Employee and Retiree Benefit Plans - Components of Net Periodic Benefit Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1,650	$ 2,129	$ 3,300	$ 4,258
Interest cost	8,564	5,139	17,071	10,382
Expected return on plan assets	(8,254)	(7,954)	(16,448)	(16,092)
Estimated defined contribution provision	54	0	108	0
Amortization of prior service cost (credit)	155	579	310	1,179
Recognized actuarial loss (gain)	2,414	3,822	4,815	7,644
Total net periodic benefit expense	4,583	3,715	9,156	7,371
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	132	292	264	584
Interest cost	874	574	1,748	1,148
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)	(767)	(78)	(1,548)	(155)
Total net periodic benefit expense	$ 106	$ 655	$ 198	$ 1,311