Long-Term Debt Debt Maturity Schedule (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Debt Instrument [Line Items]
Long-term debt	$ 340,990,000	$ 344,686,000
Mortgages [Member]
Debt Instrument [Line Items]
Loan amortization period	25 years
Number of monthly principal and interest payments	120
Fiscal Year Amortization Schedule [Abstract]
Total payment, 2013	6,216,000
Total payment, 2014	1,229,000
Total payment, 2015	1,229,000
Total payment, 2016	4,034,000
Total payment, 2017	11,470,000
Interest, 2013	1,017,000
Interest, 2014	877,000
Interest, 2015	856,000
Interest, 2016	762,000
Interest, 2017	110,000
Principal, 2013	5,199,000
Principal, 2014	352,000
Principal, 2015	373,000
Principal, 2016	3,272,000
Principal, 2017	11,360,000
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	3,153,000	3,248,000
Stated interest rates	5.68%
Fiscal Year Amortization Schedule [Abstract]
Total payment, 2013	276,000
Total payment, 2014	276,000
Total payment, 2015	275,000
Total payment, 2016	276,000
Total payment, 2017	276,000
Total payment, thereafter	3,038,000
Interest, 2013	176,000
Interest, 2014	170,000
Interest, 2015	163,000
Interest, 2016	157,000
Interest, 2017	150,000
Interest, thereafter	448,000
Principal, 2013	100,000
Principal, 2014	106,000
Principal, 2015	112,000
Principal, 2016	119,000
Principal, 2017	126,000
Principal, thereafter	2,590,000
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]
Debt Instrument [Line Items]
Standby letters of credit	3,000,000
Fiscal Year Amortization Schedule [Abstract]
Line of Credit Facility, Renewal Term	1 year
San Jose Water Company [Member] | Bonds [Member] | California Pollution Control Financing Authority Revenue Bonds [Member]
Debt Instrument [Line Items]
Long-term debt	50,000,000	50,000,000
Stated interest rates	5.10%
San Jose Water Company [Member] | SDWSRF loans [Member]
Debt Instrument [Line Items]
Long-term debt	2,281,000	2,464,000
Fiscal Year Amortization Schedule [Abstract]
Total payment, 2013	153,000
Total payment, 2014	196,000
Total payment, 2015	196,000
Total payment, 2016	195,000
Total payment, 2017	196,000
Total payment, thereafter	1,783,000
Interest, 2013	56,000
Interest, 2014	53,000
Interest, 2015	49,000
Interest, 2016	45,000
Interest, 2017	42,000
Interest, thereafter	193,000
Principal, 2013	97,000
Principal, 2014	143,000
Principal, 2015	147,000
Principal, 2016	150,000
Principal, 2017	154,000
Principal, thereafter	$ 1,590,000
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%