INCOME TAXES - Components of the Provision for Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Tax Expense (Benefit)
Current tax benefit	$ (717)	$ 0	$ (717)	$ (6)
Deferred tax expense	42,783	58,617	99,732	136,929
Total income tax expense (benefits)	$ 42,066	$ 58,617	$ 99,015	$ 136,923
Combined federal and state effective income tax rate	23.00%	37.60%	23.20%	37.50%