v3.26.1
Employee and Retiree Benefit Plans - Schedule of Components of Net Periodic Benefit Expense (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Pension Benefits        
Defined Benefit Plan Disclosure [Line Items]        
Service cost $ 1,865 $ 1,683 $ 3,730 $ 3,366
Interest cost 7,752 8,482 15,504 16,880
Expected return on plan assets (8,792) (8,953) (17,584) (17,824)
Estimated defined contribution provision 70 62 140 122
Amortization of prior service cost (credit) 432 492 864 983
Recognized actuarial (gain) loss 1,644 1,914 3,288 3,805
Total net periodic benefit cost (credit) 2,971 3,680 5,942 7,332
Other Postretirement Benefits        
Defined Benefit Plan Disclosure [Line Items]        
Service cost 102 84 204 168
Interest cost 750 708 1,500 1,416
Expected return on plan assets 0 0 0 0
Estimated defined contribution provision 0 0 0 0
Amortization of prior service cost (credit) (133) (133) (266) (266)
Recognized actuarial (gain) loss (387) (1,057) (774) (2,113)
Total net periodic benefit cost (credit) $ 332 $ (398) $ 664 $ (795)