Business Segments 2 (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Segment Reporting [Abstract]
Total utility plant	$ 1,753,766	$ 1,626,004	$ 1,512,043
Other assets	280,608	274,979
Total Assets	2,034,374	1,900,983
Parent Company
Segment Reporting [Abstract]
Total utility plant	0	0	0
Total Assets	969,388	864,144
GSWC
Segment Reporting [Abstract]
Total utility plant	1,616,718	1,499,745
Total Assets	1,741,308	1,638,482
Segment Reporting Information [Line Items]
Depreciation on transportation equipment	382	379	353
Contracted services: | American States Utility Services
Segment Reporting [Abstract]
Total utility plant	$ 17,488	$ 19,751	$ 22,246