v3.25.2
Employee and Retiree Benefit Plans - Components of Net Periodic Benefit Expense (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Pension Benefits        
Defined Benefit Plan Disclosure [Line Items]        
Service cost $ 1,683 $ 1,706 $ 3,366 $ 3,412
Interest cost 8,482 8,393 16,880 16,784
Expected return on plan assets (8,953) (8,359) (17,824) (16,716)
Estimated defined contribution provision 62 54 122 109
Amortization of prior service cost (credit) 492 579 983 1,158
Recognized actuarial loss (gain) 1,914 2,361 3,805 4,721
Total net periodic benefit expense 3,680 4,734 7,332 9,468
Other Postretirement Benefits        
Defined Benefit Plan Disclosure [Line Items]        
Service cost 84 135 168 270
Interest cost 708 782 1,416 1,564
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 loss (gain) (1,057) (812) (2,113) (1,624)
Total net periodic benefit expense $ (398) $ (28) $ (795) $ (56)