SEGMENT DISCLOSURE - Reconciliation of Segment Operating Income to Net Income Attributable to Company (Details) - USD ($)	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Interest and other income	$ 2,912,000			$ 4,175,000			$ 7,810,000	$ 12,955,000
Asset management and other fees to related parties	(2,387,000)			(2,699,000)			(7,408,000)	(10,496,000)
Interest expense	(2,643,000)			(2,403,000)			(8,706,000)	(8,998,000)
General and administrative	(1,736,000)			(1,384,000)			(5,138,000)	(4,793,000)
Transaction costs	0			(340,000)			0	(600,000)
Depreciation and amortization	(5,273,000)			(5,180,000)			(15,728,000)	(21,995,000)
Loss on early extinguishment of debt	(281,000)			0			(281,000)	(29,982,000)
Impairment of real estate	0			0	$ 0		0	(69,000,000)
Gain on sale of real estate	0			302,000			0	433,104,000
(LOSS) INCOME BEFORE (BENEFIT) PROVISION FOR INCOME TAXES	(5,348,000)			2,943,000			(11,358,000)	347,732,000
Benefit (provision) for income taxes	18,000			(87,000)			731,000	(686,000)
NET (LOSS) INCOME	(5,330,000)	$ (4,041,000)	$ (1,256,000)	2,856,000	$ 52,567,000	$ 291,623,000	(10,627,000)	347,046,000
Net loss (income) attributable to noncontrolling interests	7,000			(8,000)			1,000	165,000
NET (LOSS) INCOME ATTRIBUTABLE TO THE COMPANY	(5,323,000)			2,848,000			(10,626,000)	347,211,000
Reportable segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total segment net operating income	6,642,000			12,927,000			25,208,000	55,754,000
Expense reimbursements to related parties—corporate	(901,000)			(652,000)			(2,581,000)	(1,840,000)
Corporate and Reconciling Items
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Interest and other income	62,000			1,408,000			98,000	3,226,000
Asset management and other fees to related parties	(2,387,000)			(2,699,000)			(7,408,000)	(10,496,000)
Interest expense	(2,473,000)			(2,038,000)			(8,056,000)	(7,515,000)
General and administrative	(999,000)			(807,000)			(3,125,000)	(2,945,000)
Non-segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Expense reimbursements to related parties—corporate	$ (639,000)			$ (630,000)			$ (2,066,000)	$ (1,819,000)