Pension and Postretirement Benefit Obligations - Components of Net Periodic Postretirement Benefit Cost (Detail) - Net Postretirement Benefits Activity - USD ($) $ in Thousands	3 Months Ended
	Mar. 29, 2020	Mar. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 376	$ 389
Interest cost	503	693
Recognized net actuarial loss	88	196
Amortization of prior service cost	0	(324)
Net periodic pension/postretirement benefit cost	$ 967	$ 954