Components of Net Periodic Benefit Cost (Income) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jul. 02, 2011	Jun. 30, 2012	Jul. 02, 2011
Pension benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 3,761	$ 3,131	$ 7,522	$ 6,261
Interest cost	8,087	8,225	16,174	16,450
Expected return on plan assets	(7,844)	(7,964)	(15,688)	(15,927)
Recognized net actuarial loss (gains)	2,577	972	5,154	1,943
Net periodic benefit cost (income)	6,581	4,364	13,162	8,727
Post-retirement
Defined Benefit Plan Disclosure [Line Items]
Service cost	55	45	110	90
Interest cost	422	472	844	944
Amortization of prior year service cost (benefit)	(6)	(7)	(12)	(14)
Recognized net actuarial loss (gains)	(602)	(827)	(1,204)	(1,653)
Net periodic benefit cost (income)	$ (131)	$ (317)	$ (262)	$ (633)