Regulatory Matters - Schedule of Regulatory Liabilities and Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets	$ 54,679	$ 69,507
GSWC
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets	18,173	45,729
GSWC | Excess deferred income taxes (Note 11)
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory liability	(63,682)	(70,189)
GSWC | Pensions and other post-retirement obligations (Note 12)
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory liability	(25,179)	(4,867)
GSWC | Other regulatory liabilities
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory liability	(608)	(268)
GSWC | 2022/2023 general rate case memorandum accounts (unbilled revenue)
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory assets	37,711	52,795
Net regulatory assets	37,700
GSWC | Water revenue adjustment mechanism, net of the modified cost balancing account
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory assets	29,738	41,545
Net regulatory assets	29,700
GSWC | Asset retirement obligations (Note 1)
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory assets	7,501	7,099
GSWC | Flowed-through deferred income taxes, net (Note 11)
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory assets	12,506	3,190
GSWC | Low income rate assistance balancing accounts
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory assets	8,834	5,763
GSWC | Other Regulatory Assets
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory assets	11,352	10,661
BVES
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets	36,506	23,778
BVES | Other regulatory liabilities
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory liability	(5,628)	(6,578)
BVES | Other Regulatory Assets
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory assets	8,853	10,280
BVES | 2023/2024 general rate case memorandum accounts (unbilled revenue)
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory assets	9,777	0
Net regulatory assets	9,800
BVES | Derivative instrument memorandum account (Note 5)
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory assets	8,823	2,360
BVES | Wildfire mitigation and other fire prevention related costs memorandum accounts
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory assets	$ 14,681	$ 17,716