Pensions and Other Post-employment Benefits (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Oct. 01, 2021	Sep. 30, 2022	Oct. 01, 2021
Components of net periodic benefit (credit) cost
Contributions by employer	$ 0	$ 0	$ 0	$ 0
Pension Benefits
Components of net periodic benefit (credit) cost
Service cost	281,000	410,000	891,000	1,284,000
Interest cost	1,203,000	1,045,000	3,639,000	3,141,000
Expected return on plan assets	(2,380,000)	(2,459,000)	(7,158,000)	(7,407,000)
Amortization of prior service (benefit) cost	(19,000)	(18,000)	(57,000)	(60,000)
Amortization of net loss (gain)	410,000	565,000	1,260,000	1,719,000
Net periodic benefit (credit) cost	(505,000)	(457,000)	(1,425,000)	(1,323,000)
Settlements	0	0	0	0
Total net benefit (credit) cost	(505,000)	(457,000)	(1,425,000)	(1,323,000)
Other Benefits
Components of net periodic benefit (credit) cost
Service cost	21,000	20,000	63,000	60,000
Interest cost	39,000	29,000	117,000	87,000
Expected return on plan assets	0	0	0	0
Amortization of prior service (benefit) cost	(374,000)	(374,000)	(1,122,000)	(1,122,000)
Amortization of net loss (gain)	(68,000)	(69,000)	(204,000)	(207,000)
Net periodic benefit (credit) cost	(382,000)	(394,000)	(1,146,000)	(1,182,000)
Settlements	0	0	0	0
Total net benefit (credit) cost	$ (382,000)	$ (394,000)	$ (1,146,000)	$ (1,182,000)