Pensions and Other Post-employment Benefits (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 27, 2020	Mar. 29, 2019
Pension Benefits
Components of net periodic benefit cost
Service cost	$ 0	$ 1,340
Interest cost	1,215	1,557
Expected return on plan assets	(2,205)	(2,123)
Amortization of prior service benefit	0	120
Amortization of net loss (gain)	284	804
Total net benefit cost (benefit)	(706)	1,698
Other Benefits
Components of net periodic benefit cost
Service cost	15	17
Interest cost	53	100
Expected return on plan assets	0	0
Amortization of prior service benefit	(374)	(374)
Amortization of net loss (gain)	(83)	(23)
Total net benefit cost (benefit)	$ (389)	$ (280)