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Revenue from Contract with Customers - Additional Information (Details) - Sales | 9 Months Ended
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Sep. 30, 2020
GOLDEN STATE WATER COMPANY | Water Service Utility Operations [Member] |
Disaggregation of Revenue [Line Items] |
Concentration Risk, Percentage | 90.00%
Golden State Water Company and Bear Valley Electric Service Inc. | Electric Service Utility Operations |
Disaggregation of Revenue [Line Items] |
Concentration Risk, Percentage | 90.00%

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