SEGMENT REPORTING - Segment Assets and Accumulated Depreciation (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Property owned	$ 2,271,170	$ 1,812,557
Less accumulated depreciation	(443,592)	(399,249)
Total property owned	1,827,578	1,413,308
Cash and cash equivalents	31,267	392	$ 26,579
Restricted cash	7,358	6,918	$ 19,538
Other assets	30,582	18,904
Mortgage loans receivable	43,276	24,661
TOTAL ASSETS	1,940,061	1,464,183
Multifamily
Segment Reporting Information [Line Items]
Property owned	2,244,250	1,727,287
Less accumulated depreciation	(436,004)	(368,717)
Total property owned	1,808,246	1,358,570
All Other
Segment Reporting Information [Line Items]
Property owned	26,920	85,270
Less accumulated depreciation	(7,588)	(30,532)
Total property owned	$ 19,332	$ 54,738