DISCONTINUED OPERATIONS - Effect on Net Income from Properties Classified as Discontinued Operations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
REVENUE	$ 47,436	$ 45,406	$ 139,978	$ 134,638
EXPENSES
Property operating expenses, excluding real estate taxes	14,485	14,438	43,231	42,618
Real estate taxes	5,425	5,049	16,231	15,073
Depreciation and amortization	18,751	19,164	55,299	58,812
General and administrative expenses	3,448	3,147	10,803	11,114
TOTAL EXPENSES	43,840	43,292	131,027	149,791
Interest expense	(7,694)	(8,193)	(23,180)	(25,051)
Gain (loss) on sale of discontinued operations			39,774	25,799
INCOME (LOSS) FROM DISCONTINUED OPERATIONS	0	570	0	14,690
Discontinued Operations, Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
REVENUE	0	0	0	353
EXPENSES
Property operating expenses, excluding real estate taxes	0	0	0	25
Real estate taxes	0	0	0	35
Depreciation and amortization	0	0	0	2
General and administrative expenses	0	0	0	14
TOTAL EXPENSES	0	0	0	76
Operating income (loss)	0	0	0	277
Interest expense	0	0	0	(1)
Other income	0	0	0	14
Income (loss) from discontinued operations before gain (loss) on sale of discontinued operations	0	0	0	290
Gain (loss) on sale of discontinued operations	0	570	0	14,400
INCOME (LOSS) FROM DISCONTINUED OPERATIONS	$ 0	$ 570	$ 0	$ 14,690