Property, Plant and Equipment (Details) (USD $)	12 Months Ended
	Dec. 27, 2013	Dec. 28, 2012	Dec. 30, 2011
Property, Plant and Equipment, Net [Abstract]
Land and improvements	$ 16,506,000	$ 16,261,000
Buildings and improvements	118,460,000	115,774,000
Manufacturing equipment	222,810,000	214,073,000
Office, warehouse and automotive equipment	35,887,000	33,388,000
Additions in progress	14,224,000	9,571,000
Total property, plant and equipment	407,887,000	389,067,000
Accumulated depreciation	(256,170,000)	(237,523,000)
Net property, plant and equipment	151,717,000	151,544,000
Depreciation	$ 23,400,000	$ 22,200,000	$ 20,600,000