RESTRUCTURING CHARGES - Schedule of Accrued Restructuring and Severance Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accrued restructuring and severance costs rollforward
Balance at beginning of period	$ 9,483
Net accruals	20,601	$ 13,247	$ 0
Non-cash additions/(reductions)	(5,657)	0
Cash paid	(22,849)	(3,764)
Balance at end of period	1,578	9,483
Employee separation costs
Accrued restructuring and severance costs rollforward
Balance at beginning of period	9,483
Net accruals	16,852	13,247
Non-cash additions/(reductions)	(2,146)	0
Cash paid	(22,611)	(3,764)
Balance at end of period	1,578	9,483
Other exit costs
Accrued restructuring and severance costs rollforward
Balance at beginning of period	0
Net accruals	3,749	0
Non-cash additions/(reductions)	(3,511)	0
Cash paid	(238)	0
Balance at end of period	$ 0	$ 0