Subsequent Event	9 Months Ended
Sep. 30, 2019
Subsequent Events [Abstract]
Subsequent Event	Subsequent Event California GRC filing Subsequent to the issuance of the Company's Condensed Consolidated Financial Statements for the three and nine months ended September 30, 2018, Cal Water jointly filed a formal settlement agreement in its 2018 GRC with the Public Advocates Office of the CPUC covering the majority of open matters in the case on October 8, 2019. The largest component of the GRC is Cal Water’s Infrastructure Improvement Plan for 2019-2021. The settlement details investment plans that Cal Water and the Public Advocates Office agree should be made to Cal Water’s water infrastructure to continue providing safe, reliable water service to Cal Water customers and communities. The CPUC will consider, but is not required to adopt, the settlement agreement. If the CPUC approves the settlement agreement, Cal Water would be authorized to include in rates $609.0 million to $628.0 million of new projects throughout the state in 2019 to 2021, along with approximately $200.0 million for completion of additional projects begun in 2018 and prior periods. Included in these figures are $148.0 million of advice letter authorizations, which would not be included in rates until related projects are completed. Cal Water anticipates that if the settlement were adopted, it would plan to make capital investments of approximately $809.0 million to $828.0 million in the 2019-2021 period. The settlement proposes, in part, an average water main replacement rate of 0.76% annually company-wide by 2021, with higher replacement rates in some areas. A final decision on the case is expected in late 2019, with new rates going into effect in January of 2020. Cal Water previously filed a request for interim rates beginning January 1, 2020 in the event a final decision is unexpectedly delayed.

Subsequent Event

9 Months Ended

Sep. 30, 2019

California GRC filing

Subsequent to the issuance of the Company's Condensed Consolidated Financial Statements for the three and nine months ended September 30, 2018, Cal Water jointly filed a formal settlement agreement in its 2018 GRC with the Public Advocates Office of the CPUC covering the majority of open matters in the case on October 8, 2019. The largest component of the GRC is Cal Water’s Infrastructure Improvement Plan for 2019-2021. The settlement details investment plans that Cal Water and the Public Advocates Office agree should be made to Cal Water’s water infrastructure to continue providing safe, reliable water service to Cal Water customers and communities. The CPUC will consider, but is not required to adopt, the settlement agreement. If the CPUC approves the settlement agreement, Cal Water would be authorized to include in rates $609.0 million to $628.0 million of new projects throughout the state in 2019 to 2021, along with approximately $200.0 million for completion of additional projects begun in 2018 and prior periods. Included in these figures are $148.0 million of advice letter authorizations, which would not be included in rates until related projects are completed. Cal Water anticipates that if the settlement were adopted, it would plan to make capital investments of approximately $809.0 million to $828.0 million in the 2019-2021 period. The settlement proposes, in part, an average water main replacement rate of 0.76% annually company-wide by 2021, with higher replacement rates in some areas. A final decision on the case is expected in late 2019, with new rates going into effect in January of 2020. Cal Water previously filed a request for interim rates beginning January 1, 2020 in the event a final decision is unexpectedly delayed.