BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Revenue Recognition (Details) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Disaggregation of Revenue [Line Items]
Lease incentives		$ 4,000,000.0	$ 4,000,000.0
Lease incentives, accumulated amortization	$ 2,500,000		2,400,000
Fixed lease payments	12,444,000	13,345,000
Variable lease payments	905,000	1,474,000
Rental and other property income	13,349,000	14,819,000
Hotel income	1,732,000	7,759,000
Rental and other property income	13,349,000	14,819,000
Interest and other income	3,798,000	2,957,000
REVENUES	18,879,000	25,535,000
Tenant recoveries outside of lease agreements	0	0
Remaining performance obligations	0
Allowance for uncollectible accounts receivable	2,600,000		$ 1,900,000
Hotel
Disaggregation of Revenue [Line Items]
Hotel income	1,732,000	7,759,000
Rental and other property income	131,000	462,000
Interest and other income	15,000	32,000
REVENUES	$ 1,878,000	$ 8,253,000