Net Benefit Cost of Pension and Postretirement Benefit Plans (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 30, 2014	Mar. 31, 2013
Pension
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 450	$ 465
Interest cost	4,483	4,139
Expected return on plan assets	(6,260)	(5,770)
Net amortization and deferral	1,071	1,410
Net benefit cost	(256)	244
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	138	164
Interest cost	597	999
Expected return on plan assets	0
Net amortization and deferral	26	730
Net benefit cost	$ 761	$ 1,893