PROPERTY, PLANT AND EQUIPMENT - Summary of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Total	$ 412,508	$ 402,742
Accumulated depreciation and amortization	(219,096)	(199,523)
Property, plant and equipment, net	193,412	203,219
Land
Property, Plant and Equipment [Line Items]
Total	6,299	6,698
Buildings and leasehold improvements
Property, Plant and Equipment [Line Items]
Total	49,736	47,924
Machinery and equipment
Property, Plant and Equipment [Line Items]
Total	270,795	261,343
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Total	10,103	9,405
Capitalized ERP system development costs
Property, Plant and Equipment [Line Items]
Total	46,637	46,637
Computers and computer software
Property, Plant and Equipment [Line Items]
Total	14,722	13,052
Automobiles
Property, Plant and Equipment [Line Items]
Total	5,048	5,070
Construction in progress
Property, Plant and Equipment [Line Items]
Total	$ 9,168	$ 12,613