Pensions and Other Post-employment Benefits (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 29, 2018	Jun. 30, 2017	Jun. 29, 2018	Jun. 30, 2017
Pension Benefits [Member]
Components of net periodic benefit cost
Service cost	$ 1,674	$ 1,777	$ 3,348	$ 3,496
Interest cost	2,397	2,370	4,794	4,726
Expected return on plan assets	(3,697)	(3,378)	(7,394)	(6,743)
Amortization of prior service benefit	(30)	(73)	(61)	(194)
Amortization of net loss	1,959	1,611	3,919	3,198
Net periodic benefit cost (benefit)	2,303	2,307	4,606	4,483
Other Benefits [Member]
Components of net periodic benefit cost
Service cost	28	23	56	46
Interest cost	99	99	198	198
Expected return on plan assets	0	0	0	0
Amortization of prior service benefit	(374)	(374)	(749)	(748)
Amortization of net loss	0	0	0	0
Net periodic benefit cost (benefit)	$ (247)	$ (252)	$ (495)	$ (504)