REAL ESTATE OWNED (UNITED DOMINION REALTY, L.P.) - Summary (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Real estate owned
Land	$ 2,162,778	$ 2,164,032
Depreciable property - held and used:
Land improvements	228,452	224,964
Building, improvements, and furniture, fixtures and equipment	10,212,051	10,102,758
Real estate owned	12,775,639	12,602,101
Accumulated depreciation	(4,372,524)	(4,131,353)
Total real estate owned, net of accumulated depreciation	8,403,115	8,470,748
United Dominion Realty L.P.
Real estate owned
Land	711,256	711,256
Depreciable property - held and used:
Land improvements	99,297	96,864
Building, improvements, and furniture, fixtures and equipment	3,088,157	3,067,040
Real estate owned	3,898,710	3,875,160
Accumulated depreciation	(1,867,071)	(1,796,568)
Total real estate owned, net of accumulated depreciation	$ 2,031,639	$ 2,078,592