INVESTMENT IN EQUITY SECURITIES (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2016	Dec. 31, 2020
Marketable Securities [Line Items]
Unrealized gain (loss) on investment in equity securities	$ 0	$ 138	$ 0	$ (12,433)
RESI
Marketable Securities [Line Items]
Number of investment shares acquired (in shares)					4,100,000
Number of securities RESI common stock outstanding (in shares)	0		0			0
Unrealized gain (loss) on investment in equity securities	$ 0	100	$ 0	(12,400)
Investment income, dividend	$ 0	$ 0	$ 0	$ 500