v3.25.1
Retirement Plans and Other Postretirement Benefits - Schedule of Net Periodic Benefit Costs and Portion including Portion Charged to Expense (Details) - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Net periodic benefit costs and the portion of these costs charged to expense    
Portion of costs (credits) charged to expense $ (2,958) $ (11,568)
Pension Plans    
Net periodic benefit costs and the portion of these costs charged to expense    
Service cost-benefits earned during the period 10,949 10,631
Interest cost on benefit obligation 38,976 37,236
Expected return on plan assets (44,547) (46,983)
Prior service credit 0 0
Net actuarial loss (gain) 12,118 10,944
Net periodic benefit costs (credits) 17,496 11,828
Portion of costs (credits) charged to expense 10,461 6,337
Other Benefits Plans    
Net periodic benefit costs and the portion of these costs charged to expense    
Service cost-benefits earned during the period 1,982 2,459
Interest cost on benefit obligation 5,102 5,613
Expected return on plan assets (12,142) (11,709)
Prior service credit (1,265) (9,447)
Net actuarial loss (gain) (2,899) (2,080)
Net periodic benefit costs (credits) (9,222) (15,164)
Portion of costs (credits) charged to expense $ (6,873) $ (11,306)