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

Organization - Narrative 1 (Details)

Organization - Narrative 1 (Details) - Sep. 30, 2020 ft² in Millions	property	ft²	MW	a
Unconsolidated Real Estate Joint Ventures
Investments in real estate
Number of real estate properties	15
Operating Properties
Investments in real estate
Number of real estate properties	176
Area of real estate property (in sqft or acres) \| ft²		20.4
Operating Properties \| Office Properties
Investments in real estate
Number of real estate properties	151
Area of real estate property (in sqft or acres) \| ft²		15.9
Operating Properties \| Single-tenant data centers
Investments in real estate
Number of real estate properties	25
Area of real estate property (in sqft or acres) \| ft²		4.5
Operating Properties \| Single-tenant data centers \| Unconsolidated Real Estate Joint Ventures
Investments in real estate
Number of real estate properties	15
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		1.6
Properties under development \| Office Properties
Investments in real estate
Number of real estate properties	10
Properties under development \| Single-tenant data centers
Investments in real estate
Number of real estate properties	1
Properties under development, partially-operational
Investments in real estate
Number of real estate properties	1
Properties under development, expansions of fully-operational properties
Investments in real estate
Number of real estate properties	1
Land controlled for future development
Investments in real estate
Area of real estate property (in sqft or acres)		11.0		860
Other Land
Investments in real estate
Area of real estate property (in sqft or acres) \| a				43