BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES - Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Disaggregation of Revenue [Line Items]
Fixed lease income - operating leases	$ 43,840	$ 41,934
Variable lease income - operating leases	1,969	1,780
Revenues	46,648	44,406
Other Property Revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 839	$ 692