RESTRUCTURING-RELATED ACTIVITIES - Schedule of Expected Future Restructuring Costs (Details) - GNP Restructuring Plan $ in Thousands	Dec. 31, 2017 USD ($)
Restructuring Cost and Reserve [Line Items]
Expected future restructuring costs	$ 6,756
Employee termination benefits
Restructuring Cost and Reserve [Line Items]
Expected future restructuring costs	4,074
Inventory impairments
Restructuring Cost and Reserve [Line Items]
Expected future restructuring costs	699
Other
Restructuring Cost and Reserve [Line Items]
Expected future restructuring costs	$ 1,983