Business Segments - Schedule of Business Segments (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Details of reportable segment
Operating revenues	$ 157,400		$ 122,607	$ 318,823	$ 231,177
Operating income (loss)	58,945		34,317	110,110	58,682
Interest expense (income), net	8,925		5,872	16,542	11,195
Net property, plant and equipment	1,814,061		1,683,487	1,814,061	1,683,487	$ 1,753,766
Depreciation and amortization	10,258		10,171	21,461	20,285
Income tax expense	13,204		6,205	23,956	10,666
Capital additions	39,312		41,382	88,649	76,552
AWR | Intersegment Eliminations
Details of reportable segment
Operating revenues	0		0	0	0
Operating income (loss)	(36)		(3)	(37)	(5)
Interest expense (income), net	1,429		361	2,752	561
Net property, plant and equipment	0		0	0	0
Depreciation and amortization	0		0	0	0
Income tax expense	(483)		(221)	(1,027)	(345)
Capital additions	0		0	0	0
GOLDEN STATE WATER COMPANY
Details of reportable segment
Operating revenues	116,908		90,856	229,620	164,762
Operating income (loss)	50,524		27,711	90,763	44,710
Net property, plant and equipment	1,666,700			1,666,700		$ 1,616,718
Depreciation and amortization	8,674		8,553	18,280	17,098
Income tax expense	11,934		5,103	20,844	7,792
GOLDEN STATE WATER COMPANY | Water:
Details of reportable segment
Operating revenues	116,908		90,856	229,620	164,762
GOLDEN STATE WATER COMPANY | Reportable Legal Entities | Water:
Details of reportable segment
Operating revenues	116,908		90,856	229,620	164,762
Operating income (loss)	50,524		27,711	90,763	44,710
Interest expense (income), net	6,515		5,318	12,009	10,463
Net property, plant and equipment	1,666,700		1,553,389	1,666,700	1,553,389
Depreciation and amortization	8,674		8,553	18,280	17,098
Income tax expense	11,934		5,103	20,844	7,792
Capital additions	34,567		35,519	76,572	66,984
BVES | Electric:
Details of reportable segment
Operating revenues	8,828		8,217	21,732	20,109
BVES | Reportable Legal Entities | Electric:
Details of reportable segment
Operating revenues	8,828		8,217	21,732	20,109
Operating income (loss)	2,103		2,038	5,734	5,636
Interest expense (income), net	654		295	1,227	408
Net property, plant and equipment	130,502		111,394	130,502	111,394
Depreciation and amortization	759		686	1,507	1,340
Income tax expense	247		215	948	1,167
Capital additions	4,386		5,306	11,038	8,774
ASUS | Reportable Legal Entities | Contracted services:
Details of reportable segment
Operating revenues	31,664		23,534	67,471	46,306
Operating income (loss)	6,354		4,571	13,650	8,341
Interest expense (income), net	327		(102)	554	(237)
Net property, plant and equipment	16,859		18,704	16,859	18,704
Depreciation and amortization	825		932	1,674	1,847
Income tax expense	1,506		1,108	3,191	2,052
Capital additions	359		557	1,039	794
Golden State Water Company and Bear Valley Electric Service Inc.
Details of reportable segment
Public Utilities Property Plant and Equipment Depreciation on Transportation Equipment	$ 155	$ 212	$ 95	$ 523	$ 189