Property, Plant and Equipment (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Schedule of Property, plant and equipment [Abstract]
Land	$ 4,312	$ 4,221
Buildings and Improvements	108,460	92,307
Machinery and equipment	398,490	364,370
Furniture and fixtures	1,884	1,813
Construction in progress	16,808	21,382
Total	529,954	484,093
Accumulated depreciation	(357,988)	(332,278)
Net	171,966	151,815
Depreciation expense	22,218	21,528	22,822
Total capital expenditures	$ 41,600	$ 29,407