Postretirement Benefits - Plan Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Fair value of plan assets:
Fair value of plan assets, beginning of year	$ 1,002,049	$ 996,879
Actual return on plan assets	90,357	8,034
Employer contributions	42,331	37,061
Benefits paid	(39,887)	(35,924)
Settlements	(3,252)	(4,001)
Fair value of plan assets, end of year	$ 1,091,598	$ 1,002,049