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Area of land held.

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INVESTMENT IN UNCONSOLIDATED REAL ESTATE VENTURES - Narrative (Details) $ in Thousands		3 Months Ended
	Mar. 17, 2022 USD ($) ft²	Mar. 31, 2022 USD ($) ft² a property apartment	Mar. 31, 2021 USD ($)	Dec. 31, 2021 USD ($)
Schedule of Equity Method Investments [Line Items]
Number of real estate properties \| property		81
Investment in unconsolidated real estate ventures		$ 461,389		$ 435,506
Accounts receivable		$ 14,214		11,875
Rentable area (in square feet) \| ft²		13,678,136
Purchase Price		$ 3,446	$ 0
Real Estate Venture
Schedule of Equity Method Investments [Line Items]
Accounts receivable		2,600		$ 2,500
Management Fees \| Real Estate Venture
Schedule of Equity Method Investments [Line Items]
Service and other revenue		1,900	2,000
Leasing Commission Income \| Real Estate Venture
Schedule of Equity Method Investments [Line Items]
Service and other revenue		400	$ 1,300
Unconsolidated Real Estate Ventures
Schedule of Equity Method Investments [Line Items]
Investment in unconsolidated real estate ventures		$ 434,600
Unconsolidated Real Estate Ventures \| Minimum
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage		15.00%
Unconsolidated Real Estate Ventures \| Maximum
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage		70.00%
Unconsolidated Real Estate Ventures \| Office properties
Schedule of Equity Method Investments [Line Items]
Number of unconsolidated investments in Real Estate Ventures \| property		5
Rentable area (in square feet) \| ft²		9,100,000
Unconsolidated Real Estate Ventures \| Other Liabilities
Schedule of Equity Method Investments [Line Items]
Investment in unconsolidated real estate ventures		$ 26,800
Unconsolidated Real Estate Ventures \| Unconsolidated Properties
Schedule of Equity Method Investments [Line Items]
Number of real estate 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 \| property		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 \| property		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 \| property		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 \| property		1
Number of apartment units (in units) \| apartment		321
Cira Square REIT, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage	20.00%
Gross purchase price	$ 383,000
Purchase Price	28,600
Cira Square REIT, LLC \| Secured Debt
Schedule of Equity Method Investments [Line Items]
Debt instrument, face amount	$ 257,700
Cira Square REIT, LLC \| Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Schedule of Equity Method Investments [Line Items]
Spread on variable rate	3.50%
Cira Square REIT, LLC \| Office properties
Schedule of Equity Method Investments [Line Items]
Rentable area (in square feet) \| ft²	862,692