Regulatory Matters - Schedule of Regulatory Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory Assets	$ 77,569	$ 69,507
GSWC
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory Assets	51,548	45,729
GSWC | Other regulatory liabilities
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory Assets	(304)	(268)
BVES | Other regulatory liabilities
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory Assets	(8,848)	(6,578)
2022/2023 general rate case memorandum accounts (unbilled revenue) | GSWC
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory Assets	50,010	52,795
Water revenue adjustment mechanism, net of modified cost balancing account | GSWC
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory Assets	47,529	41,545
Deferred Income Tax Charge [Member] | GSWC
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory Assets	(69,878)	(70,189)
Other regulatory assets | GSWC
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory Assets	10,600	10,661
Other regulatory assets | BVES
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory Assets	7,795	7,697
Derivative instrument memorandum account (Note 5) | BVES
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory Assets	6,168	2,360
Wildfire mitigation and other fire prevention related costs memorandum accounts | BVES
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory Assets	18,638	17,716
Pension Costs and Other Postretirement Benefit Costs [Member] | GSWC
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory Assets	(4,861)	(4,867)
Low income rate assistance balancing accounts | GSWC
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory Assets	6,846	5,763
Asset retirement obligations | GSWC
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory Assets	7,258	7,099
Electric Supply Cost Adjustment Mechanism | BVES
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory Assets	2,268	2,583
Flowed-through deferred income taxes, net
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory Assets	5,600
Flowed-through deferred income taxes, net | GSWC
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory Assets	$ 4,348	$ 3,190