Annual report pursuant to Section 13 and 15(d)

Properties, net (Details 2)

v2.4.1.9
Properties, net (Details 2) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Properties    
Projects in development or held for future development $ 545,426us-gaap_DevelopmentInProcess $ 511,608us-gaap_DevelopmentInProcess
Projects in development or held for future development | Land in development or held for future development    
Properties    
Projects in development or held for future development 214,977us-gaap_DevelopmentInProcess
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= ofc_LandInDevelopmentOrHeldForFutureDevelopmentMember
/ ofc_RealEstatePropertiesStatusAxis
= ofc_ProjectsInDevelopmentOrHeldForFutureDevelopmentMember 		245,676us-gaap_DevelopmentInProcess
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= ofc_LandInDevelopmentOrHeldForFutureDevelopmentMember
/ ofc_RealEstatePropertiesStatusAxis
= ofc_ProjectsInDevelopmentOrHeldForFutureDevelopmentMember
Projects in development or held for future development | Construction in progress, excluding land    
Properties    
Projects in development or held for future development $ 330,449us-gaap_DevelopmentInProcess
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_ConstructionInProgressMember
/ ofc_RealEstatePropertiesStatusAxis
= ofc_ProjectsInDevelopmentOrHeldForFutureDevelopmentMember 		$ 265,932us-gaap_DevelopmentInProcess
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_ConstructionInProgressMember
/ ofc_RealEstatePropertiesStatusAxis
= ofc_ProjectsInDevelopmentOrHeldForFutureDevelopmentMember