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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 ($) | Corporate Office Properties, L.P. General Partner | Corporate Office Properties, L.P. General Partner Preferred Shares USD ($)
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Balance at Dec. 31, 2011 | $ 1,205,899 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest |  |  | $ 216,333 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest / us-gaap_StatementEquityComponentsAxis = us-gaap_PreferredStockMember | $ 720 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest / us-gaap_StatementEquityComponentsAxis = us-gaap_CommonStockMember | $ 1,451,078 us-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 | $ 73,542 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest / us-gaap_StatementEquityComponentsAxis = us-gaap_NoncontrollingInterestMember | $ 1,205,899 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  | $ 972,107 us-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 | $ 10,496 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_StatementEquityComponentsAxis = us-gaap_NoncontrollingInterestMember |  | $ 8,800 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_PartnerTypeOfPartnersCapitalAccountAxis = us-gaap_LimitedPartnerMember / us-gaap_StatementEquityComponentsAxis = us-gaap_PreferredStockMember |  | $ 216,333 us-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 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 352,000 us-gaap_PreferredUnitsOutstanding / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_PartnerTypeOfPartnersCapitalAccountAxis = us-gaap_LimitedPartnerMember / us-gaap_StatementEquityComponentsAxis = us-gaap_PreferredStockMember |  | 8,121,667 us-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 | 72,011,324 us-gaap_CommonStockSharesOutstanding |  |  |  |  |  |  |  |  |  |  |  |  |  | 76,313,112 us-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) | 0 us-gaap_StockIssuedDuringPeriodValueConversionOfUnits |  |  |  | 2 us-gaap_StockIssuedDuringPeriodValueConversionOfUnits / us-gaap_StatementEquityComponentsAxis = us-gaap_CommonStockMember | 2,812 us-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) |  | 165,652 us-gaap_StockIssuedDuringPeriodValueNewIssues / us-gaap_StatementClassOfStockAxis = us-gaap_PreferredStockMember | 204,696 us-gaap_StockIssuedDuringPeriodValueNewIssues / us-gaap_StatementClassOfStockAxis = us-gaap_CommonStockMember | 172,500 us-gaap_StockIssuedDuringPeriodValueNewIssues / us-gaap_StatementEquityComponentsAxis = us-gaap_PreferredStockMember | 86 us-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 | 204,610 us-gaap_StockIssuedDuringPeriodValueNewIssues / us-gaap_StatementClassOfStockAxis = us-gaap_CommonStockMember / us-gaap_StatementEquityComponentsAxis = us-gaap_AdditionalPaidInCapitalMember |  |  |  |  | 165,652 us-gaap_StockIssuedDuringPeriodValueNewIssues / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_StatementClassOfStockAxis = us-gaap_PreferredStockMember | 204,696 us-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 | 204,696 us-gaap_StockIssuedDuringPeriodValueNewIssues / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_StatementClassOfStockAxis = us-gaap_CommonStockMember / us-gaap_StatementEquityComponentsAxis = us-gaap_CommonStockMember |  |  |  |  |  | 172,500 us-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) |  |  |  | 6,900,000 us-gaap_StockIssuedDuringPeriodSharesNewIssues / us-gaap_StatementEquityComponentsAxis = us-gaap_PreferredStockMember | 8,625,000 us-gaap_StockIssuedDuringPeriodSharesNewIssues / us-gaap_StatementEquityComponentsAxis = us-gaap_CommonStockMember |  |  |  |  |  |  |  |  |  | 8,625,000 us-gaap_StockIssuedDuringPeriodSharesNewIssues / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_StatementEquityComponentsAxis = us-gaap_CommonStockMember |  |  |  |  |  |  |  | 6,900,000 us-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 |  | 1,827 us-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) | 61,624 us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised |  |  |  |  |  |  |  |  |  |  |  |  |  | 61,624 us-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) | 928 us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised |  |  |  | 0 us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised / us-gaap_StatementEquityComponentsAxis = us-gaap_CommonStockMember | 928 us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised / us-gaap_StatementEquityComponentsAxis = us-gaap_AdditionalPaidInCapitalMember |  |  |  |  |  | 928 us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  | 928 us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_StatementEquityComponentsAxis = us-gaap_CommonStockMember |  |  |  |  |  |  |  |
Share-based compensation | 11,184 us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue |  |  |  | 1 us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue / us-gaap_StatementEquityComponentsAxis = us-gaap_CommonStockMember | 11,183 us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue / us-gaap_StatementEquityComponentsAxis = us-gaap_AdditionalPaidInCapitalMember |  |  |  |  |  | 11,184 us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  | 11,184 us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_StatementEquityComponentsAxis = us-gaap_CommonStockMember |  |  |  |  |  |  |  |
Share-based compensation (in shares/units) |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 160,643 us-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 | 0 us-gaap_NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance |  |  |  |  | (4,627)us-gaap_NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance / us-gaap_StatementEquityComponentsAxis = us-gaap_AdditionalPaidInCapitalMember |  |  |  |  | 4,627 us-gaap_NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance / us-gaap_StatementEquityComponentsAxis = us-gaap_NoncontrollingInterestMember |  |  |  |  |  |  |  |  |  |  |  |
Comprehensive income (loss) | 18,927 ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments |  |  |  |  |  |  |  | 20,977 ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments / us-gaap_StatementEquityComponentsAxis = us-gaap_AccumulatedDistributionsInExcessOfNetIncomeMember | (3,702)ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments / us-gaap_StatementEquityComponentsAxis = us-gaap_AccumulatedOtherComprehensiveIncomeMember | 1,652 ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments / us-gaap_StatementEquityComponentsAxis = us-gaap_NoncontrollingInterestMember | 18,927 ofc_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 | 1,950 ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_StatementEquityComponentsAxis = us-gaap_NoncontrollingInterestMember |  | 660 ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_PartnerTypeOfPartnersCapitalAccountAxis = us-gaap_LimitedPartnerMember / us-gaap_StatementEquityComponentsAxis = us-gaap_PreferredStockMember |  | 20,844 ofc_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 |  |  |  |  |  |  |  |  |  |  |  | 0 ofc_GeneralPartnerContributionfromSubsidiaryDistribution / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  | 1,608 ofc_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 | 43 us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation |  |  |  |  | 43 us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation / us-gaap_StatementEquityComponentsAxis = us-gaap_AdditionalPaidInCapitalMember |  |  |  |  |  | 43 us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  | 43 us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_StatementEquityComponentsAxis = us-gaap_CommonStockMember |  |  |  |  |  |  |  |
Balance at Dec. 31, 2012 | 1,436,499 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest |  |  | 333,833 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest / us-gaap_StatementEquityComponentsAxis = us-gaap_PreferredStockMember | 809 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest / us-gaap_StatementEquityComponentsAxis = us-gaap_CommonStockMember | 1,653,672 us-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 | 71,075 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest / us-gaap_StatementEquityComponentsAxis = us-gaap_NoncontrollingInterestMember | 1,436,499 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  | 1,089,391 us-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 | 10,183 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_StatementEquityComponentsAxis = us-gaap_NoncontrollingInterestMember |  | 8,800 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_PartnerTypeOfPartnersCapitalAccountAxis = us-gaap_LimitedPartnerMember / us-gaap_StatementEquityComponentsAxis = us-gaap_PreferredStockMember |  | 333,833 us-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 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 352,000 us-gaap_PreferredUnitsOutstanding / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_PartnerTypeOfPartnersCapitalAccountAxis = us-gaap_LimitedPartnerMember / us-gaap_StatementEquityComponentsAxis = us-gaap_PreferredStockMember |  | 12,821,667 us-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 | 80,952,986 us-gaap_CommonStockSharesOutstanding |  |  |  |  |  |  |  |  |  |  |  |  |  | 85,020,528 us-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) | 0 us-gaap_StockIssuedDuringPeriodValueConversionOfUnits |  |  |  | 3 us-gaap_StockIssuedDuringPeriodValueConversionOfUnits / us-gaap_StatementEquityComponentsAxis = us-gaap_CommonStockMember | 3,994 us-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) | 117,961 us-gaap_StockIssuedDuringPeriodValueNewIssues |  |  |  | 45 us-gaap_StockIssuedDuringPeriodValueNewIssues / us-gaap_StatementEquityComponentsAxis = us-gaap_CommonStockMember | 117,916 us-gaap_StockIssuedDuringPeriodValueNewIssues / us-gaap_StatementEquityComponentsAxis = us-gaap_AdditionalPaidInCapitalMember |  |  |  |  |  | 117,961 us-gaap_StockIssuedDuringPeriodValueNewIssues / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  | 117,961 us-gaap_StockIssuedDuringPeriodValueNewIssues / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_StatementEquityComponentsAxis = us-gaap_CommonStockMember |  |  |  |  |  |  |  |
Shares issued to the public (in units/shares) |  |  |  |  | 4,485,000 us-gaap_StockIssuedDuringPeriodSharesNewIssues / us-gaap_StatementEquityComponentsAxis = us-gaap_CommonStockMember |  |  |  |  |  |  |  |  |  | 4,485,000 us-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 |  | 2,904 us-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) |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 1,500,000 ofc_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) | 38,447 ofc_StockIssuedDuringPeriodValueNewIssuesforOtherProgram |  |  |  | 15 ofc_StockIssuedDuringPeriodValueNewIssuesforOtherProgram / us-gaap_StatementEquityComponentsAxis = us-gaap_CommonStockMember | 38,432 ofc_StockIssuedDuringPeriodValueNewIssuesforOtherProgram / us-gaap_StatementEquityComponentsAxis = us-gaap_AdditionalPaidInCapitalMember |  |  |  |  |  | 38,447 ofc_StockIssuedDuringPeriodValueNewIssuesforOtherProgram / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  | 38,447 ofc_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 | 1,369 ofc_NoncontrollingInterestIncreasefromSubsidiaryEquityIssuancePropertyandSubsidiaryNoncontrollingInterest |  |  |  |  | (1,296)ofc_NoncontrollingInterestIncreasefromSubsidiaryEquityIssuancePropertyandSubsidiaryNoncontrollingInterest / us-gaap_StatementEquityComponentsAxis = us-gaap_AdditionalPaidInCapitalMember |  |  |  |  | 2,665 ofc_NoncontrollingInterestIncreasefromSubsidiaryEquityIssuancePropertyandSubsidiaryNoncontrollingInterest / us-gaap_StatementEquityComponentsAxis = us-gaap_NoncontrollingInterestMember |  |  |  |  |  |  |  |  |  |  |  |
Acquisition of property and noncontrolling interest in other consolidated entity for COPLP common units (in units) |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 221,501 us-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) |  |  |  |  |  |  |  |  |  |  |  | 1,369 us-gaap_StockIssuedDuringPeriodValueAcquisitions / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  | 3,899 us-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) | 39,331 us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised |  |  |  |  |  |  |  |  |  |  |  |  |  | 39,331 us-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) | 779 us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised |  |  |  | 0 us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised / us-gaap_StatementEquityComponentsAxis = us-gaap_CommonStockMember | 779 us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised / us-gaap_StatementEquityComponentsAxis = us-gaap_AdditionalPaidInCapitalMember |  |  |  |  |  | 779 us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  | 779 us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_StatementEquityComponentsAxis = us-gaap_CommonStockMember |  |  |  |  |  |  |  |
Share-based compensation | 7,605 us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue |  |  |  | 2 us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue / us-gaap_StatementEquityComponentsAxis = us-gaap_CommonStockMember | 7,603 us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue / us-gaap_StatementEquityComponentsAxis = us-gaap_AdditionalPaidInCapitalMember |  |  |  |  |  | 7,605 us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  | 7,605 us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_StatementEquityComponentsAxis = us-gaap_CommonStockMember |  |  |  |  |  |  |  |
Share-based compensation (in shares/units) |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 184,292 us-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 | 0 us-gaap_NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance |  |  |  |  | (744)us-gaap_NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance / us-gaap_StatementEquityComponentsAxis = us-gaap_AdditionalPaidInCapitalMember |  |  |  |  | 744 us-gaap_NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance / us-gaap_StatementEquityComponentsAxis = us-gaap_NoncontrollingInterestMember |  |  |  |  |  |  |  |  |  |  |  |
Comprehensive income (loss) | 109,699 ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments |  |  |  |  |  |  |  | 93,707 ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments / us-gaap_StatementEquityComponentsAxis = us-gaap_AccumulatedDistributionsInExcessOfNetIncomeMember | 8,915 ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments / us-gaap_StatementEquityComponentsAxis = us-gaap_AccumulatedOtherComprehensiveIncomeMember | 7,077 ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments / us-gaap_StatementEquityComponentsAxis = us-gaap_NoncontrollingInterestMember | 109,699 ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  | 77,006 ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_StatementEquityComponentsAxis = us-gaap_CommonStockMember |  |  | 9,313 ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_StatementEquityComponentsAxis = us-gaap_AccumulatedOtherComprehensiveIncomeMember | 2,749 ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_StatementEquityComponentsAxis = us-gaap_NoncontrollingInterestMember |  | 660 ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_PartnerTypeOfPartnersCapitalAccountAxis = us-gaap_LimitedPartnerMember / us-gaap_StatementEquityComponentsAxis = us-gaap_PreferredStockMember |  | 19,971 ofc_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 | 86 ofc_MinorityInterestIncreaseFromContributionsIncludingJointVentures |  |  |  |  | 0 ofc_MinorityInterestIncreaseFromContributionsIncludingJointVentures / us-gaap_StatementEquityComponentsAxis = us-gaap_AdditionalPaidInCapitalMember |  |  |  |  | 86 ofc_MinorityInterestIncreaseFromContributionsIncludingJointVentures / us-gaap_StatementEquityComponentsAxis = us-gaap_NoncontrollingInterestMember | 86 ofc_MinorityInterestIncreaseFromContributionsIncludingJointVentures / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |  |  |  |  | 86 ofc_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 | 1,497,249 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest |  |  | 249,083 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest / us-gaap_StatementEquityComponentsAxis = us-gaap_PreferredStockMember | 874 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest / us-gaap_StatementEquityComponentsAxis = us-gaap_CommonStockMember | 1,814,015 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest / us-gaap_StatementEquityComponentsAxis = us-gaap_AdditionalPaidInCapitalMember |  |  | (641,868)us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest / us-gaap_StatementEquityComponentsAxis = us-gaap_AccumulatedDistributionsInExcessOfNetIncomeMember | 3,480 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest / us-gaap_StatementEquityComponentsAxis = us-gaap_AccumulatedOtherComprehensiveIncomeMember | 71,665 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest / us-gaap_StatementEquityComponentsAxis = us-gaap_NoncontrollingInterestMember | 1,497,249 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  | 1,226,318 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_StatementEquityComponentsAxis = us-gaap_CommonStockMember |  |  | 3,605 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_StatementEquityComponentsAxis = us-gaap_AccumulatedOtherComprehensiveIncomeMember | 9,443 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_StatementEquityComponentsAxis = us-gaap_NoncontrollingInterestMember |  | 8,800 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_PartnerTypeOfPartnersCapitalAccountAxis = us-gaap_LimitedPartnerMember / us-gaap_StatementEquityComponentsAxis = us-gaap_PreferredStockMember |  | 249,083 us-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 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 352,000 us-gaap_PreferredUnitsOutstanding / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_PartnerTypeOfPartnersCapitalAccountAxis = us-gaap_LimitedPartnerMember | 352,000 us-gaap_PreferredUnitsOutstanding / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_PartnerTypeOfPartnersCapitalAccountAxis = us-gaap_LimitedPartnerMember / us-gaap_StatementEquityComponentsAxis = us-gaap_PreferredStockMember | 9,431,667 us-gaap_PreferredUnitsOutstanding / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_PartnerTypeOfPartnersCapitalAccountAxis = us-gaap_GeneralPartnerMember | 9,431,667 us-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 | 87,394,512 us-gaap_CommonStockSharesOutstanding |  |  |  |  |  |  |  |  |  |  |  |  |  | 91,372,212 us-gaap_CommonStockSharesOutstanding / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_StatementEquityComponentsAxis = us-gaap_CommonStockMember |  |  |  |  | 3,977,700 us-gaap_CommonStockSharesOutstanding / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_PartnerTypeOfPartnersCapitalAccountAxis = us-gaap_LimitedPartnerMember |  | 87,394,512 us-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) | 0 us-gaap_StockIssuedDuringPeriodValueConversionOfUnits |  |  |  | 2 us-gaap_StockIssuedDuringPeriodValueConversionOfUnits / us-gaap_StatementEquityComponentsAxis = us-gaap_CommonStockMember | 1,841 us-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) | 148,666 us-gaap_StockIssuedDuringPeriodValueNewIssues |  |  |  | 55 us-gaap_StockIssuedDuringPeriodValueNewIssues / us-gaap_StatementEquityComponentsAxis = us-gaap_CommonStockMember | 148,611 us-gaap_StockIssuedDuringPeriodValueNewIssues / us-gaap_StatementEquityComponentsAxis = us-gaap_AdditionalPaidInCapitalMember |  |  |  |  |  | 148,666 us-gaap_StockIssuedDuringPeriodValueNewIssues / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  | 148,666 us-gaap_StockIssuedDuringPeriodValueNewIssues / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_StatementEquityComponentsAxis = us-gaap_CommonStockMember |  |  |  |  |  |  |  |
Shares issued to the public (in units/shares) |  |  |  |  | 5,520,000 us-gaap_StockIssuedDuringPeriodSharesNewIssues / us-gaap_StatementEquityComponentsAxis = us-gaap_CommonStockMember |  |  |  |  |  |  |  |  |  | 5,520,000 us-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 |  | 1,769 us-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) | 62,888 us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised |  |  |  |  |  |  |  |  |  |  |  |  |  | 62,888 us-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) | 1,489 us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised |  |  |  |  | 1,489 us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised / us-gaap_StatementEquityComponentsAxis = us-gaap_AdditionalPaidInCapitalMember |  |  |  |  |  | 1,489 us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  | 1,489 us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_StatementEquityComponentsAxis = us-gaap_CommonStockMember |  |  |  |  |  |  |  |
Share-based compensation | 7,050 us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue |  |  |  | 2 us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue / us-gaap_StatementEquityComponentsAxis = us-gaap_CommonStockMember | 7,048 us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue / us-gaap_StatementEquityComponentsAxis = us-gaap_AdditionalPaidInCapitalMember |  |  |  |  |  | 7,050 us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  | 7,050 us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_StatementEquityComponentsAxis = us-gaap_CommonStockMember |  |  |  |  |  |  |  |
Share-based compensation (in shares/units) |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 195,272 us-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 | 0 us-gaap_NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance |  |  |  |  | (3,382)us-gaap_NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance / us-gaap_StatementEquityComponentsAxis = us-gaap_AdditionalPaidInCapitalMember |  |  |  |  | 3,382 us-gaap_NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance / us-gaap_StatementEquityComponentsAxis = us-gaap_NoncontrollingInterestMember |  |  |  |  |  |  |  |  |  |  |  |
Comprehensive income (loss) | 38,274 ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments |  |  |  |  |  |  |  | 40,255 ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments / us-gaap_StatementEquityComponentsAxis = us-gaap_AccumulatedDistributionsInExcessOfNetIncomeMember | (4,777)ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments / us-gaap_StatementEquityComponentsAxis = us-gaap_AccumulatedOtherComprehensiveIncomeMember | 2,796 ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments / us-gaap_StatementEquityComponentsAxis = us-gaap_NoncontrollingInterestMember | 38,274 ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  | 25,331 ofc_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 | 1,330 ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_StatementEquityComponentsAxis = us-gaap_NoncontrollingInterestMember |  | 660 ofc_ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_PartnerTypeOfPartnersCapitalAccountAxis = us-gaap_LimitedPartnerMember / us-gaap_StatementEquityComponentsAxis = us-gaap_PreferredStockMember |  | 15,939 ofc_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 | 3 ofc_MinorityInterestIncreaseFromContributionsIncludingJointVentures |  |  |  |  |  |  |  |  |  | 3 ofc_MinorityInterestIncreaseFromContributionsIncludingJointVentures / us-gaap_StatementEquityComponentsAxis = us-gaap_NoncontrollingInterestMember | 3 ofc_MinorityInterestIncreaseFromContributionsIncludingJointVentures / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |  |  |  |  | 3 ofc_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 | 134 ofc_AdjustmenttoEquitytoArriveatFairValueofRedeemableNoncontrollingInterest |  |  |  |  | 134 ofc_AdjustmenttoEquitytoArriveatFairValueofRedeemableNoncontrollingInterest / us-gaap_StatementEquityComponentsAxis = us-gaap_AdditionalPaidInCapitalMember |  |  |  |  |  | 134 ofc_AdjustmenttoEquitytoArriveatFairValueofRedeemableNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  | 134 ofc_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 | $ 1,520,884 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest |  |  | $ 199,083 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest / us-gaap_StatementEquityComponentsAxis = us-gaap_PreferredStockMember | $ 933 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest / us-gaap_StatementEquityComponentsAxis = us-gaap_CommonStockMember | $ 1,969,968 us-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 | $ 69,461 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest / us-gaap_StatementEquityComponentsAxis = us-gaap_NoncontrollingInterestMember | $ 1,520,884 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  | $ 1,305,219 us-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 | $ 9,163 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_StatementEquityComponentsAxis = us-gaap_NoncontrollingInterestMember |  | $ 8,800 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_PartnerTypeOfPartnersCapitalAccountAxis = us-gaap_LimitedPartnerMember / us-gaap_StatementEquityComponentsAxis = us-gaap_PreferredStockMember |  | $ 199,083 us-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 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 352,000 us-gaap_PreferredUnitsOutstanding / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_PartnerTypeOfPartnersCapitalAccountAxis = us-gaap_LimitedPartnerMember | 352,000 us-gaap_PreferredUnitsOutstanding / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_PartnerTypeOfPartnersCapitalAccountAxis = us-gaap_LimitedPartnerMember / us-gaap_StatementEquityComponentsAxis = us-gaap_PreferredStockMember | 7,431,667 us-gaap_PreferredUnitsOutstanding / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_PartnerTypeOfPartnersCapitalAccountAxis = us-gaap_GeneralPartnerMember | 7,431,667 us-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 | 93,255,284 us-gaap_CommonStockSharesOutstanding |  |  |  |  |  |  |  |  |  |  |  |  |  | 97,092,835 us-gaap_CommonStockSharesOutstanding / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_StatementEquityComponentsAxis = us-gaap_CommonStockMember |  |  |  |  | 3,837,551 us-gaap_CommonStockSharesOutstanding / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_PartnerTypeOfPartnersCapitalAccountAxis = us-gaap_LimitedPartnerMember |  | 93,255,284 us-gaap_CommonStockSharesOutstanding / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_PartnerTypeOfPartnersCapitalAccountAxis = us-gaap_GeneralPartnerMember |

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