SEGMENT INFORMATION - Schedule of Real Estate Investments, at Cost of Company's Reportable Segments (Details) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Segment Reporting Information [Line Items]
Operating properties	$ 3,260,497	$ 3,374,780
Right of use asset - operating leases, net	18,108	18,412
Construction-in-progress	90,950	94,628
Land held for development	74,541	81,318
Prepaid leasehold interests in land held for development, net	27,762	27,762
Continuing Operations
Segment Reporting Information [Line Items]
Operating properties	3,319,298	3,374,780
Discontinued Operations
Segment Reporting Information [Line Items]
Operating properties	58,801	0
Total Core Segments | Continuing Operations
Segment Reporting Information [Line Items]
Operating properties	2,978,137	3,097,025
Philadelphia CBD | Continuing Operations
Segment Reporting Information [Line Items]
Operating properties	1,580,520	1,556,696
Pennsylvania Suburbs | Continuing Operations
Segment Reporting Information [Line Items]
Operating properties	882,593	869,179
Austin, Texas | Continuing Operations
Segment Reporting Information [Line Items]
Operating properties	515,024	671,150
Other | Continuing Operations
Segment Reporting Information [Line Items]
Operating properties	$ 282,360	$ 277,755