LONG-TERM DEBT - Senior Secured Notes (Details) - USD ($)			3 Months Ended		6 Months Ended
	Apr. 05, 2018	Mar. 07, 2018	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	May 02, 2018	Feb. 05, 2018	Dec. 31, 2017	Nov. 30, 2017	Feb. 28, 2017
Line of Credit Facility [Line Items]
Loss on extinguishment of debt			$ 0	$ 0	$ 11,683,000	$ 12,458,000
Long-term debt			$ 626,833,000		$ 626,833,000				$ 706,225,000
Senior Notes | 12% Senior Secured Notes
Line of Credit Facility [Line Items]
Debt instrument, face amount										$ 135,000,000	$ 470,000,000
Stated interest rate (as percent)			12.00%		12.00%
Loss on extinguishment of debt		$ 11,700,000				$ 12,500,000
Debt issuance costs capitalized									18,300,000
Notice of redemption, amount	$ 37,700,000							$ 77,500,000
Redemption price, percentage of redemption amount (as percent)		112.00%
Long-term debt		$ 527,500,000	$ 512,136,000		$ 512,136,000				$ 585,823,000
Redemption price, percentage of excess cash flow (as percent)	50.00%	50.00%
Redemption period					125 days
Excess cash flow requirement, amount					$ 5,000,000
Excess cash flow, amount							$ 0