Net Benefit Cost of Pension and Postretirement Benefit Plans (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jul. 01, 2012	Jun. 30, 2013	Jul. 01, 2012
Pension
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 464	$ 711	$ 929	$ 1,389
Interest cost	4,142	4,125	8,281	8,251
Expected return on Plan assets	(5,774)	(5,042)	(11,544)	(10,085)
Net amortization and deferral	1,414	1,604	2,824	3,210
Settlement charge		(124)		(124)
Curtailment charge		111		111
Net benefit cost	246	1,385	490	2,752
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	161	158	325	316
Interest cost	542	473	1,541	946
Net amortization and deferral	202	122	932	245
Net benefit cost	$ 905	$ 753	$ 2,798	$ 1,507