DEBT - Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Long-term debt	$ 502,863
First Lien Note Facility
Debt Instrument [Line Items]
Long-term debt	198,324	$ 0
Second Lien Note Facility
Debt Instrument [Line Items]
Long-term debt	85,694	0
2021 Notes Indenture
Debt Instrument [Line Items]
Long-term debt	197,363	$ 196,670
Carrying Value
Debt Instrument [Line Items]
Long-term debt	501,876
Carrying Value | First Lien Note Facility
Debt Instrument [Line Items]
Long-term debt	198,324
Carrying Value | Second Lien Note Facility
Debt Instrument [Line Items]
Long-term debt	85,694
Carrying Value | 2017 Warrants
Debt Instrument [Line Items]
Long-term debt	20,495
Carrying Value | 2021 Notes Indenture
Debt Instrument [Line Items]
Long-term debt	197,363
Fair Value | Markets for Identical Item (Level 1)
Debt Instrument [Line Items]
Long-term debt	0
Fair Value | Markets for Identical Item (Level 1) | First Lien Note Facility
Debt Instrument [Line Items]
Long-term debt	0
Fair Value | Markets for Identical Item (Level 1) | Second Lien Note Facility
Debt Instrument [Line Items]
Long-term debt	0
Fair Value | Markets for Identical Item (Level 1) | 2017 Warrants
Debt Instrument [Line Items]
Long-term debt	0
Fair Value | Markets for Identical Item (Level 1) | 2021 Notes Indenture
Debt Instrument [Line Items]
Long-term debt	0
Fair Value | Significant Other Observable Inputs (Level 2)
Debt Instrument [Line Items]
Long-term debt	204,056
Fair Value | Significant Other Observable Inputs (Level 2) | First Lien Note Facility
Debt Instrument [Line Items]
Long-term debt	0
Fair Value | Significant Other Observable Inputs (Level 2) | Second Lien Note Facility
Debt Instrument [Line Items]
Long-term debt	0
Fair Value | Significant Other Observable Inputs (Level 2) | 2017 Warrants
Debt Instrument [Line Items]
Long-term debt	20,495
Fair Value | Significant Other Observable Inputs (Level 2) | 2021 Notes Indenture
Debt Instrument [Line Items]
Long-term debt	183,561
Fair Value | Significant Unobservable Inputs (Level 3)
Debt Instrument [Line Items]
Long-term debt	301,428
Fair Value | Significant Unobservable Inputs (Level 3) | First Lien Note Facility
Debt Instrument [Line Items]
Long-term debt	200,578
Fair Value | Significant Unobservable Inputs (Level 3) | Second Lien Note Facility
Debt Instrument [Line Items]
Long-term debt	100,850
Fair Value | Significant Unobservable Inputs (Level 3) | 2017 Warrants
Debt Instrument [Line Items]
Long-term debt	0
Fair Value | Significant Unobservable Inputs (Level 3) | 2021 Notes Indenture
Debt Instrument [Line Items]
Long-term debt	$ 0