Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 516,505	$ 486,170
Less: accumulated depreciation	(364,030)	(337,492)
Net property, plant and equipment	152,475	148,678
Land
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	3,299	2,684
Buildings
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	119,657	111,762
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	383,642	361,010
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 9,907	$ 10,714