SEGMENT DISCLOSURE - Results of Operations (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment disclosure
Interest and other income									$ 16,025	$ 14,703	$ 24,949
Asset management and other fees to related parties									(18,303)	(24,451)	(30,251)
Interest expense									(12,175)	(26,894)	(34,484)
General and administrative									(6,354)	(9,167)	(5,479)
Transaction costs									(574)	(938)	(11,862)
Depreciation and amortization									(27,374)	(53,228)	(58,364)
Loss on early extinguishment of debt	$ 0	$ 0	$ (4,911)	$ (25,071)	$ (808)	$ 0	$ 0	$ 0	(29,982)	(808)	(8,215)
Impairment of real estate	0	0	(2,800)	(66,200)					(69,000)	0	(13,100)
Gain on sale of real estate	0	302	55,221	377,581					433,104	0	408,098
Provision for income taxes									(882)	(925)	(1,376)
NET INCOME	(1,525)	2,856	52,567	291,623	(900)	(529)	1,949	622	345,521	1,142	379,758
Net loss (income) attributable to noncontrolling interests									152	(21)	(21)
NET INCOME ATTRIBUTABLE TO THE COMPANY	$ (1,538)	$ 2,848	$ 52,566	$ 291,797	$ (906)	$ (528)	$ 1,937	$ 618	345,673	1,121	379,737
Reportable segments
Segment disclosure
INCOME FROM CONTINUING OPERATIONS BEFORE PROVISION FOR INCOME TAXES									67,251	109,457	128,452
Reconciliation
Segment disclosure
Interest and other income									3,329	0	0
Asset management and other fees to related parties									(15,921)	(22,006)	(26,787)
Interest expense									(10,361)	(25,482)	(34,070)
General and administrative									(4,069)	(4,928)	(3,018)
Transaction costs									(574)	(938)	(11,862)
Depreciation and amortization									(27,374)	(53,228)	(58,364)
Loss on early extinguishment of debt									(29,982)	(808)	(8,215)
Impairment of real estate									(69,000)	0	(13,100)
Gain on sale of real estate									433,104	0	408,098
INCOME FROM CONTINUING OPERATIONS BEFORE PROVISION FOR INCOME TAXES									$ 346,403	$ 2,067	$ 381,134