Postretirement Benefits - Funding Policy/Funded Status (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Jan. 31, 2026
Postretirement benefits
Employer contributions	$ 42,331	$ 37,061
Net amount recognized in the Statements of Financial Position:
Funded status at end of year	(11,484)	(11,718)
Pension asset	24,137	21,311
Pension liabilities – due within one year	(2,211)	(4,959)
Pension liabilities – due after one year	(33,410)	(28,070)
Net amount recognized	$ (11,484)	(11,718)
Employee Pension Plan
Postretirement benefits
Funding target (as a percentage of the funding target liability)	100.00%
Employer contributions	$ 39,000	$ 33,000
Employee Pension Plan | Subsequent Event
Postretirement benefits
Employer contributions, 2026			$ 47,000