SEGMENT DISCLOSURE - Reconciliation of Segment Operating Income to Net Income Attributable to Company (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Interest and other income									$ 10,503	$ 16,025	$ 14,703
Asset management and other fees to related parties									(9,793)	(13,121)	(18,959)
Interest expense									(11,415)	(12,175)	(26,894)
General and administrative									(6,772)	(6,354)	(9,167)
Transaction costs									0	(574)	(938)
Depreciation and amortization									(21,406)	(27,374)	(53,228)
Loss on early extinguishment of debt									(281)	(29,982)	(808)
Impairment of real estate									0	(69,000)	0
Gain on sale of real estate									0	433,104	0
(LOSS) INCOME BEFORE (BENEFIT) PROVISION FOR INCOME TAXES									(15,737)	346,403	2,067
Benefit (provision) for income taxes									722	(882)	(925)
NET (LOSS) INCOME	$ (4,388)	$ (5,330)	$ (4,041)	$ (1,256)	$ (1,525)	$ 2,856	$ 52,567	$ 291,623	(15,015)	345,521	1,142
Net (income) loss attributable to noncontrolling interests									(1)	152	(21)
NET (LOSS) INCOME ATTRIBUTABLE TO THE COMPANY	$ (4,390)	$ (5,323)	$ (4,043)	$ (1,260)	$ (1,538)	$ 2,848	$ 52,566	$ 291,797	(15,016)	345,673	1,121
Operating Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total segment net operating income									32,641	67,251	109,457
Expense reimbursements to related parties—corporate									(3,491)	(2,382)	(2,445)
Corporate And Reconciling Items
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Interest and other income									104	3,329	0
Asset management and other fees to related parties									(9,793)	(13,121)	(18,959)
Interest expense									(10,547)	(10,361)	(25,482)
General and administrative									(4,212)	(4,069)	(4,928)
Corporate, Non-Segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Expense reimbursements to related parties—corporate									$ (2,243)	$ (2,800)	$ (3,047)