Long-Term Debt Debt Maturity Schedule (Details) $ in Thousands	12 Months Ended
Dec. 31, 2016 USD ($) payment	Dec. 31, 2015 USD ($)
Debt Instrument [Line Items]
Long-term debt	$ 437,717	$ 384,316
Mortgages [Member]
Debt Instrument [Line Items]
Loan amortization period	10 years
Number of monthly principal and interest payments \| payment	120
Mortgages [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Stated interest rates	5.61%
Mortgages [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Stated interest rates	6.09%
Mortgages [Member] \| 444 West Santa Clara Street, L.P. [Member]
Debt Instrument [Line Items]
Loan amortization period	20 years
Long-term debt	$ 2,717	2,836
Stated interest rates	5.68%
Fiscal Year Amortization Schedule [Abstract]
Total payment, 2016	$ 276
Total payment, 2017	276
Total payment, 2018	276
Total payment, 2019	276
Total payment, 2020	2,208
Interest, 2016	150
Interest, 2017	143
Interest, 2018	135
Interest, 2019	127
Interest, 2020	40
Principal, 2016	126
Principal, 2017	133
Principal, 2018	141
Principal, 2019	149
Principal, 2020	$ 2,168
444 West Santa Clara Street, L.P. [Member]
Debt Instrument [Line Items]
Limited partership interest percentage	70.00%
San Jose Water Company [Member] \| Standby Letters of Credit [Member]
Fiscal Year Amortization Schedule [Abstract]
Line of Credit Facility, Renewal Term	1 year
San Jose Water Company [Member] \| Public Utility, Bonds [Member] \| California Pollution Control Financing Authority Revenue Bonds [Member]
Debt Instrument [Line Items]
Long-term debt	$ 120,000
San Jose Water Company [Member] \| SDWSRF loans [Member]
Debt Instrument [Line Items]
Long-term debt	$ 0	$ 1,849
San Jose Water Company [Member] \| SDWSRF loans [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Stated interest rates	2.39%
San Jose Water Company [Member] \| SDWSRF loans [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Stated interest rates	2.60%

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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