Revenues Disaggregation of Revenue (Details) - USD ($) $ in Thousands	6 Months Ended		12 Months Ended
	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disaggregation of Revenue [Line Items]
Electric			$ 39,986	$ 38,345	$ 37,024
Operating revenues			491,528	498,853	488,243
ASUS construction			53,171	56,909	62,411
GSWC
Disaggregation of Revenue [Line Items]
Electric			0	0	18,647
Operating revenues			340,602	347,112	349,284
GSWC | Water:
Disaggregation of Revenue [Line Items]
Revenue from contract with customers			329,650	351,069	335,506
Operating revenues			340,602	347,112	330,637
GSWC | Water: | Tariff-based revenues
Disaggregation of Revenue [Line Items]
Revenue from contract with customers			324,838	345,562	329,670
GSWC | Water: | CPUC-approved surcharges (cost-recovery activities)
Disaggregation of Revenue [Line Items]
Revenue from contract with customers			2,461	3,280	3,736
GSWC | Water: | Other
Disaggregation of Revenue [Line Items]
Revenue from contract with customers			2,351	2,227	2,100
GSWC | Water: | Alternative revenue program
Disaggregation of Revenue [Line Items]
Regulated Operating Revenue			10,952	(3,957)	(4,869)
GSWC | Electric:
Disaggregation of Revenue [Line Items]
Operating revenues		$ 18,647		38,345	37,024
American States Utility Services | Contracted services:
Disaggregation of Revenue [Line Items]
Revenue from contract with customers			110,940	113,396	120,582
Operating revenues			110,940	113,396	120,582
American States Utility Services | Contracted services: | Water
Disaggregation of Revenue [Line Items]
Revenue from contract with customers			68,626	71,210	74,898
American States Utility Services | Contracted services: | Wastewater
Disaggregation of Revenue [Line Items]
Revenue from contract with customers			42,314	42,186	45,684
Golden State Water Company and Bear Valley Electric Service, Inc. | Franchisor
Disaggregation of Revenue [Line Items]
ASUS construction			4,000	4,200	3,800
Golden State Water Company and Bear Valley Electric Service, Inc. | Electric:
Disaggregation of Revenue [Line Items]
Revenue from contract with customers					35,969
Electric					(1,055)
Operating revenues				37,024	37,024
Golden State Water Company and Bear Valley Electric Service, Inc. | Electric: | Tariff-based revenues
Disaggregation of Revenue [Line Items]
Revenue from contract with customers					35,283
Golden State Water Company and Bear Valley Electric Service, Inc. | Electric: | CPUC-approved surcharges (cost-recovery activities)
Disaggregation of Revenue [Line Items]
Revenue from contract with customers					$ 686
BVESI | Electric:
Disaggregation of Revenue [Line Items]
Revenue from contract with customers			39,894	37,434
Electric			92	911
Operating revenues	$ 18,377		39,986	38,345
BVESI | Electric: | Tariff-based revenues
Disaggregation of Revenue [Line Items]
Revenue from contract with customers			39,750	37,124
BVESI | Electric: | CPUC-approved surcharges (cost-recovery activities)
Disaggregation of Revenue [Line Items]
Revenue from contract with customers			$ 144	$ 310