INVESTMENT IN EQUITY SECURITIES (Details) - USD ($) $ in Thousands, shares in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2016	Dec. 31, 2018
Marketable Securities [Line Items]
Investment in equity securities	$ 40,093		$ 40,093			$ 36,181
Unrealized gain (loss) from change in fair value	(2,294)	$ 1,782	11,731	$ (4,186)
Unrealized gain (loss) from sale	(100)		1,900
Investment income, dividend	$ 500	$ 600	$ 1,700	1,900
Maximum allowable increase, percent			50.00%
Number of shares disposed (in shares)	0.1		0.7
Proceeds received from sale of equity securities	$ 1,300		$ 7,819	$ 0
Maximum
Marketable Securities [Line Items]
Investment shares, transfer restrictions, percent (no more than)			25.00%
RESI
Marketable Securities [Line Items]
Number of investment shares acquired (in shares)					4.1
Number of securities outstanding (in shares)	3.5		3.5			4.1