PROPERTY, PLANT AND EQUIPMENT (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property, plant, and equipment	$ 457,045	$ 447,796
Accumulated depreciation and amortization	(286,736)	(255,845)
Property, plant and equipment, net	170,309	191,951
Finance lease, right-of-use asset, before accumulated amortization	5,700	5,600
Finance lease, right-of-use asset, accumulated amortization	900	500
Depreciation	31,500	34,400	$ 36,200
Land
Property, Plant and Equipment [Line Items]
Property, plant, and equipment	5,805	6,380
Buildings and leasehold improvements
Property, Plant and Equipment [Line Items]
Property, plant, and equipment	57,632	59,177
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property, plant, and equipment	302,886	284,020
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, plant, and equipment	11,450	10,946
Capitalized ERP system development costs
Property, Plant and Equipment [Line Items]
Property, plant, and equipment	45,917	46,637
Computers and computer software
Property, Plant and Equipment [Line Items]
Property, plant, and equipment	20,508	22,906
Automobiles
Property, Plant and Equipment [Line Items]
Property, plant, and equipment	4,518	4,642
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant, and equipment	$ 8,329	$ 13,088