Property, Plant and Equipment (Schedule of Plant Property and Equipment) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property plant and equipment, gross	$ 537,785
Property plant and equipment, gross		$ 517,991
Accumulated depreciation	(341,119)
Accumulated depreciation	(341,119)	(317,414)
Property, plant and equipment, net	196,666	200,577
Equipment in process	63,580	42,182
Total property, plant and equipment, net	260,246
Total property, plant and equipment, net		242,759
Land
Property, Plant and Equipment [Line Items]
Property plant and equipment, gross	21,697
Property plant and equipment, gross		21,525
Buildings and improvements
Property, Plant and Equipment [Line Items]
Property plant and equipment, gross	165,968
Property plant and equipment, gross		175,279
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property plant and equipment, gross	281,771
Property plant and equipment, gross		256,301
Office equipment
Property, Plant and Equipment [Line Items]
Property plant and equipment, gross	$ 68,349
Property plant and equipment, gross		$ 64,886