Postretirement Benefits - Pension Plan Income (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024 USD ($) Participants	Jun. 30, 2023 USD ($)	Jun. 30, 2024 USD ($) Participants	Jun. 30, 2023 USD ($)
Retirement Benefits [Abstract]
Service cost for benefits earned	$ 8,641	$ 7,191	$ 17,292	$ 14,382
Interest cost on benefit obligation	13,163	12,548	26,308	25,096
Expected return on plan assets	(20,198)	(17,217)	(40,396)	(34,435)
Prior service cost amortization	397	361	786	723
Net actuarial gain amortization	(1,734)	(3,832)	(3,485)	(7,665)
Settlement gain (1)	(1,030)	0	(1,279)	0
Pension plan income	$ (761)	$ (949)	$ (774)	$ (1,899)
Defined benefit plan, net periodic benefit cost (credit) excluding service cost, statement of income or comprehensive income			Other income
Settlement accounting, number of participants receiving lump sum payments | Participants	3		3