Postretirement Benefits - Pension Plan Cost (Income) (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024 USD ($) participant	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($) participant	Sep. 30, 2023 USD ($)
Retirement Benefits [Abstract]
Service cost for benefits earned	$ 8,628	$ 7,190	$ 25,920	$ 21,572
Interest cost on benefit obligation	13,195	12,548	39,503	37,644
Expected return on plan assets	(20,199)	(17,217)	(60,595)	(51,652)
Prior service cost amortization	413	362	1,199	1,085
Net actuarial gain amortization	(1,695)	(3,833)	(5,180)	(11,498)
Settlement gain	(59)	0	(1,338)	0
Pension plan cost (income)	$ 283	$ (950)	$ (491)	$ (2,849)
Settlement accounting, number of participants receiving lump sum payments | participant	4		4
Defined benefit plan, net periodic benefit cost (credit) excluding service cost, statement of income or comprehensive income			Other income