludingJointVentures
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
(655)ofc_MinorityInterestDecreaseFromDistributionsIncludingJointVentures
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
            (655)ofc_MinorityInterestDecreaseFromDistributionsIncludingJointVentures
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
       
COPT contribution to COPLP of distribution from subsidiary                       0ofc_GeneralPartnerContributionfromSubsidiaryDistribution
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
    1,608ofc_GeneralPartnerContributionfromSubsidiaryDistribution
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
      (1,608)ofc_GeneralPartnerContributionfromSubsidiaryDistribution
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
       
Adjustment to arrive at fair value of redeemable noncontrolling interest (3,955)ofc_AdjustmenttoEquitytoArriveatFairValueofRedeemableNoncontrollingInterest         (3,955)ofc_AdjustmenttoEquitytoArriveatFairValueofRedeemableNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
          (3,955)ofc_AdjustmenttoEquitytoArriveatFairValueofRedeemableNoncontrollingInterest
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
    (3,955)ofc_AdjustmenttoEquitytoArriveatFairValueofRedeemableNoncontrollingInterest
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
               
Tax benefit (loss) from share-based compensation 43us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation         43us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
          43us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
    43us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
               
Balance at Dec. 31, 2012 1,436,499us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest     333,833us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
809us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
1,653,672us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
    (617,455)us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedDistributionsInExcessOfNetIncomeMember
(5,435)us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedOtherComprehensiveIncomeMember
71,075us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
1,436,499us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
    1,089,391us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
    (5,708)us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedOtherComprehensiveIncomeMember
10,183us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
  8,800us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_LimitedPartnerMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
  333,833us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_GeneralPartnerMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
Balance (preferred units) at Dec. 31, 2012                                         352,000us-gaap_PreferredUnitsOutstanding
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_LimitedPartnerMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
  12,821,667us-gaap_PreferredUnitsOutstanding
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_GeneralPartnerMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
Balance (in units/ shares) at Dec. 31, 2012 80,952,986us-gaap_CommonStockSharesOutstanding                           85,020,528us-gaap_CommonStockSharesOutstanding
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
               
Increase (Decrease) in Shareholders' Equity                                              
Conversion of common units to common shares (234,246, 311,343 and 140,149 shares in 2012, 2013 and 2014, respectively) 0us-gaap_StockIssuedDuringPeriodValueConversionOfUnits       3us-gaap_StockIssuedDuringPeriodValueConversionOfUnits
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
3,994us-gaap_StockIssuedDuringPeriodValueConversionOfUnits
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
        (3,997)us-gaap_StockIssuedDuringPeriodValueConversionOfUnits
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
                       
Shares issued to the public (6,900,000 preferred shares in 2012, 8,625,000, 4,485,000 and 5,520,000 common shares in 2012, 2013 and 2014, respectively)(in dollars) 117,961us-gaap_StockIssuedDuringPeriodValueNewIssues       45us-gaap_StockIssuedDuringPeriodValueNewIssues
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
117,916us-gaap_StockIssuedDuringPeriodValueNewIssues
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
          117,961us-gaap_StockIssuedDuringPeriodValueNewIssues
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
    117,961us-gaap_StockIssuedDuringPeriodValueNewIssues
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
               
Shares issued to the public (in units/shares)         4,485,000us-gaap_StockIssuedDuringPeriodSharesNewIssues
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
                  4,485,000us-gaap_StockIssuedDuringPeriodSharesNewIssues
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
               
Stock redeemed or called during period (in units/ shares)       (3,390,000)us-gaap_StockRedeemedOrCalledDuringPeriodShares
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
                                    (3,390,000)us-gaap_StockRedeemedOrCalledDuringPeriodShares
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_GeneralPartnerMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
Redemption of preferred shares/units (2,200,000, 3,390,000 and 2,000,000 shares in 2012, 2013 and 2014, respectively) (84,750)us-gaap_StockRedeemedOrCalledDuringPeriodValue     (84,750)us-gaap_StockRedeemedOrCalledDuringPeriodValue
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
  2,904us-gaap_StockRedeemedOrCalledDuringPeriodValue
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
    (2,904)us-gaap_StockRedeemedOrCalledDuringPeriodValue
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedDistributionsInExcessOfNetIncomeMember
    (84,750)us-gaap_StockRedeemedOrCalledDuringPeriodValue
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
                    (84,750)us-gaap_StockRedeemedOrCalledDuringPeriodValue
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_GeneralPartnerMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
Issuance of common units resulting from common shares issued under at-the-market program (in units)                             1,500,000ofc_StockIssuedDuringPeriodSharesNewIssuesforOtherProgram
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
               
Issuance of common units resulting from common shares issued under at-the-market program (1,500,000 shares in 2013) (in dollars) 38,447ofc_StockIssuedDuringPeriodValueNewIssuesforOtherProgram       15ofc_StockIssuedDuringPeriodValueNewIssuesforOtherProgram
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
38,432ofc_StockIssuedDuringPeriodValueNewIssuesforOtherProgram
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
          38,447ofc_StockIssuedDuringPeriodValueNewIssuesforOtherProgram
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
    38,447ofc_StockIssuedDuringPeriodValueNewIssuesforOtherProgram
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
               
Acquisition of property and noncontrolling interest in other consolidated entity for COPLP common units 1,369ofc_NoncontrollingInterestIncreasefromSubsidiaryEquityIssuancePropertyandSubsidiaryNoncontrollingInterest         (1,296)ofc_NoncontrollingInterestIncreasefromSubsidiaryEquityIssuancePropertyandSubsidiaryNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
        2,665ofc_NoncontrollingInterestIncreasefromSubsidiaryEquityIssuancePropertyandSubsidiaryNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
                       
Acquisition of property and noncontrolling interest in other consolidated entity for COPLP common units (in units)                             221,501us-gaap_StockIssuedDuringPeriodSharesAcquisitions
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
               
Acquisition of property and noncontrolling interest in other consolidated entity for COPLP common units (in dollars)                       1,369us-gaap_StockIssuedDuringPeriodValueAcquisitions
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
    3,899us-gaap_StockIssuedDuringPeriodValueAcquisitions
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
      (2,530)us-gaap_StockIssuedDuringPeriodValueAcquisitions
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
       
Exercise of share options (in units/shares) 39,331us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised                           39,331us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
               
Exercise of share options ( 61,624, 39,331 and 62,888 shares in 2012, 2013 and 2014, respectively)(in dollars) 779us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised       0us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
779us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
          779us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
    779us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
               
Share-based compensation 7,605us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue       2us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
7,603us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
          7,605us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
    7,605us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
               
Share-based compensation (in shares/units)                             184,292us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
               
Restricted common units/shares redemptions (78,440)us-gaap_StockRepurchasedDuringPeriodShares                           (78,440)us-gaap_StockRepurchasedDuringPeriodShares
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
               
Restricted common units/shares redemptions (139,851, 78,440 and 57,537 shares in 2012, 2013 and 2014, respectively) (in dollars) (2,002)us-gaap_StockRepurchasedDuringPeriodValue         (2,002)us-gaap_StockRepurchasedDuringPeriodValue
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
          (2,002)us-gaap_StockRepurchasedDuringPeriodValue
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
    (2,002)us-gaap_StockRepurchasedDuringPeriodValue
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
               
Adjustments to noncontrolling interests resulting from changes in ownership of COPLP 0us-gaap_NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance         (744)us-gaap_NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
        744us-gaap_NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
                       
Comprehensive income (loss) 109,699ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments               93,707ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedDistributionsInExcessOfNetIncomeMember
8,915ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedOtherComprehensiveIncomeMember
7,077ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
109,699ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
    77,006ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
    9,313ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedOtherComprehensiveIncomeMember
2,749ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
  660ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_LimitedPartnerMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
  19,971ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_GeneralPartnerMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
Dividends/Distributions (115,216)us-gaap_Dividends               (115,216)us-gaap_Dividends
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedDistributionsInExcessOfNetIncomeMember
    (120,156)us-gaap_Dividends
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
    (99,525)us-gaap_Dividends
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
          (660)us-gaap_Dividends
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_LimitedPartnerMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
  (19,971)us-gaap_Dividends
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_GeneralPartnerMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
Distributions to owners of common and preferred units in COPLP (4,940)ofc_MinorityInterestDecreaseFromDistributionsToOperatingPartnershipNoncontrollingInterestHolders                   (4,940)ofc_MinorityInterestDecreaseFromDistributionsToOperatingPartnershipNoncontrollingInterestHolders
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
                       
Contributions from noncontrolling interests in other consolidates entities 86ofc_MinorityInterestIncreaseFromContributionsIncludingJointVentures         0ofc_MinorityInterestIncreaseFromContributionsIncludingJointVentures
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
        86ofc_MinorityInterestIncreaseFromContributionsIncludingJointVentures
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
86ofc_MinorityInterestIncreaseFromContributionsIncludingJointVentures
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
            86ofc_MinorityInterestIncreaseFromContributionsIncludingJointVentures
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
       
Distributions to noncontrolling interests (1,045)ofc_MinorityInterestDecreaseFromDistributionsIncludingJointVentures                   (1,045)ofc_MinorityInterestDecreaseFromDistributionsIncludingJointVentures
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
(1,045)ofc_MinorityInterestDecreaseFromDistributionsIncludingJointVentures
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
            (1,045)ofc_MinorityInterestDecreaseFromDistributionsIncludingJointVentures
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
       
Adjustment to arrive at fair value of redeemable noncontrolling interest (7,121)ofc_AdjustmenttoEquitytoArriveatFairValueofRedeemableNoncontrollingInterest         (7,121)ofc_AdjustmenttoEquitytoArriveatFairValueofRedeemableNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
          (7,121)ofc_AdjustmenttoEquitytoArriveatFairValueofRedeemableNoncontrollingInterest
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
    (7,121)ofc_AdjustmenttoEquitytoArriveatFairValueofRedeemableNoncontrollingInterest
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
               
Tax benefit (loss) from share-based compensation (122)us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation         (122)us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
          (122)us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
    (122)us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
               
Balance at Dec. 31, 2013 1,497,249us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest     249,083us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
874us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
1,814,015us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
    (641,868)us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedDistributionsInExcessOfNetIncomeMember
3,480us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedOtherComprehensiveIncomeMember
71,665us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
1,497,249us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
    1,226,318us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
    3,605us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedOtherComprehensiveIncomeMember
9,443us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
  8,800us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_LimitedPartnerMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
  249,083us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_GeneralPartnerMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
Balance (preferred units) at Dec. 31, 2013                                       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
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
9,431,667us-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
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
Balance (in units/ shares) at Dec. 31, 2013 87,394,512us-gaap_CommonStockSharesOutstanding                           91,372,212us-gaap_CommonStockSharesOutstanding
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
        3,977,700us-gaap_CommonStockSharesOutstanding
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_LimitedPartnerMember
  87,394,512us-gaap_CommonStockSharesOutstanding
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_GeneralPartnerMember
 
Increase (Decrease) in Shareholders' Equity                                              
Conversion of common units to common shares (234,246, 311,343 and 140,149 shares in 2012, 2013 and 2014, respectively) 0us-gaap_StockIssuedDuringPeriodValueConversionOfUnits       2us-gaap_StockIssuedDuringPeriodValueConversionOfUnits
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
1,841us-gaap_StockIssuedDuringPeriodValueConversionOfUnits
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
        (1,843)us-gaap_StockIssuedDuringPeriodValueConversionOfUnits
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
                       
Shares issued to the public (6,900,000 preferred shares in 2012, 8,625,000, 4,485,000 and 5,520,000 common shares in 2012, 2013 and 2014, respectively)(in dollars) 148,666us-gaap_StockIssuedDuringPeriodValueNewIssues       55us-gaap_StockIssuedDuringPeriodValueNewIssues
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
148,611us-gaap_StockIssuedDuringPeriodValueNewIssues
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
          148,666us-gaap_StockIssuedDuringPeriodValueNewIssues
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
    148,666us-gaap_StockIssuedDuringPeriodValueNewIssues
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
               
Shares issued to the public (in units/shares)         5,520,000us-gaap_StockIssuedDuringPeriodSharesNewIssues
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
                  5,520,000us-gaap_StockIssuedDuringPeriodSharesNewIssues
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
               
Stock redeemed or called during period (in units/ shares)       (2,000,000)us-gaap_StockRedeemedOrCalledDuringPeriodShares
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
                                    (2,000,000)us-gaap_StockRedeemedOrCalledDuringPeriodShares
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_GeneralPartnerMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
Redemption of preferred shares/units (2,200,000, 3,390,000 and 2,000,000 shares in 2012, 2013 and 2014, respectively) (50,000)us-gaap_StockRedeemedOrCalledDuringPeriodValue     (50,000)us-gaap_StockRedeemedOrCalledDuringPeriodValue
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
  1,769us-gaap_StockRedeemedOrCalledDuringPeriodValue
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
    (1,769)us-gaap_StockRedeemedOrCalledDuringPeriodValue
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedDistributionsInExcessOfNetIncomeMember
    (50,000)us-gaap_StockRedeemedOrCalledDuringPeriodValue
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
                    (50,000)us-gaap_StockRedeemedOrCalledDuringPeriodValue
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_GeneralPartnerMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
Exercise of share options (in units/shares) 62,888us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised                           62,888us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
               
Exercise of share options ( 61,624, 39,331 and 62,888 shares in 2012, 2013 and 2014, respectively)(in dollars) 1,489us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised         1,489us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
          1,489us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
    1,489us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
               
Share-based compensation 7,050us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue       2us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
7,048us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
          7,050us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
    7,050us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
               
Share-based compensation (in shares/units)                             195,272us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
               
Restricted common units/shares redemptions (57,537)us-gaap_StockRepurchasedDuringPeriodShares                           (57,537)us-gaap_StockRepurchasedDuringPeriodShares
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
               
Restricted common units/shares redemptions (139,851, 78,440 and 57,537 shares in 2012, 2013 and 2014, respectively) (in dollars) (1,554)us-gaap_StockRepurchasedDuringPeriodValue         (1,554)us-gaap_StockRepurchasedDuringPeriodValue
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
          (1,554)us-gaap_StockRepurchasedDuringPeriodValue
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
    (1,554)us-gaap_StockRepurchasedDuringPeriodValue
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
               
Adjustments to noncontrolling interests resulting from changes in ownership of COPLP 0us-gaap_NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance         (3,382)us-gaap_NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
        3,382us-gaap_NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
                       
Comprehensive income (loss) 38,274ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments               40,255ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedDistributionsInExcessOfNetIncomeMember
(4,777)ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedOtherComprehensiveIncomeMember
2,796ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
38,274ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
    25,331ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
    (4,986)ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedOtherComprehensiveIncomeMember
1,330ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
  660ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_LimitedPartnerMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
  15,939ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_GeneralPartnerMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
Dividends/Distributions (113,882)us-gaap_Dividends               (113,882)us-gaap_Dividends
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedDistributionsInExcessOfNetIncomeMember
    (118,811)us-gaap_Dividends
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
    (102,212)us-gaap_Dividends
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
          (660)us-gaap_Dividends
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_LimitedPartnerMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
  (15,939)us-gaap_Dividends
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_GeneralPartnerMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
Distributions to owners of common and preferred units in COPLP (4,929)ofc_MinorityInterestDecreaseFromDistributionsToOperatingPartnershipNoncontrollingInterestHolders                   (4,929)ofc_MinorityInterestDecreaseFromDistributionsToOperatingPartnershipNoncontrollingInterestHolders
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
                       
Contributions from noncontrolling interests in other consolidates entities 3ofc_MinorityInterestIncreaseFromContributionsIncludingJointVentures                   3ofc_MinorityInterestIncreaseFromContributionsIncludingJointVentures
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
3ofc_MinorityInterestIncreaseFromContributionsIncludingJointVentures
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
            3ofc_MinorityInterestIncreaseFromContributionsIncludingJointVentures
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
       
Distributions to noncontrolling interests (1,613)ofc_MinorityInterestDecreaseFromDistributionsIncludingJointVentures                   (1,613)ofc_MinorityInterestDecreaseFromDistributionsIncludingJointVentures
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
(1,613)ofc_MinorityInterestDecreaseFromDistributionsIncludingJointVentures
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
            (1,613)ofc_MinorityInterestDecreaseFromDistributionsIncludingJointVentures
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
       
Adjustment to arrive at fair value of redeemable noncontrolling interest 134ofc_AdjustmenttoEquitytoArriveatFairValueofRedeemableNoncontrollingInterest         134ofc_AdjustmenttoEquitytoArriveatFairValueofRedeemableNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
          134ofc_AdjustmenttoEquitytoArriveatFairValueofRedeemableNoncontrollingInterest
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
    134ofc_AdjustmenttoEquitytoArriveatFairValueofRedeemableNoncontrollingInterest
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
               
Tax benefit (loss) from share-based compensation (3)us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation         (3)us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
          (3)us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
    (3)us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
               
Balance at Dec. 31, 2014 $ 1,520,884us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest     $ 199,083us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
$ 933us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
$ 1,969,968us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
    $ (717,264)us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedDistributionsInExcessOfNetIncomeMember
$ (1,297)us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedOtherComprehensiveIncomeMember
$ 69,461us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
$ 1,520,884us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
    $ 1,305,219us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
    $ (1,381)us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedOtherComprehensiveIncomeMember
$ 9,163us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
  $ 8,800us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_LimitedPartnerMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
  $ 199,083us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_GeneralPartnerMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
Balance (preferred units) at Dec. 31, 2014                                       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
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
7,431,667us-gaap_PreferredUnitsOutstanding
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_GeneralPartnerMember
7,431,667us-gaap_PreferredUnitsOutstanding
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_GeneralPartnerMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PreferredStockMember
Balance (in units/ shares) at Dec. 31, 2014 93,255,284us-gaap_CommonStockSharesOutstanding                           97,092,835us-gaap_CommonStockSharesOutstanding
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
        3,837,551us-gaap_CommonStockSharesOutstanding
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_LimitedPartnerMember
  93,255,284us-gaap_CommonStockSharesOutstanding
/ dei_LegalEntityAxis
= us-gaap_SubsidiariesMember
/ us-gaap_PartnerTypeOfPartnersCapitalAccountAxis
= us-gaap_GeneralPartnerMember