Pension and Other Postretirement Obligations - Components of Net Periodic Benefit Costs (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 02, 2016	Sep. 27, 2015	Oct. 02, 2016	Sep. 27, 2015
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets	$ 0	$ 0	$ 0	$ 0
Pension Obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1,282	1,344	4,118	4,562
Interest cost	2,202	2,164	7,020	6,909
Expected return on plan assets	(2,931)	(3,202)	(9,339)	(9,515)
Amortization of prior service credit	(11)	(15)	(29)	(41)
Actuarial losses	659	1,349	2,067	3,923
Settlement loss	7,385	0	7,385	0
Net periodic benefit cost	8,586	1,640	11,222	5,838
Other Postretirement Obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	11	11	40	43
Interest cost	305	274	1,152	1,076
Amortization of prior service credit	(11)	(16)	(33)	(66)
Actuarial losses	29	107	260	359
Settlement loss	0	0	0	0
Net periodic benefit cost	$ 334	$ 376	$ 1,419	$ 1,412