BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES - Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Fixed lease income	$ 44,342	$ 43,193	$ 88,084	$ 83,314
Variable lease income	1,548	0	2,632	0
Revenues	46,934	46,197	92,542	89,232
Non-Lease Components
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	1,335	0	2,546
Other Property Revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 1,044	$ 1,669	$ 1,826	$ 3,372