RESTATEMENT OF CONSOLIDATED FINANCIAL STATEMENTS (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
CURRENT LIABILITIES:
Accounts payable and accrued expenses	$ 29,817				$ 33,991				$ 29,817	$ 33,991
Long-term debt, current portion	1,167,487				181,023				1,167,487	181,023
Less unamortized discount and debt financing costs	(45,999)								(45,999)
Long-term debt, current portion less unamortized discount and debt financing costs	1,121,488				181,023				1,121,488	181,023
Derivative financial instruments - current	852				1,552				852	1,552
Total current liabilities	1,152,157				216,566				1,152,157	216,566
NONCURRENT LIABILITIES:
Long-term debt	194,339				1,400,928				194,339	1,400,928
Less unamortized discount and debt financing costs	(3,780)				(63,146)				(3,780)	(63,146)
Long-term debt less unamortized discount and debt financing costs	190,559				1,337,782				190,559	1,337,782
Other noncurrent liabilities	1,175				910				1,175	910
Total noncurrent liabilities	191,734				1,338,692				191,734	1,338,692
TOTAL LIABILITIES	1,343,891				1,555,258				1,343,891	1,555,258
Net (loss) / income	(45,392)	$ (67,468)	$ (82,545)	$ 26,864	5,804	$ (37,351)	$ 37,995	$ 60,858	(168,541)	67,306	$ 129,569
Accumulated deficit	264,656				$ 96,115				264,656	$ 96,115
Previously reported
CURRENT LIABILITIES:
Accounts payable and accrued expenses	29,817								29,817
Long-term debt, current portion	120,336								120,336
Long-term debt, current portion less unamortized discount and debt financing costs	120,336								120,336
Derivative financial instruments - current	852								852
Total current liabilities	151,005								151,005
NONCURRENT LIABILITIES:
Long-term debt	1,241,490								1,241,490
Less unamortized discount and debt financing costs	(49,779)								(49,779)
Long-term debt less unamortized discount and debt financing costs	1,191,711								1,191,711
Other noncurrent liabilities	1,175								1,175
Total noncurrent liabilities	1,192,886								1,192,886
TOTAL LIABILITIES	1,343,891								1,343,891
Adjustments
CURRENT LIABILITIES:
Long-term debt, current portion	1,047,151								1,047,151
Less unamortized discount and debt financing costs	(45,999)								(45,999)
Long-term debt, current portion less unamortized discount and debt financing costs	1,001,152								1,001,152
Total current liabilities	1,001,152								1,001,152
NONCURRENT LIABILITIES:
Long-term debt	(1,047,151)								(1,047,151)
Less unamortized discount and debt financing costs	45,999								45,999
Long-term debt less unamortized discount and debt financing costs	(1,001,152)								(1,001,152)
Total noncurrent liabilities	$ (1,001,152)								$ (1,001,152)