Revenue from Contract with Customers - Additional Information (Details) - Sales	9 Months Ended
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%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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