REAL ESTATE DEBT SECURITIES (Schedule of Investments in Debt Securities) (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended			121 Months Ended
	Mar. 20, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2019
Schedule of Available-for-sale Securities [Line Items]
Outstanding Principal Balance		$ 0	$ 13,000		$ 0
Redemptions of common stock	$ 8,600	10,028	123,613	$ 74,780	285,400
Battery Point
Schedule of Available-for-sale Securities [Line Items]
Redemptions of common stock (in shares)	13,000
Stock redeemed (in dollars per share)	$ 1,000
Redemptions of common stock	$ 8,600
Stock redeemed, accrued interest and exit fees	$ 900
Number of securities received (in shares)	210,000
Price per share (in dollars per share)	$ 25
Battery Point | Series B Preferred Units
Schedule of Available-for-sale Securities [Line Items]
Outstanding Principal Balance		0			0
Book Value		$ 0	$ 10,859		$ 0