v3.26.1
Pension plans and other postretirement benefits - Net Periodic Defined Benefit Cost for Defined Benefit Plans (Detail) - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Pension Benefits    
Defined Benefit Plan Disclosure [Line Items]    
Service cost $ 2,000 $ 2,000
Interest cost on benefit obligation 23,000 27,000
Expected return on plan assets (43,000) (46,000)
Amortization of prior service credit and actuarial gains 0 (1,000)
Net periodic benefit $ (18,000) $ (18,000)
Defined benefit plan, net periodic benefit cost (credit) excluding service cost, statement of income or comprehensive income [extensible enumeration] Other costs of operations Other costs of operations
Other Postretirement Benefits    
Defined Benefit Plan Disclosure [Line Items]    
Service cost $ 0 $ 0
Interest cost on benefit obligation 1,000 1,000
Expected return on plan assets 0 0
Amortization of prior service credit and actuarial gains (1,000) (1,000)
Net periodic benefit $ 0 $ 0
Defined benefit plan, net periodic benefit cost (credit) excluding service cost, statement of income or comprehensive income [extensible enumeration] Other costs of operations Other costs of operations