Schedule of Net Periodic Pension and Postretirement Cost (Benefit) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 28, 2014	Sep. 29, 2013	Sep. 28, 2014	Sep. 29, 2013
Defined Benefit Plan Disclosure
Actuarial gain				$ (1,359)
Defined Benefit Pension Plans
Defined Benefit Plan Disclosure
Service cost	761	871	2,368	2,557
Interest cost	3,650	3,350	11,102	10,001
Expected return on plan assets	(3,335)	(3,664)	(10,060)	(10,925)
Amortization of unrecognized prior service benefit	34	41	101	123
Actuarial gain			362	(1,123)
Total net periodic pension cost	1,110	598	3,873	633
Postretirement Benefit Plans
Defined Benefit Plan Disclosure
Service cost	15	19	44	56
Interest cost	84	86	252	257
Amortization of unrecognized prior service benefit	(150)	(150)	(449)	(449)
Actuarial gain			(247)	(236)
Total net periodic pension cost	$ (51)	$ (45)	$ (400)	$ (372)