Pension and Other Postretirement Obligations - Components of Net Periodic Benefit Costs (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Apr. 01, 2012
Pension Obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1,687	$ 1,432
Interest cost	2,949	3,010
Expected return on plan assets	(3,406)	(3,165)
Amortization of prior service credit	(8)	(19)
Actuarial losses	1,668	1,492
Net periodic benefit cost	2,890	2,750
Other Postretirement Obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	34	32
Interest cost	526	588
Expected return on plan assets
Amortization of prior service credit	(28)	(29)
Actuarial losses	278	262
Net periodic benefit cost	$ 810	$ 853