BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES - Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Accounting Policies [Abstract]
Fixed lease income - operating leases	$ 43,659	$ 41,910	$ 87,499	$ 83,843
Variable lease income - operating leases	2,103	1,302	4,072	3,082
Revenue from contracts with customers	894	698	1,733	1,391
Total revenue	$ 46,656	$ 43,910	$ 93,304	$ 88,316