SEGMENT INFORMATION - Unconsolidated Real Estate Ventures of Company's Reportable Segments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Investment in real estate ventures, at equity	$ 570,455	$ 552,494
Equity in income (loss) of real estate venture	(191,585)	(77,915)	$ (22,016)
Philadelphia CBD
Segment Reporting Information [Line Items]
Investment in real estate ventures, at equity	452,334	450,136
Equity in income (loss) of real estate venture	(155,567)	(25,793)	(11,764)
Mid-Atlantic Office JV
Segment Reporting Information [Line Items]
Investment in real estate ventures, at equity	10,844	0
Equity in income (loss) of real estate venture	7,141	(26,448)	412
MAP Venture
Segment Reporting Information [Line Items]
Investment in real estate ventures, at equity	0	(48,733)
Equity in income (loss) of real estate venture	(6,542)	(10,581)	(8,340)
Austin, Texas
Segment Reporting Information [Line Items]
Investment in real estate ventures, at equity	90,495	79,160
Equity in income (loss) of real estate venture	(4,001)	0	0
Other
Segment Reporting Information [Line Items]
Investment in real estate ventures, at equity	16,782	71,931
Equity in income (loss) of real estate venture	$ (32,616)	$ (15,093)	$ (2,324)