Property, Plant and Equipment (Schedule of Plant Property and Equipment) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
Land	$ 15,855	$ 16,726
Buildings and improvements	138,493	141,082
Machinery and equipment	220,238	191,459
Office equipment	54,013	42,696
Property, plant and equipment, gross	428,599	391,963
Accumulated depreciation	(259,178)	(237,150)
Property, plant and equipment, net	169,421	154,813
Equipment in process	7,495	23,848
Total property, plant and equipment, net	$ 176,916	$ 178,661