v3.25.2
Regulatory Matters - Narrative (Details) - USD ($)
 6 Months Ended
Jun. 30, 2025
Dec. 31, 2024
Regulatory matters:    
Net regulatory Assets $ 38,001,000 $ 54,679,000
Receivables from litigation settlement 18,700,000 6,415,000
Golden State Water Company and Bear Valley Electric Service Inc.    
Regulatory matters:    
Net regulatory Assets 38,000,000  
Regulatory asset 144,300,000  
Regulatory liability $ 106,300,000  
Commercial paper, term 90 days  
Regulatory asset not accruing carrying costs $ 32,500,000  
Regulatory liabilities not accruing carrying costs 90,500,000  
Golden State Water Company and Bear Valley Electric Service Inc. | Deferred Income Tax Charge    
Regulatory matters:    
Regulatory liabilities not accruing carrying costs 67,300,000  
Golden State Water Company and Bear Valley Electric Service Inc. | Pension Costs and Other Postretirement Benefit Costs    
Regulatory matters:    
Regulatory liabilities not accruing carrying costs 23,200,000  
GSWC    
Regulatory matters:    
Net regulatory Assets (3,039,000) 18,173,000
Litigation settlement, amount awarded 19,000,000  
Receivables from litigation settlement 14,983,000 3,122,000
GSWC | Legal settlement receivable    
Regulatory matters:    
Receivables from litigation settlement 12,500,000  
GSWC | Deferred Income Tax Charge    
Regulatory matters:    
Net regulatory Assets (63,537,000) (63,682,000)
GSWC | Pension Costs and Other Postretirement Benefit Costs    
Regulatory matters:    
Net regulatory Assets (24,363,000) (25,179,000)
BVES    
Regulatory matters:    
Net regulatory Assets 41,040,000 36,506,000
Flowed-through deferred income taxes, net | Golden State Water Company and Bear Valley Electric Service Inc.    
Regulatory matters:    
Regulatory asset not accruing carrying costs 18,300,000  
Flowed-through deferred income taxes, net | GSWC    
Regulatory matters:    
Net regulatory Assets 16,139,000 12,506,000
Derivative instrument memorandum account (Note 5)    
Regulatory matters:    
Regulatory asset not accruing carrying costs 11,200,000  
Derivative instrument memorandum account (Note 5) | BVES    
Regulatory matters:    
Net regulatory Assets 11,244,000 8,823,000
Other Regulatory assets | Golden State Water Company and Bear Valley Electric Service Inc.    
Regulatory matters:    
Regulatory asset not accruing carrying costs 3,000,000.0  
2025 general rate case memorandum accounts (unbilled revenue) | GSWC    
Regulatory matters:    
Net regulatory Assets $ 3,910,000 0
Amortization period 12 months  
2022/2023 general rate case memorandum accounts (unbilled revenue) | GSWC    
Regulatory matters:    
Net regulatory Assets $ 30,687,000 37,711,000
Amortization period 36 months  
Water revenue adjustment mechanism, net of modified cost balancing account    
Regulatory matters:    
Regulatory asset recovery periods 24 months  
Water revenue adjustment mechanism, net of modified cost balancing account | GSWC    
Regulatory matters:    
Net regulatory Assets $ 18,341,000 29,738,000
Regulatory asset recovery periods 18 months  
Water Revenue Adjustment Mechanism ("WRAM")    
Regulatory matters:    
Deferred revenue, revenue recognized $ 0  
Water Revenue Adjustment Mechanism ("WRAM") | GSWC    
Regulatory matters:    
Net regulatory Assets 18,000,000  
Modified Cost Balancing account ("MCBA") | GSWC    
Regulatory matters:    
Net regulatory Assets 300,000  
2023/2024 General Rate Case Memorandum accounts ( unbilled revenue) | BVES    
Regulatory matters:    
Net regulatory Assets $ 9,574,000 9,777,000
Amortization period 36 months  
Wildfire mitigation and other fire prevention related costs memorandum accounts | BVES    
Regulatory matters:    
Net regulatory Assets $ 13,954,000 $ 14,681,000
Vegetation management and other WMP memorandum accounts | BVES | Minimum    
Regulatory matters:    
Amortization period 24 months  
Vegetation management and other WMP memorandum accounts | BVES | Maximum    
Regulatory matters:    
Amortization period 36 months