INCOME TAXES - Schedule of Provision (Benefit) for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current provision for income taxes:
Federal	$ 77,477	$ 113,737	$ 80,420
State	6,625	2,273	5,720
Current income tax expense (benefit)	84,102	116,010	86,140
Deferred (benefit) provision for income taxes:
Federal	(196,468)	8,555	(26,637)
State	37,006	(2,437)	(1,809)
Deferred income tax expense (benefit)	(159,462)	6,118	(28,446)
Provision for income taxes	$ (75,360)	$ 122,128	$ 57,694