Summary of Changes in Fair Value of Plan's Level 3 Assets (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 29, 2012	Dec. 31, 2011
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]
Ending balance	$ 209,422	$ 191,571
Plan Assets
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]
Beginning Balance	20,304	26,952
Net realized and unrealized gains/(losses)	1,679	(1,695)
Net purchases, issuances and settlements	(605)	(5,314)
Net transfer in or (out) of Level 3		361
Ending balance	21,378	20,304
Common Collective Trust Funds | Plan Assets
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]
Beginning Balance	1,439	1,652
Net realized and unrealized gains/(losses)	74	171
Net purchases, issuances and settlements	(508)	(384)
Ending balance	1,005	1,439
Limited Partnership | Plan Assets
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]
Beginning Balance	365	4
Net realized and unrealized gains/(losses)	(15)
Net purchases, issuances and settlements	(176)
Net transfer in or (out) of Level 3		361
Ending balance	174	365
Unallocated annuity contracts | Plan Assets
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]
Beginning Balance	11,149	10,762
Net purchases, issuances and settlements	153	387
Ending balance	11,302	11,149
Interest in 103-12 Investments | Plan Assets
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]
Beginning Balance	7,351	14,534
Net realized and unrealized gains/(losses)	1,620	(1,866)
Net purchases, issuances and settlements	(74)	(5,317)
Ending balance	$ 8,897	$ 7,351