Pension and Other Postretirement Obligations - Components of Net Periodic Benefit Costs (Detail) - USD ($) $ in Thousands	3 Months Ended
	Apr. 01, 2018	Apr. 02, 2017
Pension Obligations
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1,133	$ 1,093
Interest cost	1,876	1,695
Expected return on plan assets	(2,520)	(2,361)
Amortization of prior service credit	(10)	(11)
Actuarial losses	665	587
Net periodic benefit cost	1,144	1,003
Other Postretirement Obligations
Defined Benefit Plan Disclosure [Line Items]
Service cost	13	13
Interest cost	264	327
Expected return on plan assets	0	0
Amortization of prior service credit	0	0
Actuarial losses	0	23
Net periodic benefit cost	$ 277	$ 363