Pension and Postretirement Benefit Obligations - Components of Net Periodic Pension Cost (Detail) - Pension Plans [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Oct. 01, 2017	Sep. 30, 2018	Oct. 01, 2017
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1,412	$ 150	$ 4,237	$ 450
Interest cost	2,856	2,978	8,568	8,936
Expected return on plan assets	(3,853)	(3,399)	(11,557)	(10,197)
Recognized net actuarial loss	934	807	2,800	2,421
Amortization of prior service cost	6	7	18	21
Net periodic benefit cost	$ 1,355	$ 543	$ 4,066	$ 1,631