Revenues - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 122,607	$ 128,414	$ 231,177	$ 245,474
GOLDEN STATE WATER COMPANY
Disaggregation of Revenue [Line Items]
Total operating revenues	90,856	91,633	164,762	166,662
Water: | GOLDEN STATE WATER COMPANY
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, excluding assessed tax	84,980	88,185	158,545	163,524
Total operating revenues	90,856	91,633	164,762	166,662
Electric: | BVESI
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, excluding assessed tax	8,413	8,374	20,992	20,253
Total operating revenues	8,217	8,108	20,109	19,647
Contracted services: | ASUS
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, excluding assessed tax	23,534	28,673	46,306	59,165
Tariff-based revenues | Water: | GOLDEN STATE WATER COMPANY
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, excluding assessed tax	83,612	86,687	156,110	160,975
Tariff-based revenues | Electric: | BVESI
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, excluding assessed tax	8,381	8,330	20,933	20,007
Surcharges (cost-recovery activities) | Water: | GOLDEN STATE WATER COMPANY
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, excluding assessed tax	797	975	1,346	1,509
Surcharges (cost-recovery activities) | Electric: | BVESI
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, excluding assessed tax	32	44	59	246
Other | Water: | GOLDEN STATE WATER COMPANY
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, excluding assessed tax	571	523	1,089	1,040
WRAM under-collection (alternative revenue program) | Water: | GOLDEN STATE WATER COMPANY
Disaggregation of Revenue [Line Items]
Alternative revenue programs, net	5,876	3,448	6,217	3,138
WRAM under-collection (alternative revenue program) | Electric: | BVESI
Disaggregation of Revenue [Line Items]
Alternative revenue programs, net	(196)	(266)	(883)	(606)
Water | Contracted services: | ASUS
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, excluding assessed tax	14,175	18,765	27,721	37,648
Wastewater | Contracted services: | ASUS
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, excluding assessed tax	$ 9,359	$ 9,908	$ 18,585	$ 21,517