Property, Plant and Equipment (Schedule of Plant Property and Equipment) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Land	$ 16,726	$ 14,045
Buildings and improvements	141,082	132,105
Machinery and equipment	191,459	165,979
Office equipment	42,696	36,810
Property, plant and equipment, gross	391,963	348,939
Accumulated depreciation	(237,150)	(225,092)
Property, Plant and Equipment, Before Equipment in Process	154,813	123,847
Equipment in process	23,848	26,573
Total property, plant and equipment, net	$ 178,661	$ 150,420