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Investment in Unconsolidated Real Estate Ventures - Textual (Details) $ in Thousands		3 Months Ended
	Feb. 02, 2021 USD ($)	Mar. 31, 2021 USD ($) a ft² property investment apartment	Mar. 31, 2020 USD ($)	Feb. 02, 2021 ft²	Feb. 02, 2021 a	Feb. 02, 2021	Dec. 31, 2020 USD ($)
Schedule of Equity Method Investments [Line Items]
Number of properties \| property		81
Investment in Real Estate Ventures		$ 433,046					$ 401,327
Accounts receivable		14,665					13,536
Investment in joint venture		415,823					389,811
3025 JFK Venture
Schedule of Equity Method Investments [Line Items]
Area of land (in acres)				1	1
Equity method investment, ownership percentage						55.00%
Lease agreement term	99 years
Investment in joint venture	$ 34,800	34,800
Area of building to be constructed \| ft²				570,000
Estimated project cost	287,000
Ownership interest held by partner						45.00%
Joint venture, funding committed by other party	$ 45,000
Joint venture, funding committed		20,200
Construction loan amount		$ 187,000
Minimum
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage		15.00%
Maximum
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage		70.00%
Real Estate Venture
Schedule of Equity Method Investments [Line Items]
Accounts receivable		$ 2,100					$ 1,200
Real Estate Venture \| Management Fees
Schedule of Equity Method Investments [Line Items]
Service and other revenue		2,000	$ 1,100
Real Estate Venture \| Leasing Commission Income
Schedule of Equity Method Investments [Line Items]
Service and other revenue		1,300	$ 400
Unconsolidated Real Estate Ventures
Schedule of Equity Method Investments [Line Items]
Investment in Real Estate Ventures		$ 415,800
Unconsolidated Real Estate Ventures \| Office properties
Schedule of Equity Method Investments [Line Items]
Number of unconsolidated investments in Real Estate Ventures \| investment		5
Rentable area (in square feet) \| ft²		8,400,000
Unconsolidated Real Estate Ventures \| Unconsolidated Properties
Schedule of Equity Method Investments [Line Items]
Number of properties \| property		10
Number of properties with negative investment balances \| property		1
Unconsolidated Real Estate Ventures \| Land Held For Development
Schedule of Equity Method Investments [Line Items]
Number of unconsolidated investments in Real Estate Ventures \| investment		2
Area of land (in acres) \| a		1.4
Unconsolidated Real Estate Ventures \| Land Under Active Development
Schedule of Equity Method Investments [Line Items]
Number of unconsolidated investments in Real Estate Ventures \| investment		1
Area of land (in acres) \| a		1.0
Unconsolidated Real Estate Ventures \| Mixed Use Tower
Schedule of Equity Method Investments [Line Items]
Number of unconsolidated investments in Real Estate Ventures \| investment		1
Rentable area (in square feet) \| ft²		200,000
Number of apartment units (in units) \| apartment		250
Unconsolidated Real Estate Ventures \| Residential Tower
Schedule of Equity Method Investments [Line Items]
Number of unconsolidated investments in Real Estate Ventures \| investment		1
Number of apartment units (in units) \| apartment		321
Other Liabilities \| Unconsolidated Real Estate Ventures
Schedule of Equity Method Investments [Line Items]
Investment in Real Estate Ventures		$ (17,200)