Contingent Liabilities and Commitments (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Site Contingency [Line Items]
Other	$ 14,320		$ 10,588
Regulatory assets	2,416		2,054
Environmental assessment and remediation [Member]
Site Contingency [Line Items]
Accrued environmental assessment and remediation costs, total	$ 1,000		$ 1,000
Environmental Loss Contingency, Statement of Financial Position [Extensible Enumeration]	Other, Other Liabilities, Noncurrent		Other, Other Liabilities, Noncurrent
Accrued environmental assessment and remediation costs, current	$ 200		$ 200
Environmental Loss Contingency, Current, Statement of Financial Position [Extensible Enumeration]	Other		Other
Accrued environmental assessment and remediation costs, noncurrent	$ 800		$ 800
Environmental Loss Contingency, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other Liabilities, Noncurrent		Other Liabilities, Noncurrent
Washington State Climate Commitment Act [Member]
Site Contingency [Line Items]
Other	$ 2,200		$ 3,700
Regulatory assets	27,900		$ 22,300
Interest Income, Other	$ 900	$ 100