XML 54 R27.htm IDEA: XBRL DOCUMENT v2.4.0.8

General - Additional Information (Details) (USD $) In Thousands, unless otherwise specified	0 Months Ended	9 Months Ended
	Sep. 29, 2014	Sep. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Water reduction target goal (percent)		20.00%
Authorized Regulatory Surcharge, Gross	$ 46,700
Customer refund for over rate collections, one time refund	$ 200

X

- Definition

Authorized Regulatory Surcharge, Gross

+ References

No definition available.

+ Details

Name:	sjw_AuthorizedRegulatorySurchargeGross
Namespace Prefix:	sjw_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

Customer Refund for Over Rate Collections

+ References

No definition available.

+ Details

Name:	sjw_CustomerRefundforOverRateCollections
Namespace Prefix:	sjw_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Water Reduction Target Goal, Percentage

+ References

No definition available.

+ Details

Name:	sjw_WaterReductionTargetGoalPercentage
Namespace Prefix:	sjw_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration