Regulatory Matters - Schedule of Regulatory Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Schedule of Regulatory Assets and Liabilities [Line Items]
Capital expenditure approved	$ (4,091)	$ (22,796)
GSWC
Schedule of Regulatory Assets and Liabilities [Line Items]
Capital expenditure approved	(4,561)	(24,082)
GSWC | Other regulatory liabilities
Schedule of Regulatory Assets and Liabilities [Line Items]
Capital expenditure approved	(5,543)	(2,680)
BVESI | Other regulatory liabilities
Schedule of Regulatory Assets and Liabilities [Line Items]
Capital expenditure approved	(9,121)	(8,189)
Water Revenue Adjustment Mechanism and Modified Cost Balancing Account | GSWC
Schedule of Regulatory Assets and Liabilities [Line Items]
Capital expenditure approved	30,869	13,326
Pensions and other post-retirement obligations (Note 8) | GSWC
Schedule of Regulatory Assets and Liabilities [Line Items]
Capital expenditure approved	24,406	25,212
COVID-19 memorandum accounts | GSWC
Schedule of Regulatory Assets and Liabilities [Line Items]
Capital expenditure approved	5,090	1,663
Excess deferred income taxes | GSWC
Schedule of Regulatory Assets and Liabilities [Line Items]
Capital expenditure approved	(72,296)	(73,000)
Flow-through taxes, net | GSWC
Schedule of Regulatory Assets and Liabilities [Line Items]
Capital expenditure approved	(3,429)	(5,552)
Other regulatory assets | GSWC
Schedule of Regulatory Assets and Liabilities [Line Items]
Capital expenditure approved	16,342	16,949
Other regulatory assets | BVESI
Schedule of Regulatory Assets and Liabilities [Line Items]
Capital expenditure approved	17,160	13,916
Derivative unrealized gain (Note 5) | BVESI
Schedule of Regulatory Assets and Liabilities [Line Items]
Capital expenditure approved	$ (7,569)	$ (4,441)