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v2.4.1.9

Properties, net (Details 4) (USD $) In Millions, unless otherwise specified | 12 Months Ended
--- | ---
Dec. 31, 2014 sqft Property | Dec. 31, 2013 Property sqft
Newly-constructed properties placed in service |  |
Construction and Redevelopment Activities |  |
Square Feet of Properties Placed in Service | 692,000 ofc_SquareFeetofPropertiesPlacedinService / us-gaap_RealEstatePropertiesAxis = ofc_NewlyConstructedPropertiesPlacedInServiceMember | 812,000 ofc_SquareFeetofPropertiesPlacedinService / us-gaap_RealEstatePropertiesAxis = ofc_NewlyConstructedPropertiesPlacedInServiceMember
Number of Real Estate Properties Placed In Service | 5 ofc_NumberOfRealEstatePropertiesPlacedInService / us-gaap_RealEstatePropertiesAxis = ofc_NewlyConstructedPropertiesPlacedInServiceMember | 8 ofc_NumberOfRealEstatePropertiesPlacedInService / us-gaap_RealEstatePropertiesAxis = ofc_NewlyConstructedPropertiesPlacedInServiceMember
Properties under construction or contractually committed for construction |  |
Construction and Redevelopment Activities |  |
Number of real estate properties | 8 us-gaap_NumberOfRealEstateProperties / us-gaap_RealEstatePropertiesAxis = ofc_PropertiesUnderConstructionOrContractuallyCommitedForConstructionMember |
Square footage of real estate properties (in square feet) | 1,200,000 us-gaap_AreaOfRealEstateProperty / us-gaap_RealEstatePropertiesAxis = ofc_PropertiesUnderConstructionOrContractuallyCommitedForConstructionMember |
Properties under construction or contractually committed for construction | Northern Virginia |  |
Construction and Redevelopment Activities |  |
Number of real estate properties | 4 us-gaap_NumberOfRealEstateProperties / us-gaap_RealEstatePropertiesAxis = ofc_PropertiesUnderConstructionOrContractuallyCommitedForConstructionMember / ofc_RealEstatePropertyLocationAxis = ofc_NorthernVirginiaMember |
Properties under construction or contractually committed for construction | Baltimore and Washington Corridor |  |
Construction and Redevelopment Activities |  |
Number of real estate properties | 2 us-gaap_NumberOfRealEstateProperties / us-gaap_RealEstatePropertiesAxis = ofc_PropertiesUnderConstructionOrContractuallyCommitedForConstructionMember / ofc_RealEstatePropertyLocationAxis = ofc_BaltimoreAndWashingtonCorridorMember |
Properties under construction or contractually committed for construction | Huntsville |  |
Construction and Redevelopment Activities |  |
Number of real estate properties | 1 us-gaap_NumberOfRealEstateProperties / us-gaap_RealEstatePropertiesAxis = ofc_PropertiesUnderConstructionOrContractuallyCommitedForConstructionMember / ofc_RealEstatePropertyLocationAxis = ofc_HuntsvilleMember |
Properties under construction or contractually committed for construction | San Antonio |  |
Construction and Redevelopment Activities |  |
Number of real estate properties | 1 us-gaap_NumberOfRealEstateProperties / us-gaap_RealEstatePropertiesAxis = ofc_PropertiesUnderConstructionOrContractuallyCommitedForConstructionMember / ofc_RealEstatePropertyLocationAxis = ofc_SanAntonioMember |
Properties under redevelopment |  |
Construction and Redevelopment Activities |  |
Number of real estate properties | 5 us-gaap_NumberOfRealEstateProperties / us-gaap_RealEstatePropertiesAxis = ofc_PropertiesUnderorApprovedforRedevelopmentMember |
Square footage of real estate properties (in square feet) | 344,000 us-gaap_AreaOfRealEstateProperty / us-gaap_RealEstatePropertiesAxis = ofc_PropertiesUnderorApprovedforRedevelopmentMember |
Properties under redevelopment | Baltimore and Washington Corridor |  |
Construction and Redevelopment Activities |  |
Number of real estate properties | 3 us-gaap_NumberOfRealEstateProperties / us-gaap_RealEstatePropertiesAxis = ofc_PropertiesUnderorApprovedforRedevelopmentMember / ofc_RealEstatePropertyLocationAxis = ofc_BaltimoreAndWashingtonCorridorMember |
Properties under redevelopment | Greater Philadelphia |  |
Construction and Redevelopment Activities |  |
Number of real estate properties | 1 us-gaap_NumberOfRealEstateProperties / us-gaap_RealEstatePropertiesAxis = ofc_PropertiesUnderorApprovedforRedevelopmentMember / ofc_RealEstatePropertyLocationAxis = ofc_GreaterPhiladelphiaMember |
Properties under redevelopment | St Marys County |  |
Construction and Redevelopment Activities |  |
Number of real estate properties | 1 us-gaap_NumberOfRealEstateProperties / us-gaap_RealEstatePropertiesAxis = ofc_PropertiesUnderorApprovedforRedevelopmentMember / ofc_RealEstatePropertyLocationAxis = ofc_StMarysCountyMember |
Greater Philadelphia |  |
Construction and Redevelopment Activities |  |
Depreciation Expense Resulting From Useful Life Change | 12.9 ofc_DepreciationExpenseResultingFromUsefulLifeChange / us-gaap_StatementGeographicalAxis = ofc_GreaterPhiladelphiaMember |

X
- Definition Additional depreciation expense recognized resulting from a change in the useful life of the disclosed asset. + References No definition available. + Details
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Balance Type: | debit
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- Definition Represents the number of real estate properties placed in service during the year. + References No definition available. + Details
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Namespace Prefix: | ofc_
Data Type: | xbrli:integerItemType
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- Definition The amount of square footage placed into service during the period. + References No definition available. + Details
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Namespace Prefix: | ofc_
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- Definition Area of a real estate property. + References No definition available. + Details
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- Details
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- Definition The number of real estate properties owned as of the balance sheet date. + References No definition available. + Details
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- Details
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- Details
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Period Type: |