SEGMENT INFORMATION - Operating Income (loss) and Adjusted EBITDA by Segment (Details) - USD ($) $ 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
Segment Reporting Information [Line Items]
Operating (loss) income	$ 6,157	$ 24,726	$ 11,403	$ (3,641)	$ 17,885	$ 33,515	$ 23,262	$ (10,756)	$ 38,645	$ 63,906	$ (147,871)
North America
Segment Reporting Information [Line Items]
Operating (loss) income									48,967	78,102	(128,483)
Adjusted EBITDA									208,192	253,963	50,182
Europe
Segment Reporting Information [Line Items]
Operating (loss) income									(10,322)	(14,196)	(19,388)
Adjusted EBITDA									$ (5,895)	$ (6,457)	$ (11,019)