SEGMENT INFORMATION - Schedule of Net Operating Income of Company's Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Segment Reporting Information [Line Items]
Total revenue	$ 120,571	$ 125,346	$ 242,087	$ 251,830
Operating expenses	(45,356)	(46,314)	(92,947)	(93,728)
Net operating income	75,215	79,032	149,140	158,102
Operating Segments | Philadelphia CBD
Segment Reporting Information [Line Items]
Total revenue	56,683	56,723	112,071	112,711
Operating expenses	(20,372)	(19,071)	(41,003)	(38,953)
Net operating income	36,311	37,652	71,068	73,758
Operating Segments | Pennsylvania Suburbs
Segment Reporting Information [Line Items]
Total revenue	31,310	31,666	63,241	63,685
Operating expenses	(9,963)	(9,897)	(20,018)	(19,256)
Net operating income	21,347	21,769	43,223	44,429
Operating Segments | Austin, Texas
Segment Reporting Information [Line Items]
Total revenue	18,499	22,154	36,650	45,409
Operating expenses	(7,785)	(8,834)	(15,552)	(17,847)
Net operating income	10,714	13,320	21,098	27,562
Operating Segments | Other
Segment Reporting Information [Line Items]
Total revenue	9,995	10,308	20,518	21,276
Operating expenses	(4,380)	(5,132)	(9,604)	(10,594)
Net operating income	5,615	5,176	10,914	10,682
Corporate
Segment Reporting Information [Line Items]
Total revenue	4,084	4,495	9,607	8,749
Operating expenses	(2,856)	(3,380)	(6,770)	(7,078)
Net operating income	$ 1,228	$ 1,115	$ 2,837	$ 1,671