Business Segments - Narrative (Details) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2023 USD ($) segment item	Mar. 31, 2022 USD ($)	Dec. 31, 2022 USD ($)
GSWC
Details of reportable segment
Number of reportable segments | item	1
Golden State Water Company and Bear Valley Electric Service Inc.
Details of reportable segment
Public Utilities Property Plant and Equipment Depreciation on Transportation Equipment | $	$ 368	$ 94	$ 212
Parent Company
Details of reportable segment
Number of reportable segments | segment	3