Pension Costs, which Include Costs for Qualified, Nonqualified and Union Plans (Detail) (Pension Plans, Defined Benefit, USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 25, 2012	Mar. 27, 2011
Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Service cost-benefits earned during the period	$ 2,032	$ 2,105
Interest cost on benefit obligation	39,654	42,872
Expected return on plan assets	(47,649)	(53,099)
Amortization of prior service cost	1,928	1,875
Amortization of actuarial loss	13,505	9,281
Net periodic cost (benefit)	$ 9,470	$ 3,034