INCOME TAXES - Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
The impacts of the differences between the expected U.S. federal statutory income tax to our income tax expense
Expected tax at federal statutory rate	$ 46,997	$ 20,871	$ (6,372)
State income tax, net of federal benefit	4	0	0
Non-deductible executive compensation	987	925	306
Other	(1,506)	(122)	170
Impact of tax reform rate change	124,017	0	0
Change in valuation allowance	(170,495)	(21,579)	5,896
Income tax expense	$ 4	$ 95	$ 0