Business Segments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 23, 2012	Sep. 25, 2011	Sep. 23, 2012	Sep. 25, 2011	Dec. 25, 2011
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 193,926	$ 207,057	$ 611,436	$ 605,325
Property, plant and equipment, net	147,097		147,097		145,747
UNITED STATES
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	68,496	76,993	236,251	218,257
Property, plant and equipment, net	50,105		50,105		45,936
MEXICO
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	125,430	130,064	375,185	387,068
Property, plant and equipment, net	$ 96,992		$ 96,992		$ 99,811