SEGMENT REPORTING - Segment Assets and Accumulated Depreciation (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021
Segment Reporting Information [Line Items]
Property owned	$ 2,390,952	$ 2,271,170
Less accumulated depreciation	(465,752)	(443,592)
Total property owned	1,925,200	1,827,578
Mortgage loans receivable	0	43,276
Cash and cash equivalents	13,313	31,267	$ 10,816
Restricted cash	2,409	7,358	$ 1,610
Other assets	24,651	30,582
Total Assets	1,965,573	1,940,061
Multifamily
Segment Reporting Information [Line Items]
Property owned	2,364,167	2,244,250
Less accumulated depreciation	(457,985)	(436,004)
Total property owned	1,906,182	1,808,246
All Other
Segment Reporting Information [Line Items]
Property owned	26,785	26,920
Less accumulated depreciation	(7,767)	(7,588)
Total property owned	$ 19,018	$ 19,332