Summary of Significant Accounting Policies (Revenue, Balancing and Memorandum Accounts) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue from External Customer [Line Items]
Regulated operating revenue, water surcharge	$ 3,807	$ 4,605	$ 3,872
San Jose Water Company [Member]
Revenue from External Customer [Line Items]
Nonregulated operating revenue	$ 6,451	$ 6,145	$ 6,175

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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