INDEBTEDNESS - Estimated Fair Values of Debt Obligations (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2020	Sep. 30, 2019
Debt Instrument, Changes In Long-Term Debt [Roll Forward]
Interest rate PIK				$ 7,525	$ 0
Repayments of debt principal				(6,937)	$ (2,075)
Senior Notes
Debt Instrument [Line Items]
Total debt instruments	$ 1,172,086			1,172,086
Debt Instrument, Changes In Long-Term Debt [Roll Forward]
Total debt instruments, end of period	1,172,086			1,172,086
Senior Notes | First lien term loan
Debt Instrument [Line Items]
Total debt instruments	890,011			890,011
Debt Instrument, Changes In Long-Term Debt [Roll Forward]
Total debt instruments, end of period	890,011			890,011
Senior Notes | Second lien notes
Debt Instrument [Line Items]
Total debt instruments	282,075			282,075
Debt Instrument, Changes In Long-Term Debt [Roll Forward]
Total debt instruments, end of period	282,075			282,075
Senior Notes | Markets for Identical Item (Level 1)
Debt Instrument [Line Items]
Total debt instruments	0			0
Debt Instrument, Changes In Long-Term Debt [Roll Forward]
Total debt instruments, end of period	0			0
Senior Notes | Markets for Identical Item (Level 1) | First lien term loan
Debt Instrument [Line Items]
Total debt instruments	0			0
Debt Instrument, Changes In Long-Term Debt [Roll Forward]
Total debt instruments, end of period	0			0
Senior Notes | Markets for Identical Item (Level 1) | Second lien notes
Debt Instrument [Line Items]
Total debt instruments	0			0
Debt Instrument, Changes In Long-Term Debt [Roll Forward]
Total debt instruments, end of period	0			0
Senior Notes | Significant Other Observable Inputs (Level 2)
Debt Instrument [Line Items]
Total debt instruments	905,485			905,485
Debt Instrument, Changes In Long-Term Debt [Roll Forward]
Total debt instruments, end of period	905,485			905,485
Senior Notes | Significant Other Observable Inputs (Level 2) | First lien term loan
Debt Instrument [Line Items]
Total debt instruments	905,485			905,485
Debt Instrument, Changes In Long-Term Debt [Roll Forward]
Total debt instruments, end of period	905,485			905,485
Senior Notes | Significant Other Observable Inputs (Level 2) | Second lien notes
Debt Instrument [Line Items]
Total debt instruments	0			0
Debt Instrument, Changes In Long-Term Debt [Roll Forward]
Total debt instruments, end of period	0			0
Senior Notes | Significant Unobservable Inputs (Level 3)
Debt Instrument [Line Items]
Total debt instruments	321,172			321,172
Debt Instrument, Changes In Long-Term Debt [Roll Forward]
Total debt instruments, end of period	321,172			321,172
Senior Notes | Significant Unobservable Inputs (Level 3) | First lien term loan
Debt Instrument [Line Items]
Total debt instruments	0			0
Debt Instrument, Changes In Long-Term Debt [Roll Forward]
Total debt instruments, end of period	0			0
Senior Notes | Significant Unobservable Inputs (Level 3) | Second lien notes
Debt Instrument [Line Items]
Total debt instruments	321,172	$ 417,910	$ 339,371	321,172
Debt Instrument, Changes In Long-Term Debt [Roll Forward]
Total debt instruments, beginning of period	417,910	339,371	411,119	411,119
Change in fair value	20,737	78,539	(71,748)
Interest rate PIK	7,525
Repayments of debt principal	(125,000)
Total debt instruments, end of period	$ 321,172	$ 417,910	$ 339,371	$ 321,172