INVESTMENT IN UNCONSOLIDATED REAL ESTATE VENTURES - Narrative (Details)				3 Months Ended		9 Months Ended
	Jul. 29, 2022 USD ($) numberOfLoan	Jun. 30, 2022	Mar. 17, 2022 USD ($) ft²	Sep. 30, 2022 USD ($) a ft² property apartment	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($) a ft² property apartment	Sep. 30, 2021 USD ($)	Jul. 14, 2022 USD ($) ft²	Dec. 31, 2021 USD ($)	Dec. 01, 2021 USD ($) ft² apartment property
Schedule of Equity Method Investments [Line Items]
Number of real estate properties | property				78		78
Investment in unconsolidated real estate ventures				$ 579,457,000		$ 579,457,000			$ 435,506,000
Accounts receivable				11,398,000		11,398,000			11,875,000
Investment in real estate ventures				$ 546,935,000		$ 546,935,000			411,110,000
Rentable area (in square feet) | ft²				13,664,209		13,664,209
Principal balance outstanding				$ 2,074,610,000		$ 2,074,610,000
Purchase price						3,446,000	$ 0
Unsecured Debt
Schedule of Equity Method Investments [Line Items]
Principal balance outstanding				2,074,610,000		2,074,610,000			1,851,610,000
Unsecured Debt | $600 million Unsecured Credit Facility
Schedule of Equity Method Investments [Line Items]
Principal balance outstanding				246,000,000		246,000,000			23,000,000
Debt instrument, face amount				600,000,000		$ 600,000,000
Unsecured Debt | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate | $600 million Unsecured Credit Facility
Schedule of Equity Method Investments [Line Items]
Spread on variable rate						1.15%
Unsecured Debt | Daily SOFR Adjustment | $600 million Unsecured Credit Facility
Schedule of Equity Method Investments [Line Items]
Spread on variable rate		0.10%				0.10%
Real Estate Venture
Schedule of Equity Method Investments [Line Items]
Accounts receivable				2,900,000		$ 2,900,000			$ 2,500,000
Management Fees | Real Estate Venture
Schedule of Equity Method Investments [Line Items]
Service and other revenue				2,200,000	$ 2,100,000	6,200,000	6,200,000
Leasing Commission Income | Real Estate Venture
Schedule of Equity Method Investments [Line Items]
Service and other revenue				700,000	$ 700,000	1,700,000	$ 2,600,000
3151 Market Street
Schedule of Equity Method Investments [Line Items]
Investment in real estate ventures								$ 308,000,000
Rentable area (in square feet) | ft²								417,000
3151 Market Street | Joint Venture With Unaffiliated Third Party
Schedule of Equity Method Investments [Line Items]
Investment in real estate ventures								$ 55,000,000
Unconsolidated Real Estate Ventures
Schedule of Equity Method Investments [Line Items]
Investment in unconsolidated real estate ventures				$ 546,900,000		$ 546,900,000
Unconsolidated Real Estate Ventures | Minimum
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage				15.00%		15.00%
Unconsolidated Real Estate Ventures | Maximum
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage				70.00%		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		5
Rentable area (in square feet) | ft²				9,100,000		9,100,000
Unconsolidated Real Estate Ventures | Other Liabilities
Schedule of Equity Method Investments [Line Items]
Investment in unconsolidated real estate ventures				$ 32,500,000		$ 32,500,000
Unconsolidated Real Estate Ventures | Unconsolidated Properties
Schedule of Equity Method Investments [Line Items]
Number of real estate properties | property				13		13
Number of properties with negative investment balances | property				1		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		2
Area of land (in acres) | a				1.4		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				4		4
Area of land (in acres) | a				7.5		7.5
Unconsolidated Real Estate Ventures | Mixed Use Tower
Schedule of Equity Method Investments [Line Items]
Number of unconsolidated investments in Real Estate Ventures | property				1		1
Rentable area (in square feet) | ft²				200,000		200,000
Number of apartment units (in units) | apartment				250		250
Unconsolidated Real Estate Ventures | Residential Tower
Schedule of Equity Method Investments [Line Items]
Number of unconsolidated investments in Real Estate Ventures | property				1		1
Number of apartment units (in units) | apartment				321		321
One Uptown Venture
Schedule of Equity Method Investments [Line Items]
Investment in real estate ventures										$ 328,400,000
Number of apartment residence | apartment										341
Joint venture, funding committed by other party										$ 64,500,000
One Uptown Venture | Carry Guarantee | Loans Payable
Schedule of Equity Method Investments [Line Items]
Guarantee percent	30.00%
One Uptown Venture | Limited Payment Guarantee | Loans Payable
Schedule of Equity Method Investments [Line Items]
Guarantee percent	15.00%
One Uptown Venture | Preferred Stock
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage										50.00%
One Uptown Venture | Common Stock
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage										50.00%
One Uptown Venture | Canyon Partners Real Estate
Schedule of Equity Method Investments [Line Items]
Number of joint ventures | property										2
One Uptown Venture | Construction Loans
Schedule of Equity Method Investments [Line Items]
Number of loans closed | numberOfLoan	2
Principal balance outstanding	$ 121,700,000
One Uptown Venture | Construction Loans | Multifamily Joint Venture
Schedule of Equity Method Investments [Line Items]
Principal balance outstanding	$ 85,000,000
One Uptown Venture | Construction Loans | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Schedule of Equity Method Investments [Line Items]
Spread on variable rate	3.00%
One Uptown Venture | Construction Loans | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate | Multifamily Joint Venture
Schedule of Equity Method Investments [Line Items]
Spread on variable rate	2.45%
One Uptown Venture | Class A Workspace
Schedule of Equity Method Investments [Line Items]
Rentable area (in square feet) | ft²										348,000
One Uptown Venture | Street Level Retail
Schedule of Equity Method Investments [Line Items]
Rentable area (in square feet) | ft²										15,000
Joint Venture With Unaffiliated Third Party | 3151 Market Street | Joint Venture With Unaffiliated Third Party
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage								45.00%
Cira Square REIT, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage			20.00%
Gross purchase price			$ 383,000,000
Purchase price			$ 28,600,000
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 | Secured Debt
Schedule of Equity Method Investments [Line Items]
Debt instrument, face amount			$ 257,700,000
Cira Square REIT, LLC | Office properties
Schedule of Equity Method Investments [Line Items]
Rentable area (in square feet) | ft²			862,692