Pre-Production Costs Related to Long-Term Supply Arrangements (Details) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 25, 2012	Dec. 30, 2012
Unamortized Preproduction Costs [Abstract]
Preproduction costs	$ 54,098,000		$ 51,638,000
Accumulated amortization	(40,344,000)		(38,667,000)
Net preproduction costs	13,754,000		12,971,000
Deferred Revenue [Abstract]
Accrued expenses	5,509,000		5,688,000
Other non-current liabilities	3,137,000		3,443,000
Total deferred tooling revenues	8,646,000		9,131,000
Deferred Revenue, Revenue Recognized	$ 2,000,000	$ 2,100,000