Schedule of Net Periodic Pension and Postretirement Cost (Benefit) (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
Defined Benefit Plan Disclosure
Actuarial gain				$ (1,359)
Defined Benefit Pension Plans
Defined Benefit Plan Disclosure
Service cost	811	852	1,607	1,686
Interest cost	3,732	3,281	7,452	6,651
Expected return on plan assets	(3,384)	(3,631)	(6,725)	(7,261)
Amortization of unrecognized prior service benefit	34	41	67	82
Actuarial gain	362	(1,123)	362	(1,123)
Total net periodic pension/ postretirement cost (benefit)	1,555	(580)	2,763	35
Postretirement Benefit Plans
Defined Benefit Plan Disclosure
Service cost	17	21	29	37
Interest cost	82	84	168	171
Amortization of unrecognized prior service benefit	(150)	(150)	(299)	(299)
Actuarial gain	(247)	(236)	(247)	(236)
Total net periodic pension/ postretirement cost (benefit)	$ (298)	$ (281)	$ (349)	$ (327)