Regulatory Matters - Schedule of Regulatory Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory Assets	$ 77,667	$ (25,454)
GSWC
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory Assets	60,866	(26,574)
GSWC | Other regulatory liabilities
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory Assets	(280)	(9,949)
BVES | Other regulatory liabilities
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory Assets	(8,180)	(8,005)
2022/2023 general rate case memorandum accounts (unbilled revenue) | GSWC
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory Assets	55,140	0
Water revenue adjustment mechanism, net of modified cost balancing account | GSWC
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory Assets	46,597	31,803
COVID-19 memorandum accounts | GSWC
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory Assets	3,543	3,478
Excess deferred income taxes | GSWC
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory Assets	(70,515)	(71,870)
Other regulatory assets | GSWC
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory Assets	26,381	19,964
Other regulatory assets | BVES
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory Assets	10,136	7,965
Derivative instrument memorandum account (Note 5) | BVES
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory Assets	(1,525)	(11,847)
Wildfire mitigation and other fire prevention related costs memorandum accounts | BVES
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory Assets	$ 16,370	$ 13,007