Commitments Narrative (Details) (USD $) In Thousands, unless otherwise specified	0 Months Ended	12 Months Ended										12 Months Ended				12 Months Ended
	Nov. 14, 2013	Dec. 31, 2013 agreement	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Santa Clara Valley Water District [Member] gal	Dec. 31, 2012 Santa Clara Valley Water District [Member] gal	Dec. 31, 2011 Santa Clara Valley Water District [Member] gal	Dec. 31, 1997 Service Agreements [Member]	Dec. 31, 2013 Service Agreements [Member]	Dec. 31, 2013 Concession Fees [Member]	Dec. 31, 2012 Concession Fees [Member]	Dec. 31, 2013 SJWTX,Inc. dba Canyon Lake Water Supply Corporation [Member] Guadalupe-Blanco River Authority [Member] acre_foot	Dec. 31, 2013 SJW Corp. [Member] employee	Dec. 31, 2013 Executive, Administrative or Supervisory Personnel [Member] SJW Corp. [Member] employee	Dec. 31, 2013 Union Member [Member] SJW Corp. [Member] employee	Dec. 31, 2013 Minimum [Member]	Dec. 31, 2013 Maximum [Member]
Long-term Purchase Commitment [Line Items]
Master contract, negotiated term for delivery schedules					3 years
Water purchased in millions of gallons					22,700,000,000	22,800,000,000	21,900,000,000
Purchased water		$ 63,225	$ 66,106	$ 54,317	$ 52,500	$ 48,800	$ 43,500
Minimum percent of delivery schedule to be purchased in 2013					90.00%
Minimum volume of water to be purchased in 2013					21,000,000,000
Cost of water to be purchased in 2013					50,300
Current contract water rate					2.4
Contrasct life of agreement with City of Cupertino								25 years								5 years	70 years
Concession fee with City of Cupertino		18,341	15,561						10,077	6,800	6,800
Long-term Purchase Commitment, Minimum Area Required, Next Twelve Months												6,700
Notice period required for contract adjustment												60 days
Number of water agreements		180
Water property rights commitments																$ 819	$ 1,300
Number of employees													340	107	233
Collective Bargaining Agreement, Term of Contract	3 years
Collective bargaining agreement percent of wage increase for 2011	2.00%
Collective bargaining agreement percent of wage increase for 2012	2.00%
Collective bargaining agreement percent of wage increase for 2013	3.00%