XML 79 R50.htm IDEA: XBRL DOCUMENT
v3.6.0.2

Organization (Details) ft² in Thousands | Dec. 31, 2016 a ft² Property MW
--- | ---
Properties under redevelopment [Member] |
Investments in real estate |
Number of real estate properties | 3
Square footage of real estate properties (in square feet) | ft² | 104
Operating office properties [Member] |
Investments in real estate |
Number of real estate properties | 164
Square footage of real estate properties (in square feet) | ft² | 17,200
Operating office properties [Member] | Single-tenant data centers [Member] |
Investments in real estate |
Number of real estate properties | 13
Office properties under, or contractually committed for, construction or approved for redevelopment [Member] |
Investments in real estate |
Number of real estate properties | 11
Square footage of real estate properties (in square feet) | ft² | 1,400
Office properties under, or contractually committed for, construction or approved for redevelopment [Member] | Properties completed Held-for-future lease [Member] |
Investments in real estate |
Number of real estate properties | 2
Partially operational properties [Member] | Properties under redevelopment [Member] |
Investments in real estate |
Number of real estate properties | 3
Land controlled for future development [Member] |
Investments in real estate |
Square footage of real estate properties (in square feet) | a | 1,028
Developable square footage of real estate properties (in square feet) | ft² | 12,200
Other land [Member] |
Investments in real estate |
Square footage of real estate properties (in square feet) | a | 199
Operating wholesale data centers [Member] |
Investments in real estate |
Critical load (in MW's) | MW | 19.25
GI-COPT [Member] | Operating office properties [Member] | Single-tenant data centers [Member] |
Investments in real estate |
Number of real estate properties | 6

X
- Definition Represents the amount of the critical load of the property. Critical load is the amount of megawatts of power made available for the exclusive use tenants in the property. + References No definition available. + Details
Name: | ofc_CriticalLoad
Namespace Prefix: | ofc_
Data Type: | num:powerItemType
Balance Type: | na
Period Type: | instant

X
- Definition The amount of square feet into which a land parcel is potentially developable. + References No definition available. + Details
Name: | ofc_DevelopableSquareFeet
Namespace Prefix: | ofc_
Data Type: | num:areaItemType
Balance Type: | na
Period Type: | instant

X
- Definition Area of a real estate property. + References No definition available. + Details
Name: | us-gaap_AreaOfRealEstateProperty
Namespace Prefix: | us-gaap_
Data Type: | num:areaItemType
Balance Type: | na
Period Type: | instant

X
- Definition The number of real estate properties owned as of the balance sheet date. + References No definition available. + Details
Name: | us-gaap_NumberOfRealEstateProperties
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_RealEstatePropertiesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_RealEstatePropertiesAxis=ofc_PropertiesUnderorApprovedforRedevelopmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ofc_RealEstatePropertiesStatusAxis=ofc_OperatingOfficePropertiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstatePropertiesAxis=ofc_SingletenantDataCentersMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ofc_RealEstatePropertiesStatusAxis=ofc_OfficePropertiesUnderConstructionRedevelopmentOrContractuallyCommittedForConstructionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstatePropertiesAxis=ofc_PropertiesCompletedHeldforFutureLeaseMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ofc_RealEstatePropertiesStatusAxis=ofc_PartiallyOperationalPropertiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ofc_RealEstatePropertiesStatusAxis=ofc_LandControlledforFutureDevelopmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ofc_RealEstatePropertiesStatusAxis=ofc_OtherLandMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ofc_RealEstatePropertiesStatusAxis=ofc_WholesaleDataCenterMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=ofc_GICOPTDCPartnershipLLCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |