Postretirement Benefits - Funding Policy/Funded Status (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Postretirement benefits
Employer contributions during fiscal year	$ 37,061	$ 96,222
Net amount recognized in the Statements of Financial Position:
Funded status at end of year	(11,718)	3,325
Pension asset	21,311	34,320
Pension liabilities – due within one year	(4,959)	(4,735)
Pension liabilities – due after one year	(28,070)	(26,260)
Net amount recognized	$ (11,718)	3,325
Employee Pension Plan
Postretirement benefits
Funding target (as a percentage of the funding target liability)	100.00%
Employer contributions during fiscal year	$ 33,000	$ 95,000
Employer contributions, 2024	$ 39,000