Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 613,988	$ 594,249
Less: accumulated depreciation	(412,825)	(404,629)
Property, plant and equipment, net	201,163	189,620
Land
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	5,215	4,275
Buildings
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	129,838	128,887
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	443,025	422,333
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 35,910	$ 38,753