Property, Plant and Equipment (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Property, plant and equipment [Abstract]
Total property, plant and equipment	$ 246,315,000	$ 241,950,000
Less accumulated depreciation	182,669,000	177,528,000
Total property, plant and equipment, net	63,646,000	64,422,000
Depreciation	12,000,000	11,200,000	11,300,000
Land, Buildings and Improvements [Member]
Property, plant and equipment [Abstract]
Total property, plant and equipment	44,930,000	44,750,000
Machinery and Equipment [Member]
Property, plant and equipment [Abstract]
Total property, plant and equipment	128,796,000	128,453,000
Tools, Dies and Auxiliary Equipment [Member]
Property, plant and equipment [Abstract]
Total property, plant and equipment	36,324,000	33,501,000
Furniture and Fixtures [Member]
Property, plant and equipment [Abstract]
Total property, plant and equipment	23,508,000	23,266,000
Leasehold Improvements [Member]
Property, plant and equipment [Abstract]
Total property, plant and equipment	6,840,000	6,397,000
Construction-In-Progress [Member]
Property, plant and equipment [Abstract]
Total property, plant and equipment	$ 5,917,000	$ 5,583,000