COPT Defense Properties Quarterly report pursuant to Section 13 or 15(d)

Properties, net (Details 3)

Properties, net (Details 3)	6 Months Ended
Properties, net (Details 3)	Jun. 30, 2014 Property sqft
Newly constructed properties placed in service
Construction and Redevelopment Activities
Square Feet of Properties Placed in Service	457,000
Number of Real Estate Properties Placed In Service	3
Properties under construction or contractually committed for construction
Construction and Redevelopment Activities
Number of real estate properties	8
Square footage of real estate properties (in square feet)	1,100,000
Properties under construction or contractually committed for construction \| Baltimore and Washington Corridor
Construction and Redevelopment Activities
Number of real estate properties	3
Properties under construction or contractually committed for construction \| Northern Virginia
Construction and Redevelopment Activities
Number of real estate properties	3
Properties under construction or contractually committed for construction \| San Antonio
Construction and Redevelopment Activities
Number of real estate properties	1
Properties under construction or contractually committed for construction \| Huntsville
Construction and Redevelopment Activities
Number of real estate properties	1
Properties under or approved for redevelopment
Construction and Redevelopment Activities
Number of real estate properties	4
Square footage of real estate properties (in square feet)	276,000
Properties under or approved for redevelopment \| Baltimore and Washington Corridor
Construction and Redevelopment Activities
Number of real estate properties	2
Properties under or approved for redevelopment \| Greater Philadelphia
Construction and Redevelopment Activities
Number of real estate properties	1
Properties under or approved for redevelopment \| St Marys County
Construction and Redevelopment Activities
Number of real estate properties	1