Acquisitions, Dispositions and Assets Held for Sale - Narrative (Details)		1 Months Ended					12 Months Ended
	Feb. 11, 2022 ft² USD ($)	Nov. 30, 2021 USD ($) property	Apr. 30, 2021 USD ($) ft² item	Dec. 31, 2020 USD ($) ft² a property	Jan. 31, 2020 USD ($)	Dec. 31, 2019 USD ($) ft² item	Dec. 31, 2021 USD ($) property	Dec. 31, 2020 USD ($) ft² a property	Dec. 31, 2019 USD ($) ft² property item
Schedule of Equity Method Investments [Line Items]
Acquisition of real estate							$ 208,342,000	$ 45,688,000	$ 165,208,000
Number of Real Estate Properties | property							64
Income (loss) from unconsolidated real estate ventures, net							$ (2,070,000)	(20,336,000)	(1,395,000)
Proceeds from sale of real estate							14,370,000	154,493,000	377,511,000
Gain on sale of real estate							$ 11,290,000	59,477,000	$ 104,991,000
The Batley
Schedule of Equity Method Investments [Line Items]
Number Of Units Acquired | property		432
Purchase consideration		$ 205,300,000
Transaction costs		$ 3,100,000
Former Americana Hotel Site
Schedule of Equity Method Investments [Line Items]
Acquisition of real estate				$ 47,300,000
Future Development Parcel and Other Assets
Schedule of Equity Method Investments [Line Items]
Purchase consideration				65,000,000.0
Transaction costs				688,000
Deferred payment until approval of certain entitlements				$ 20,000,000.0				$ 20,000,000.0
Area of Real Estate Property | a				1.4				1.4
Acquisition of Other Parcels
Schedule of Equity Method Investments [Line Items]
Acquisition of real estate				$ 17,700,000
Number of Real Estate Properties | property				3				3
Washington, D.C. | Multifamily Segment | F1RST Residences
Schedule of Equity Method Investments [Line Items]
Acquisition of real estate						$ 160,500,000
Transaction costs						$ 4,700,000
Number of Units in Real Estate Property | item						325			325
Washington, D.C. | Retail Site | F1RST Residences
Schedule of Equity Method Investments [Line Items]
Area of Real Estate Property | ft²						21,000			21,000
Maximum | Former Americana Hotel Site
Schedule of Equity Method Investments [Line Items]
Area of Real Estate Property | ft²				550,000				550,000
Disposal Group, Disposed of by Sale | Metropolitan Park
Schedule of Equity Method Investments [Line Items]
Proceeds from sale of real estate					$ 155,000,000.0
Gain on sale of real estate					$ 59,500,000
Disposal Group, Disposed of by Sale | Commercial Assets
Schedule of Equity Method Investments [Line Items]
Number of real estate properties sold | property									3
Proceeds from sale of real estate									$ 165,400,000
Disposal Group, Disposed of by Sale | Commercial Assets And Real Estate Venture
Schedule of Equity Method Investments [Line Items]
Gain on sale of real estate									105,000,000.0
Fortress Investment Group Real Estate Venture | Subsequent Event
Schedule of Equity Method Investments [Line Items]
Area of Real Estate Property | ft²	1,600,000
Fortress Investment Group Real Estate Venture | Commercial Assets | Subsequent Event
Schedule of Equity Method Investments [Line Items]
Number of real estate units to be acquired	4
Potomac Yard Mixed Use Development | J.P. Morgan Global Alternatives ("J.P. Morgan")
Schedule of Equity Method Investments [Line Items]
Gain from contribution to real estate ventures			$ 11,300,000
Area of Real Estate Property | ft²			2,000,000.0
Number of real estate ventures | item			2
Central Place Tower | Unconsolidated Real Estate Ventures
Schedule of Equity Method Investments [Line Items]
Proceeds from sale of real estate						$ 220,000,000.0			220,000,000.0
Gain on sale of real estate									$ 53,400,000
Area of Real Estate Property | ft²						552,000			552,000
Equity method investment ownership percentage sold						50.00%			50.00%