XML 68 R47.htm IDEA: XBRL DOCUMENT
v3.20.4

Organization (Narrative) (Details) ft² in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2020 property | Dec. 31, 2019 | Dec. 31, 2020 ft² | Dec. 31, 2020 MW | Dec. 31, 2020 a | Dec. 31, 2020 shares
Corporate Office Properties, L.P | COPT | Preferred units |  |  |  |  |  |
Investments in real estate |  |  |  |  |  |
Limited partners' capital account, units outstanding (in shares) | shares |  |  |  |  |  | 0
Common Units | Corporate Office Properties, L.P | COPT |  |  |  |  |  |
Investments in real estate |  |  |  |  |  |
Percentage ownership in operating partnership | 98.60% | 98.70% |  |  |  |
Operating properties |  |  |  |  |  |
Investments in real estate |  |  |  |  |  |
Number of real estate properties | 181 |  |  |  |  |
Area of real estate property (in sqft or acres) | ft² |  |  | 21.0 |  |  |
Operating properties | Office Properties |  |  |  |  |  |
Investments in real estate |  |  |  |  |  |
Number of real estate properties | 155 |  |  |  |  |
Area of real estate property (in sqft or acres) | ft² |  |  | 16.2 |  |  |
Operating properties | Single-tenant data centers |  |  |  |  |  |
Investments in real estate |  |  |  |  |  |
Number of real estate properties | 26 |  |  |  |  |
Area of real estate property (in sqft or acres) | ft² |  |  | 4.7 |  |  |
Operating Wholesale Data Center |  |  |  |  |  |
Investments in real estate |  |  |  |  |  |
Critical load (in megawatts) | MW |  |  |  | 19.25 |  |
Properties under development |  |  |  |  |  |
Investments in real estate |  |  |  |  |  |
Number of real estate properties | 11 |  |  |  |  |
Area of real estate property (in sqft or acres) | ft² |  |  | 1.5 |  |  |
Properties under development | Office Properties |  |  |  |  |  |
Investments in real estate |  |  |  |  |  |
Number of real estate properties | 9 |  |  |  |  |
Properties under development | Single-tenant data centers |  |  |  |  |  |
Investments in real estate |  |  |  |  |  |
Number of real estate properties | 2 |  |  |  |  |
Properties Under Development, Partially-Operational |  |  |  |  |  |
Investments in real estate |  |  |  |  |  |
Number of real estate properties | 3 |  |  |  |  |
Land controlled for future development |  |  |  |  |  |
Investments in real estate |  |  |  |  |  |
Area of real estate property (in sqft or acres) |  |  | 10.4 |  | 830 |
Other land |  |  |  |  |  |
Investments in real estate |  |  |  |  |  |
Area of real estate property (in sqft or acres) | a |  |  |  |  | 43 |
Unconsolidated Real Estate Joint Ventures |  |  |  |  |  |
Investments in real estate |  |  |  |  |  |
Number of real estate properties | 17 |  |  |  |  |
Unconsolidated Real Estate Joint Ventures | Operating properties | Single-tenant data centers |  |  |  |  |  |
Investments in real estate |  |  |  |  |  |
Number of real estate properties | 17 |  |  |  |  |

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 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 Percentage investment held by the managing member or general partner of the limited liability company (LLC) or limited partnership (LP). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 272 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6373374&loc=d3e70478-108055 + Details
Name: | us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerOwnershipInterest
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The number of limited partner units outstanding. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 5 -Subparagraph (SAB Topic 4.F) -URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187171-122770 + Details
Name: | us-gaap_LimitedPartnersCapitalAccountUnitsOutstanding
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
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: | srt_ConsolidatedEntitiesAxis=srt_SubsidiariesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_OwnershipAxis=ofc_COPTMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=us-gaap_PreferredStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ofc_UnitsByNameAxis=ofc_CommonUnitsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

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

X
- Details
Name: | ofc_RealEstatePropertiesStatusAxis=ofc_PropertiesUnderDevelopmentPartiallyOperationalMember
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: | srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=ofc_UnconsolidatedRealEstateJointVenturesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |