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, gross	$ 1,485,371	$ 1,412,594
Accumulated depreciation and amortization	(1,036,817)	(946,132)
Property, plant and equipment, net	448,554	466,462	$ 462,055
Depreciation expense	63,328	62,085	68,800
Software, amortization	2,100	2,400	3,200
Capital expenditures and purchased software	42,390	67,955	82,886
Unamortized software cost	4,800	5,300	6,900
Expenditures for maintenance and repairs	17,700	19,800	$ 19,400
Right-of-use assets included in Property, plant and equipment, net	8,976	15,689
Land and land improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 15,611	14,168
Useful life	25 years
Buildings
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 246,137	227,875
Buildings | Minimum
Property, Plant and Equipment [Line Items]
Useful life	15 years
Buildings | Maximum
Property, Plant and Equipment [Line Items]
Useful life	40 years
Right of use assets
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 10,971	16,686
Right of use assets | Minimum
Property, Plant and Equipment [Line Items]
Useful life	10 years
Right of use assets | Maximum
Property, Plant and Equipment [Line Items]
Useful life	15 years
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 1,076,092	1,020,348
Machinery and equipment | Minimum
Property, Plant and Equipment [Line Items]
Useful life	5 years
Machinery and equipment | Maximum
Property, Plant and Equipment [Line Items]
Useful life	15 years
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 8,638	8,126
Useful life	5 years
Computer and other equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 19,294	18,808
Computer and other equipment | Minimum
Property, Plant and Equipment [Line Items]
Useful life	3 years
Computer and other equipment | Maximum
Property, Plant and Equipment [Line Items]
Useful life	10 years
Software
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 62,400	60,995
Software | Minimum
Property, Plant and Equipment [Line Items]
Useful life	5 years
Software | Maximum
Property, Plant and Equipment [Line Items]
Useful life	8 years
Capital expenditures in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 46,228	$ 45,588