COMMITMENTS AND CONTINGENCIES (Details) $ in Thousands		1 Months Ended	12 Months Ended
	Oct. 21, 2020 USD ($)	Feb. 28, 2021 property	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Jul. 23, 2021 USD ($)	Sep. 30, 2004 ft²
Property Subject to or Available for Operating Lease [Line Items]
Real estate ventures aggregate indebtedness			$ 1,204,779	$ 961,509
Limited payment guarantee, percent of principle balance (up to)					25.00%
Commerce Square | Preferred Equity Investment Obligation
Property Subject to or Available for Operating Lease [Line Items]
Other commitments			20,000
Amount committed to date			7,200
Schuylkill Yards Project
Property Subject to or Available for Operating Lease [Line Items]
Other commitments			6,600
Estimated potential additional contribution obligation			2,200
Natural Disasters and Other Casualty Events
Property Subject to or Available for Operating Lease [Line Items]
Number of properties damaged | property		1
Write-off of fixed assets				1,200
Restoration liability			800	7,200
Business interruption costs				3,900
Insurance proceeds			2,800	15,300
Natural Disasters and Other Casualty Events | Other Income
Property Subject to or Available for Operating Lease [Line Items]
Insurance proceeds				3,000
Natural Disasters and Other Casualty Events | Accounts Payable and Accrued Liabilities
Property Subject to or Available for Operating Lease [Line Items]
Restoration liability				$ 1,900
3025 JFK Venture
Property Subject to or Available for Operating Lease [Line Items]
Construction loan amount			186,700		$ 186,700
Unconsolidated Real Estate Ventures
Property Subject to or Available for Operating Lease [Line Items]
Real estate ventures aggregate indebtedness			1,204,800
Two Logan Square
Property Subject to or Available for Operating Lease [Line Items]
Rentable square feet | ft²						708,844
Settlement liabilities			$ 600
Two Logan Square | Secured Debt
Property Subject to or Available for Operating Lease [Line Items]
Repayments of long-term debt	$ 79,800