INVESTMENT IN UNCONSOLIDATED REAL ESTATE VENTURES - Mid-Atlantic Office JV (Details) $ in Thousands		12 Months Ended
	Dec. 21, 2020 USD ($) ft² property	Dec. 31, 2022 USD ($) property	Dec. 31, 2021 USD ($)
Schedule of Equity Method Investments [Line Items]
Number of real estate properties | property		77
Investment in real estate ventures, at equity		$ 532,224	$ 411,110
Mid-Atlantic Office JV Loan
Schedule of Equity Method Investments [Line Items]
Secured construction loan with total borrowing capacity		18,500
Philadelphia CBD
Schedule of Equity Method Investments [Line Items]
Investment in real estate ventures, at equity		387,301	317,959
Metropolitan Washington, D.C.
Schedule of Equity Method Investments [Line Items]
Investment in real estate ventures, at equity		$ 83,903	$ 85,867
Mid-Atlantic Office Venture
Schedule of Equity Method Investments [Line Items]
Ownership percentage	40.00%	40.00%
Ownership percentage of total common equity	20.00%
Joint venture, funding from debt	$ 147,400
Proceeds from issuance of secured debt	$ 120,800
Mid-Atlantic Office Venture | Mid-Atlantic Office JV Loan | Maximum
Schedule of Equity Method Investments [Line Items]
Debt instrument, interest rate, stated percentage		5.70%
Mid-Atlantic Office Venture | Mid-Atlantic Office JV Loan | LIBOR
Schedule of Equity Method Investments [Line Items]
Basis spread on interest rate (as percent)		3.15%
Mid-Atlantic Office Venture | Preferred Equity Securities
Schedule of Equity Method Investments [Line Items]
Ownership percentage	25.00%
Investment in real estate ventures, at equity	$ 20,000
Mid-Atlantic Office Venture | Common Equity Securities
Schedule of Equity Method Investments [Line Items]
Ownership percentage	15.00%
Office Properties | Mid-Atlantic Office Venture
Schedule of Equity Method Investments [Line Items]
Number of real estate properties | property	12
Rentable square feet | ft²	1,128,645
Aggregate sales price	$ 192,900
Office Properties | Mid-Atlantic Office Venture | Philadelphia CBD
Schedule of Equity Method Investments [Line Items]
Number of real estate properties | property	9
Office Properties | Mid-Atlantic Office Venture | Metropolitan Washington, D.C.
Schedule of Equity Method Investments [Line Items]
Number of real estate properties | property	3