SEGMENT DISCLOSURE - Reconciliation Of Segment Operating Income (Details) - USD ($)	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Segment disclosure
Interest and other income	$ 4,888,000		$ 3,559,000		$ 8,780,000	$ 7,020,000
Asset management and other fees to related parties	(4,288,000)		(6,143,000)		(10,174,000)	(12,354,000)
Interest expense	(2,550,000)		(6,811,000)		(6,595,000)	(13,444,000)
General and administrative	(1,621,000)		(1,915,000)		(3,409,000)	(5,291,000)
Transaction costs	(216,000)		(344,000)		(260,000)	(344,000)
Depreciation and amortization	(7,185,000)		(13,325,000)		(16,815,000)	(26,473,000)
Loss on early extinguishment of debt	(4,911,000)		0		(29,982,000)	0
Impairment of real estate	(2,800,000)	$ (66,200,000)	0		(69,000,000)	0
Gain on sale of real estate	55,221,000		0		432,802,000	0
Income before provision for income taxes	52,848,000		2,241,000		344,789,000	3,251,000
Provision for income taxes	(281,000)		(292,000)		(599,000)	(680,000)
NET INCOME	52,567,000	$ 291,623,000	1,949,000	$ 622,000	344,190,000	2,571,000
Net (income) loss attributable to noncontrolling interests	(1,000)		(12,000)		173,000	(16,000)
NET INCOME ATTRIBUTABLE TO THE COMPANY	52,566,000		1,937,000		344,363,000	2,555,000
Reportable segments
Segment disclosure
Income before provision for income taxes	18,012,000		29,352,000		42,827,000	57,577,000
Corporate and Reconciling Items
Segment disclosure
Interest and other income	1,499,000		0		1,818,000	0
Asset management and other fees to related parties	(3,737,000)		(5,504,000)		(8,986,000)	(11,114,000)
Interest expense	(2,014,000)		(6,511,000)		(5,477,000)	(12,960,000)
General and administrative	$ (1,021,000)		$ (1,427,000)		$ (2,138,000)	$ (3,435,000)