QUARTERLY FINANCIAL INFORMATION (UNAUDITED) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jul. 03, 2017
Net revenues	$ 331,035	$ 333,326	$ 333,532	$ 338,649	$ 344,750	$ 348,064	$ 350,221	$ 356,039	$ 1,336,542	$ 1,399,074	$ 1,059,574
Operating income (loss)	26,719	23,542	14,300	16,720	3,555	748	5,427	9,239	81,281	18,969	38,912
Net income (loss) attributable to common stockholders	$ (5,988)	257	$ (7,387)	$ (7,265)	$ (13,979)	$ (14,914)	$ (10,643)	$ (11,298)	$ (20,383)	$ (50,834)	$ 64,945
Basic and diluted earnings (loss) per share	$ (0.08)		$ (0.10)	$ (0.11)	$ (0.20)	$ (0.21)	$ (0.15)	$ (0.16)	$ (0.29)	$ (0.73)	$ 1.07
Severance costs incurred	$ 8,700				$ 5,700	$ 4,000
Subsidies revenue								$ 4,900
Transaction costs										$ 1,960	$ 33,650
Plan settlement	6,700								$ 6,700
Gains (Losses) on Extinguishment of Debt									$ 4,510
Incremental Term Loan Facility
Aggregate principal amount												$ 935,000
Senior Notes
Gains (Losses) on Extinguishment of Debt	$ 3,100	$ 1,100	$ 300