Contingent Liabilities and Commitments (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2023	Dec. 31, 2022
Site Contingency [Line Items]
Other	$ 8,640	$ 8,640	$ 4,011
Regulatory assets	1,991	1,991	13,565
Environmental assessment and remediation [Member]
Site Contingency [Line Items]
Accrued environmental assessment and remediation costs, total	$ 1,000	$ 1,000	$ 1,000
Environmental Loss Contingency, Statement of Financial Position [Extensible Enumeration]	Other, Other Liabilities, Noncurrent	Other, Other Liabilities, Noncurrent	Other, Other Liabilities, Noncurrent
Accrued environmental assessment and remediation costs, current	$ 100	$ 100	$ 100
Environmental Loss Contingency, Current, Statement of Financial Position [Extensible Enumeration]	Other	Other	Other
Accrued environmental assessment and remediation costs, noncurrent	$ 900	$ 900	$ 900
Environmental Loss Contingency, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other Liabilities, Noncurrent	Other Liabilities, Noncurrent	Other Liabilities, Noncurrent
Washington State Climate Commitment Act [Member]
Site Contingency [Line Items]
Other	$ 3,300	$ 3,300
Regulatory assets	17,100	17,100
Interest Income, Other	$ 200	$ 300