Business Segments (Details) $ in Thousands	6 Months Ended		12 Months Ended
	Dec. 31, 2020 USD ($)	Jun. 30, 2020 USD ($)	Dec. 31, 2022 USD ($) segment	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Details of reportable segment
Operating revenues			$ 491,528	$ 498,853	$ 488,243
Operating Income			126,636	140,977	130,499
Interest expense, net			(24,701)	(21,341)	(20,730)
Net utility plant	$ 1,512,043		1,753,766	1,626,004	1,512,043
Depreciation and amortization expense			41,315	39,596	36,850
Income tax benefit			23,664	30,423	28,197
Capital additions			$ 166,240	144,515	130,423
Parent Company
Details of reportable segment
Number of reportable segments | segment			3
Operating revenues			$ 0	0	0
Operating Income			(8)	(9)	(9)
Interest expense, net			(2,343)	(791)	(330)
Net utility plant	0		0	0	0
Depreciation and amortization expense			0	0	0
Income tax benefit			(597)	(81)	(208)
Capital additions			$ 0	0	0
GSWC
Details of reportable segment
Number of reportable segments | segment			1
Operating revenues			$ 340,602	347,112	349,284
Operating Income			92,455	107,573	102,896
Net utility plant			1,616,718	1,499,745
Depreciation and amortization expense			34,805	33,384	32,184
Income tax benefit			16,346	22,095	21,704
GSWC | Water Service Utility Operations
Details of reportable segment
Operating revenues			340,602	347,112	330,637
Operating Income			92,455	107,573	97,896
Interest expense, net			(21,659)	(21,046)	(20,312)
Net utility plant	1,400,489		1,616,718	1,499,745	1,400,489
Depreciation and amortization expense			34,805	33,384	30,969
Income tax benefit			16,346	22,095	20,515
Capital additions			146,730	123,526	107,355
GSWC | Electric:
Details of reportable segment
Operating revenues		$ 18,647		38,345	37,024
Operating Income				10,738	10,303
Interest expense, net				(141)	(584)
Net utility plant	89,308			106,508	89,308
Depreciation and amortization expense				2,572	2,479
Income tax benefit				2,975	2,689
Capital additions				19,859	18,393
American States Utility Services | Contracted services:
Details of reportable segment
Operating revenues			110,940	113,396	120,582
Operating Income			22,449	22,675	22,309
Interest expense, net			132	637	496
Net utility plant	22,246		17,488	19,751	22,246
Depreciation and amortization expense			3,718	3,640	3,402
Income tax benefit			5,476	5,434	5,201
Capital additions			$ 1,441	1,130	$ 4,675
Period of Fixed Price Contracts to Operate and Maintain Water Systems at Various Military Bases			50 years
BVESI | Electric:
Details of reportable segment
Operating revenues	$ 18,377		$ 39,986	38,345
Operating Income			11,740
Interest expense, net			(831)
Net utility plant			119,560
Depreciation and amortization expense			2,792
Income tax benefit				$ 2,439
Capital additions			$ 18,069