PROPERTY, PLANT AND EQUIPMENT - (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Total	$ 442,331		$ 447,796
Accumulated depreciation and amortization	(257,884)		(255,845)
Property, plant and equipment, net	184,447		191,951
Assets under finance leases	5,600		5,600
Accumulated amortization for assets under finance leases	600		500
Depreciation expense	8,100	$ 8,600
Land
Property, Plant and Equipment [Line Items]
Total	6,343		6,380
Buildings and leasehold improvements
Property, Plant and Equipment [Line Items]
Total	58,500		59,177
Machinery and equipment
Property, Plant and Equipment [Line Items]
Total	282,640		284,020
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Total	10,903		10,946
Capitalized Enterprise Resource Planning 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	18,430		22,906
Vehicles
Property, Plant and Equipment [Line Items]
Total	4,426		4,642
Construction in progress
Property, Plant and Equipment [Line Items]
Total	$ 14,452		$ 13,088