REAL ESTATE DEBT SECURITIES (Interest Income) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Contractual interest income	$ 2,120,000	$ 1,884,000	$ 1,105,000
Other-than-temporary impairment of debt securities	0	$ 2,500,000	0
Probable percent of contractual cash flows to be collected		100.00%
Discount rate		12.00%
Debt Securities
Schedule of Available-for-sale Securities [Line Items]
Contractual interest income	356,000	$ 1,910,000	1,217,000
Interest accretion	4,000	59,000	315,000
Accretion of commitment fee, net of closing costs and acquisition fee	9,000	49,000	250,000
Interest income from real estate debt securities	369,000	$ 2,018,000	$ 1,782,000
Other-than-temporary impairment of debt securities	$ 9,000