Contingent Liabilities and Commitments (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2023	Dec. 31, 2022
Site Contingency [Line Items]
Other Accrued Liabilities, Current	$ 7,141	$ 7,141	$ 4,011
Regulatory Asset, Current	1,855	1,855	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 Accrued Liabilities, Current, Other Liabilities, Noncurrent	Other Accrued Liabilities, Current, Other Liabilities, Noncurrent	Other Accrued Liabilities, Current, Other Liabilities, Noncurrent
Accrued environmental assessment and remediation costs, current	$ 100	$ 100	$ 100
Environmental Loss Contingency, Current, Statement of Financial Position [Extensible Enumeration]	Other Accrued Liabilities, Current	Other Accrued Liabilities, Current	Other Accrued Liabilities, Current
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 Accrued Liabilities, Current	$ 3,700	$ 3,700
Regulatory Asset, Current	11,300	11,300
Interest Income, Other	$ 100	$ 100