Regulatory Matters - Narrative (Details)	1 Months Ended	3 Months Ended	9 Months Ended
	Sep. 30, 2022 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2022 USD ($)
Regulatory matters:
Regulatory asset not accruing carrying costs	$ (60,400,000)	$ (60,400,000)	$ (60,400,000)
Regulatory asset amount billed to customers as surcharges			$ 0
GSWC
Regulatory matters:
Number of unresolved issues for 2022-2024 water General Rate Case	3	3	3
Regulatory asset-CEMA	$ 5,100,000	$ 5,100,000	$ 5,100,000
Relief funding	9,500,000	9,500,000	9,500,000
GSWC | Cost of capital proceeding
Regulatory matters:
Revenue impact due to lower cost of debt		1,900,000	5,000,000
BVESI
Regulatory matters:
Regulatory asset-CEMA	454,000	454,000	454,000
Relief funding	321,000	321,000	321,000
Regulatory Asset -incremental vegetation management costs	7,900,000	7,900,000	7,900,000
Regulatory asset-Wildfire mitigation Plans ( WMP)	4,000,000	4,000,000	4,000,000
Regulatory asset CEMA - Storm	452,000	452,000	452,000
Excess deferred income taxes
Regulatory matters:
Regulatory asset not accruing carrying costs	(76,200,000)	(76,200,000)	(76,200,000)
Flow-through taxes, net
Regulatory matters:
Regulatory asset not accruing carrying costs	(3,700,000)	(3,700,000)	(3,700,000)
Pensions and other post-retirement obligations (Note 8)
Regulatory matters:
Regulatory asset not accruing carrying costs	(25,500,000)	(25,500,000)	(25,500,000)
Derivative unrealized gain (Note 5)
Regulatory matters:
Regulatory asset not accruing carrying costs	$ (7,600,000)	$ (7,600,000)	(7,600,000)
Water Revenue Adjustment Mechanism and Modified Cost Balancing Account
Regulatory matters:
Increase (decrease) in other regulatory assets			$ 20,700,000
Regulatory asset recovery periods			24 months
Water Revenue Adjustment Mechanism and Modified Cost Balancing Account | GSWC
Regulatory matters:
Commercial paper, term			90 days
COVID-19 memorandum accounts | BVESI
Regulatory matters:
Regulatory asset recovery periods	12 months