REAL ESTATE-RELATED SECURITIES (Activity for the Real Estate-Related Securities) (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2020 USD ($)
Amortized Cost Basis
Real estate-related securities as of September 30, 2020	$ 75,151
Unrealized Gain
Real estate-related securities as of September 30, 2020	61
Fair Value
Real estate-related securities as of January 1, 2020	0
Real estate-related securities as of September 30, 2020	75,212
CMBS
Amortized Cost Basis
Real estate-related securities as of January 1, 2020	0
Face value of real estate-related securities acquired	91,440
Premiums and discounts on purchase of real estate-related securities, net of acquisition costs	(14,796)
Amortization of discount (premium) on real estate-related securities	(45)
Principal payments received on real estate-related securities	(1,448)
Real estate-related securities as of September 30, 2020	75,151
Unrealized Gain
Real estate-related securities as of January 1, 2020	0
Unrealized gain on real estate-related securities	61
Real estate-related securities as of September 30, 2020	61
Fair Value
Real estate-related securities as of January 1, 2020	0
Face value of real estate-related securities acquired	91,440
Premiums and discounts on purchase of real estate-related securities, net of acquisition costs	(14,796)
Amortization of discount (premium) on real estate-related securities	(45)
Principal payments received on real estate-related securities	(1,448)
Unrealized gain on real estate-related securities	61
Real estate-related securities as of September 30, 2020	$ 75,212