Utility Plant and Intangible Assets - Schedule of Components (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023
Intangible assets
Total intangible assets		$ 32,431	$ 32,345
Less — accumulated amortization		(28,332)	(27,275)
Intangible assets, net of amortization		4,099	5,070
Intangible assets not subject to amortization	[1]	383	383
Total utility plant, at cost		$ 2,442,895	$ 2,279,621
Conservation programs
Intangible assets
Weighted Average Amortization Period (in years)		3 years	3 years
Total intangible assets		$ 9,486	$ 9,486
Water and water service rights
Intangible assets
Weighted Average Amortization Period (in years)		30 years	30 years
Total intangible assets	[2]	$ 8,695	$ 8,695
Water planning studies
Intangible assets
Weighted Average Amortization Period (in years)		14 years	14 years
Total intangible assets		$ 14,250	$ 14,164
GSWC
Intangible assets
Total intangible assets		30,622	30,536
Less — accumulated amortization		(27,145)	(26,294)
Intangible assets, net of amortization		3,477	4,242
Intangible assets not subject to amortization	[1]	$ 382	$ 382
GSWC | Conservation programs
Intangible assets
Weighted Average Amortization Period (in years)		3 years	3 years
Total intangible assets		$ 9,486	$ 9,486
GSWC | Water and water service rights
Intangible assets
Weighted Average Amortization Period (in years)		30 years	30 years
Total intangible assets	[2]	$ 8,124	$ 8,124
GSWC | Water planning studies
Intangible assets
Weighted Average Amortization Period (in years)		14 years	14 years
Total intangible assets		$ 13,012	$ 12,926
Intangible assets | American States Utility Services
Intangible assets
Total utility plant, at cost		$ 600	$ 600

[1] The intangible assets not subject to amortization primarily consist of organization and consent fees.

[2] Includes intangible assets of $0.6 million for contracted services included in “Other Property and Investments” on the consolidated balance sheets as of December 31, 2024 and 2023.