Pension and Other Post-retirement Benefits (Detail) - Accumulated other comprehensive income Unrecognized in Net Periodic Benefit Cost (USD $) In Thousands, unless otherwise specified	Dec. 29, 2012	Dec. 31, 2011
Unrecognized prior service credits
Unrecognized actuarial losses (gains)	25,747	24,110
Unrecognized net periodic cost (benefit)	25,747	24,110
Less deferred taxes (benefit)	(10,042)	(9,403)
Total	15,705	14,707
Pension Plans, Defined Benefit [Member]
Unrecognized prior service credits
Unrecognized actuarial losses (gains)	26,116	24,368
Unrecognized net periodic cost (benefit)	26,116	24,368
Less deferred taxes (benefit)	(10,186)	(9,504)
Total	15,930	14,864
Other Postretirement Benefit Plans, Defined Benefit [Member]
Unrecognized prior service credits
Unrecognized actuarial losses (gains)	(369)	(258)
Unrecognized net periodic cost (benefit)	(369)	(258)
Less deferred taxes (benefit)	144	101
Total	$ (225)	$ (157)