Employee Benefit Plans - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Increase (Decrease) in Regulatory Assets and Liabilities	$ 35,863	$ 5,713
GSWC
Defined Benefit Plan Disclosure [Line Items]
Increase (Decrease) in Regulatory Assets and Liabilities	34,059	5,135
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Expected contributions in current fiscal year	3,000
Increase (Decrease) in Regulatory Assets and Liabilities	92	$ 0
Pension Benefits | GSWC
Defined Benefit Plan Disclosure [Line Items]
Regulatory adjustment — deferred	(1,227)
Pension Benefits | BVES
Defined Benefit Plan Disclosure [Line Items]
Regulatory adjustment — deferred	(574)
Pension Benefits | Water: | GSWC
Defined Benefit Plan Disclosure [Line Items]
Increase (Decrease) in Regulatory Assets and Liabilities	$ (92)