Postretirement Benefits - Pension Plan Cost (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Retirement Benefits [Abstract]
Service cost for benefits earned	$ 9,591	$ 8,862	$ 19,181	$ 17,724
Interest cost on benefit obligation	15,513	14,676	31,027	29,351
Expected return on plan assets	(19,889)	(20,069)	(39,778)	(40,138)
Prior service cost amortization	458	422	916	844
Net actuarial gain amortization	(68)	(655)	(135)	(1,309)
Settlement gain	0	0	0	(477)
Pension plan cost	$ 5,605	$ 3,236	$ 11,211	$ 5,995
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Excluding Service Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]			Other income