INVESTMENT IN AN UNCONSOLIDATED ENTITY - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		6 Months Ended
	Jul. 19, 2019	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019	Aug. 21, 2019
Schedule of Equity Method Investments [Line Items]
Investment in an unconsolidated entity		$ 239,474		$ 239,474		$ 253,371
Equity in loss of an unconsolidated entity		835	$ 0	1,996	$ 0
SREIT
Schedule of Equity Method Investments [Line Items]
Equity in loss of an unconsolidated entity		835		4,092
Equity in share loss of an unconsolidated entity				(4,100)
Purchase and Sales Agreement | SREIT
Schedule of Equity Method Investments [Line Items]
Investment in an unconsolidated entity		$ 239,500		239,500
Equity in gain for dilution of an unconsolidated entity				2,100
Investment income, dividends				$ 11,900
REIT Properties III | Purchase and Sales Agreement
Schedule of Equity Method Investments [Line Items]
Units acquired (in units)	307,953,999
Units acquired	$ 271,000
Units acquired (in dollars per unit)	$ 0.88
Ownership percentage	33.30%	27.50%		27.50%			31.30%
Units disposed (in units)							18,392,100
Units disposed							$ 16,200
Units held (in units)		289,561,899		289,561,899
Investment in an unconsolidated entity		$ 225,900		$ 225,900
Units, closing price (in dollars per unit)		$ 0.78		$ 0.78
REIT Properties III | Purchase and Sales Agreement | For Six Months Following the Listing of the Purchaser
Schedule of Equity Method Investments [Line Items]
Percent of units to be hold		100.00%		100.00%
REIT Properties III | Purchase and Sales Agreement | For Twelve Months Following the Listing of the Purchaser
Schedule of Equity Method Investments [Line Items]
Percent of units to be hold		50.00%		50.00%