PROPERTY, PLANT AND EQUIPMENT - Long-Lived Assets by Geographical Area (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, excluding intangible assets	$ 194,339	$ 189,793
North America
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, excluding intangible assets	170,830	175,027
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, excluding intangible assets	$ 23,509	$ 14,766