Postretirement Benefits - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 29, 2012 Age	Dec. 31, 2011	Dec. 25, 2010
Pension and Other Postretirement Benefits Disclosure [Line Items]
Age plus years of service that employees were required to have as of October 1, 2001 in order to qualify for postretirement benefits in the future	65
Years of service that employees were required to have as of October 1, 2001 in order to qualify for postretirement benefits in the future	5 years
Minimum age that eligible employees are required to have in order to receive post retirement benefits	55
Minimum years of service that eligible employees are required to have in order to receive post retirement benefits	10 years
Actuarial losses recognized in other comprehensive earnings	$ 9,053,000	$ 9,459,000	$ 4,951,000
Actuarial losses recognized in other comprehensive earnings, tax effect	3,498,000	3,655,000	1,913,000
Benefit payments	$ 3,785,000	$ 3,146,000	$ 2,626,000
Accumulation of losses, maximum percentage threshold to amortize actuarial losses	10.00%