Pensions and Other Post-retirement Benefits - Components of Net Periodic Benefit Cost (Credit) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 8,118	$ 9,214	$ 7,587
Interest cost	24,178	23,307	23,775
Expected return on plan assets	(48,030)	(42,832)	(39,639)
Amortization of prior service cost (credit)	650	142	161
Recognized net actuarial losses	1,091	1,103	186
Settlement/curtailment loss	17	919	15
Net periodic benefit cost	(13,976)	(8,147)	(7,915)
Other Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	124	176	214
Interest cost	1,104	994	1,090
Expected return on plan assets	0	0	0
Amortization of prior service cost (credit)	0	(184)	(245)
Recognized net actuarial losses	651	460	550
Settlement/curtailment loss	0	0	0
Net periodic benefit cost	$ 1,879	$ 1,446	$ 1,609