Pension and Postretirement Benefit Obligations - Components of Net Periodic Postretirement Benefit Cost (Detail) - Postretirement Benefits [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 01, 2017	Oct. 02, 2016	Oct. 01, 2017	Oct. 02, 2016
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 572	$ 350	$ 1,716	$ 1,050
Interest cost	910	778	2,732	2,333
Recognized net actuarial loss	648	587	1,944	1,762
Amortization of prior service cost	(745)	(840)	(2,237)	(2,520)
Net periodic pension cost	$ 1,385	$ 875	$ 4,155	$ 2,625