Pension Plans and Other Postretirement Benefits (Details-6) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan, Expected Future Employer Contributions [Abstract]
Expected employer contributions, 2024	$ 0
Cash contributions to pension and other postretirement plans	(7,747)	$ (7,308)	$ (6,935)
Pension Benefits [Member]
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
Defined benefit plan expected future benefit payments, 2024	21,650
Defined benefit plan expected future benefit payments, 2025	21,884
Defined benefit plan expected future benefit payments, 2026	22,155
Defined benefit plan expected future benefit payments, 2027	22,516
Defined benefit plan expected future benefit payments, 2028	22,760
Defined benefit plan expected future benefit payments, 2029-2033	116,273
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
Defined benefit plan expected future benefit payments, 2024	5,489
Defined benefit plan expected future benefit payments, 2025	5,707
Defined benefit plan expected future benefit payments, 2026	5,665
Defined benefit plan expected future benefit payments, 2027	5,607
Defined benefit plan expected future benefit payments, 2028	5,578
Defined benefit plan expected future benefit payments, 2029-2033	26,608
Medicare Part D Subsidies
Expected Medicare Part D Subsidies, 2024	(368)
Expected Medicare Part D Subsidies, 2025	(402)
Expected Medicare Part D Subsidies, 2026	(449)
Expected Medicare Part D Subsidies, 2027	(489)
Expected Medicare Part D Subsidies, 2028	(519)
Expected Medicare Part D Subsidies, 2029-2033	(2,971)
Defined benefit plan expected net future benefit payments, 2024	5,121
Defined benefit plan expected net future benefit payments, 2025	5,305
Defined benefit plan expected net future benefit payments, 2026	5,216
Defined benefit plan expected net future benefit payments, 2027	5,118
Defined benefit plan expected net future benefit payments, 2028	5,059
Defined benefit plan expected net future benefit payments, 2029-2033	$ 23,637