REAL ESTATE DISPOSITIONS (Revenue and Expenses for Real Estate Held-for-Sale) (Details) - Disposed of by Sale - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues
Rental income	$ 11,458	$ 30,744	$ 94,073
Other operating income	911	1,171	5,668
Total revenues	12,369	31,915	99,741
Expenses
Operating, maintenance, and management	3,423	9,117	28,931
Real estate taxes and insurance	2,217	4,035	12,188
Asset management fees to affiliate	784	2,435	6,458
Depreciation and amortization	3,784	13,066	39,038
Interest expense	2,459	8,083	17,974
Total expenses	$ 12,667	$ 36,736	$ 104,589