Pension and other postretirement benefits - Net benefit cost of pension and postretirement benefit plans (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Apr. 02, 2023
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Settlements	$ 138,139	$ 0
Pension
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	601	360
Interest cost	2,118	4,350
Expected return on plan assets	(2,201)	(6,310)
Net amortization and deferral	1,354	2,154
Settlements	138,139	0
Net benefit expense (income)	140,011	554
Other Benefits
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	0	0
Interest cost	109	186
Expected return on plan assets	0	0
Net amortization and deferral	(645)	(339)
Settlements	0	0
Net benefit expense (income)	$ (536)	$ (153)