Employee and Retiree Benefit Plans - Components of Net Periodic Benefit Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1,706	$ 1,650
Interest cost	8,391	8,507
Expected return on plan assets	(8,357)	(8,194)
Estimated defined contribution provision	55	0
Amortization of prior service cost (credit)	579	155
Recognized actuarial loss (gain)	2,360	2,401
Total net periodic benefit expense	4,734	4,519
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	135	132
Interest cost	782	874
Expected return on plan assets	0	0
Estimated defined contribution provision	0	0
Amortization of prior service cost (credit)	(133)	(133)
Recognized actuarial loss (gain)	(812)	(781)
Total net periodic benefit expense	$ (28)	$ 92