Property Plant and Equipment, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 446,530	$ 438,063
Less accumulated depreciation	(262,306)	(252,611)
Property, plant and equipment, net	184,224	185,452
Depreciation expense	28,600	27,700	$ 27,500
Land
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	15,292	15,163
Buildings
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	104,596	104,763
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	21,948	20,746
Machinery, office furniture and equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	287,269	269,417
Construction in process
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	17,425	27,974
ERP systems
Property, Plant and Equipment [Line Items]
Depreciation expense	3,700	3,300	3,900
Total expenses incurred	1,200	1,200	2,000
Total capital expenditures	4,100	3,600	4,100
Capital expenditures total to date	52,300
Assets held under capital lases
Property, Plant and Equipment [Line Items]
Depreciation expense	700	400	$ 300
Capital leased assets	11,400	7,200
Capital leases accumulated depreciation	$ 1,500	$ 800