Net Benefit Cost of Pension and Postretirement Benefit Plans (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 29, 2014	Jun. 30, 2013	Jun. 29, 2014	Jun. 30, 2013
Pension
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 447	$ 464	$ 897	$ 929
Interest cost	4,486	4,142	8,969	8,281
Expected return on plan assets	(6,264)	(5,774)	(12,524)	(11,544)
Net amortization and deferral	1,070	1,414	2,141	2,824
Net benefit expense (income)	(261)	246	(517)	490
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	138	161	276	325
Interest cost	596	542	1,193	1,541
Net amortization and deferral	27	202	53	932
Net benefit expense (income)	$ 761	$ 905	$ 1,522	$ 2,798