Utility Plant and Intangible Assets - By Major Asset Class (Details) - USD ($) $ in Thousands		Dec. 31, 2024	Dec. 31, 2023
Utility plant utilized in continuing operations by major asset class
Total utility plant, at cost		$ 2,442,895	$ 2,279,621
Less — accumulated depreciation		(648,199)	(624,472)
Construction work in progress		304,929	237,131
Net utility plant		2,099,625	1,892,280
Water
Utility plant utilized in continuing operations by major asset class
Total utility plant, at cost		2,271,768	2,123,150
Water | Land
Utility plant utilized in continuing operations by major asset class
Total utility plant, at cost		18,240	18,290
Water | Intangible assets
Utility plant utilized in continuing operations by major asset class
Total utility plant, at cost		31,004	30,917
Water | Source of water supply
Utility plant utilized in continuing operations by major asset class
Total utility plant, at cost		115,247	111,112
Water | Pumping
Utility plant utilized in continuing operations by major asset class
Total utility plant, at cost		253,150	234,264
Water | Water treatment
Utility plant utilized in continuing operations by major asset class
Total utility plant, at cost		114,784	98,533
Water | Transmission and distribution
Utility plant utilized in continuing operations by major asset class
Total utility plant, at cost		1,589,763	1,489,974
Water | Other
Utility plant utilized in continuing operations by major asset class
Total utility plant, at cost		149,580	140,060
Electric: | Intangible assets
Utility plant utilized in continuing operations by major asset class
Total utility plant, at cost		1,200	1,200
GSWC
Utility plant utilized in continuing operations by major asset class
Less — accumulated depreciation		(561,256)	(543,135)
Construction work in progress		245,314	195,742
Net utility plant		1,911,369	1,735,534
GSWC | Water
Utility plant utilized in continuing operations by major asset class
Total utility plant, at cost		2,227,311	2,082,927
GSWC | Water | Land
Utility plant utilized in continuing operations by major asset class
Total utility plant, at cost		18,240	18,290
GSWC | Water | Intangible assets
Utility plant utilized in continuing operations by major asset class
Total utility plant, at cost		31,004	30,917
GSWC | Water | Source of water supply
Utility plant utilized in continuing operations by major asset class
Total utility plant, at cost		115,247	111,112
GSWC | Water | Pumping
Utility plant utilized in continuing operations by major asset class
Total utility plant, at cost		253,150	234,264
GSWC | Water | Water treatment
Utility plant utilized in continuing operations by major asset class
Total utility plant, at cost		114,784	98,533
GSWC | Water | Transmission and distribution
Utility plant utilized in continuing operations by major asset class
Total utility plant, at cost		1,589,763	1,489,974
GSWC | Water | Other
Utility plant utilized in continuing operations by major asset class
Total utility plant, at cost		105,123	99,837
GSWC | Electric:
Utility plant utilized in continuing operations by major asset class
Total utility plant, at cost		0	0
GSWC | Electric: | Transmission and distribution
Utility plant utilized in continuing operations by major asset class
Total utility plant, at cost		0	0
GSWC | Electric: | Generation
Utility plant utilized in continuing operations by major asset class
Total utility plant, at cost		0	0
GSWC | Electric: | Other
Utility plant utilized in continuing operations by major asset class
Total utility plant, at cost	[1]	0	0
BVES | Electric:
Utility plant utilized in continuing operations by major asset class
Total utility plant, at cost		171,127	156,471
BVES | Electric: | Transmission and distribution
Utility plant utilized in continuing operations by major asset class
Total utility plant, at cost		141,634	126,143
BVES | Electric: | Generation
Utility plant utilized in continuing operations by major asset class
Total utility plant, at cost		12,583	12,583
BVES | Electric: | Other
Utility plant utilized in continuing operations by major asset class
Total utility plant, at cost	[1]	$ 16,910	$ 17,745

[1]      Includes intangible assets of $1.2 million for the years ended December 31, 2024 and 2023 for studies performed.