PROPERTY, PLANT AND EQUIPMENT - Summary of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Total	$ 407,604	$ 402,742
Accumulated depreciation and amortization	(211,842)	(199,523)
Property, plant, and equipment, net	195,762	203,219
Land
Property, Plant and Equipment [Line Items]
Total	6,654	6,698
Buildings and leasehold improvements
Property, Plant and Equipment [Line Items]
Total	49,091	47,924
Machinery and equipment
Property, Plant and Equipment [Line Items]
Total	263,535	261,343
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Total	9,723	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	14,827	13,052
Automobiles
Property, Plant and Equipment [Line Items]
Total	4,993	5,070
Construction in progress
Property, Plant and Equipment [Line Items]
Total	$ 12,144	$ 12,613