INCOME TAXES - Income tax benefit (expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current
State	$ (11)	$ (26)	$ 19
Deferred
Federal	(60,408)	(41,567)	190,195
State	(12)	(309)	5,859
Total	(60,420)	(41,876)	196,054
Total income tax benefit (expense), net	$ (60,431)	$ (41,902)	$ 196,073