General	3 Months Ended
Mar. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
GENERAL	General In the opinion of management, the accompanying unaudited condensed consolidated financial statements reflect all adjustments (consisting only of normal, recurring adjustments) necessary for a fair presentation of the results for the interim periods. The unaudited interim financial information has been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and in accordance with the instructions for Form 10-Q and Rule 10-01 of Regulation S-X promulgated by the Securities and Exchange Commission (the “SEC”). The Notes to Consolidated Financial Statements in SJW Corp.'s 2015 Annual Report on Form 10-K should be read with the accompanying unaudited condensed consolidated financial statements. In February 2015, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2015-02, “Consolidation” which modifies the evaluation of whether limited partnerships and similar legal entities are variable or voting interest entities, eliminates the presumption that the general partner should consolidate a limited partnership, modifies the consolidation analysis for reporting entities that are involved in variable interest entities, particularly those that have fee arrangements and related party relationships, and provides a scope exception from consolidation guidance for reporting entities with interests in legal entities that operate as registered money market funds. ASU 2015-02 was effective for SJW Corp. in the first quarter of 2016. The adoption of ASU 2015-02 did not have a material impact on our consolidated financial statements. Water sales are seasonal in nature and influenced by weather conditions. The timing of precipitation and climatic conditions can cause seasonal water consumption by customers to vary significantly. Due to the seasonal nature of the water business, the operating results for interim periods are not indicative of the operating results for a 12-month period. Revenue is generally higher in the warm, dry summer months when water usage and sales are greater, and lower in the winter months when cooler temperatures and increased rainfall curtail water usage and sales. In response to the ongoing drought in California, on March 17, 2015, the State Water Resources Control Board (“State Water Board”) adopted an expanded emergency conservation regulation that became effective on March 27, 2015. The regulation prohibits certain outdoor water uses for all Californians and also places water usage restrictions on businesses in the restaurant and hospitality sectors. On March 25, 2015, the Santa Clara Valley Water District (“SCVWD”) increased their conservation target from 20% to 30% through the end of 2015. On April 1, 2015, Governor Edmund G. Brown Jr. issued an executive order imposing restrictions to achieve a statewide 25% reduction in potable urban water usage through February 28, 2016 based on 2013 usage. On November 13, 2015, Governor Brown issued Executive Order B-36-15 that calls for an extension of restrictions on urban potable water usage until October 31, 2016, should drought conditions persist through January of 2016. On February 2, 2016, the State Water Board approved a resolution to extend the existing emergency conservation regulation as directed in the November 2015 executive order. On April 9, 2015, the California Public Utilities Commission (“CPUC”) issued a resolution ordering its regulated water utilities to comply with the State Water Board's emergency conservation regulation, conduct additional customer outreach and implement restrictions on outdoor water use. Effective June 15, 2015, San Jose Water Company was authorized by the CPUC to activate Stage 3 of Tariff Rule 14.1 which is a water shortage contingency plan with mandatory water usage reductions and drought surcharges. Tariff Rule 14.1 focuses primarily on restrictions of outdoor water use which accounts for 50% of a typical customer's water usage. The drought surcharges are not recorded in revenue. Rather, they are recorded in a regulatory liability account which has been authorized by the CPUC to track lost revenues from conservation. As of March 31, 2016, San Jose Water Company had accumulated a balance of approximately $512 in the drought surcharge account. This amount will be used to offset future rate increases that would otherwise be necessary to recover lost revenue due to drought conservation efforts as described below. San Jose Water Company is continually working to remain in compliance with the various drought rules and regulations and is also working with local governments as well as the SCVWD to communicate consistent messages to the public about use restrictions and related matters because of the ongoing drought. Effective March 31, 2014, San Jose Water Company received approval from the CPUC to institute a Mandatory Conservation Revenue Adjustment Memorandum Account (“MCRAMA”), using a Water Revenue Adjustment Mechanism (“WRAM”). The account was subsequently renamed the Water Conservation Memorandum Account (“WCMA”). The WCMA calculation methodology allows San Jose Water Company to track lost revenue associated with reduced sales due to the ongoing drought and the associated calls for water use reduction from the SCVWD. San Jose Water Company records the lost revenue captured in the WCMA regulatory accounts once the revenue recognition requirements of FASB ASU Topic 980 - “Regulated Operations,” subtopic 605-25 are met. For further discussion, please see Note 8 and Note 9. Basic earnings per share is calculated using income available to common shareholders, divided by the weighted average number of shares outstanding during the period. Diluted earnings per share is calculated using income available to common shareholders divided by the weighted average number of shares of common stock including both shares outstanding and shares potentially issuable in connection with deferred restricted common stock awards under SJW Corp.'s Long-Term Incentive Plan (as amended, the “Incentive Plan”) and shares potentially issuable under the 2014 Employee Stock Purchase Plan (“ESPP”). For the three months ended March 31, 2016 and 2015, 1,617 and 118 anti-dilutive restricted common stock units were excluded from the dilutive earnings per share calculation, respectively. A portion of depreciation expense is allocated to administrative and general expense. For the three months ended March 31, 2016 and 2015, the amounts allocated to administrative and general expense were $414 and $399, respectively.

General

In the opinion of management, the accompanying unaudited condensed consolidated financial statements reflect all adjustments (consisting only of normal, recurring adjustments) necessary for a fair presentation of the results for the interim periods.

The unaudited interim financial information has been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and in accordance with the instructions for Form 10-Q and Rule 10-01 of Regulation S-X promulgated by the Securities and Exchange Commission (the “SEC”). The Notes to Consolidated Financial Statements in SJW Corp.'s 2015 Annual Report on Form 10-K should be read with the accompanying unaudited condensed consolidated financial statements.

In February 2015, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2015-02, “Consolidation” which modifies the evaluation of whether limited partnerships and similar legal entities are variable or voting interest entities, eliminates the presumption that the general partner should consolidate a limited partnership, modifies the consolidation analysis for reporting entities that are involved in variable interest entities, particularly those that have fee arrangements and related party relationships, and provides a scope exception from consolidation guidance for reporting entities with interests in legal entities that operate as registered money market funds. ASU 2015-02 was effective for SJW Corp. in the first quarter of 2016. The adoption of ASU 2015-02 did not have a material impact on our consolidated financial statements.

Water sales are seasonal in nature and influenced by weather conditions. The timing of precipitation and climatic conditions can cause seasonal water consumption by customers to vary significantly. Due to the seasonal nature of the water business, the operating results for interim periods are not indicative of the operating results for a 12-month period. Revenue is generally higher in the warm, dry summer months when water usage and sales are greater, and lower in the winter months when cooler temperatures and increased rainfall curtail water usage and sales.

In response to the ongoing drought in California, on March 17, 2015, the State Water Resources Control Board (“State Water Board”) adopted an expanded emergency conservation regulation that became effective on March 27, 2015. The regulation prohibits certain outdoor water uses for all Californians and also places water usage restrictions on businesses in the restaurant and hospitality sectors. On March 25, 2015, the Santa Clara Valley Water District (“SCVWD”) increased their conservation target from 20% to 30% through the end of 2015. On April 1, 2015, Governor Edmund G. Brown Jr. issued an executive order imposing restrictions to achieve a statewide 25% reduction in potable urban water usage through February 28, 2016 based on 2013 usage. On November 13, 2015, Governor Brown issued Executive Order B-36-15 that calls for an extension of restrictions on urban potable water usage until October 31, 2016, should drought conditions persist through January of 2016. On February 2, 2016, the State Water Board approved a resolution to extend the existing emergency conservation regulation as directed in the November 2015 executive order.

On April 9, 2015, the California Public Utilities Commission (“CPUC”) issued a resolution ordering its regulated water utilities to comply with the State Water Board's emergency conservation regulation, conduct additional customer outreach and implement restrictions on outdoor water use. Effective June 15, 2015, San Jose Water Company was authorized by the CPUC to activate Stage 3 of Tariff Rule 14.1 which is a water shortage contingency plan with mandatory water usage reductions and drought surcharges. Tariff Rule 14.1 focuses primarily on restrictions of outdoor water use which accounts for 50% of a typical customer's water usage. The drought surcharges are not recorded in revenue. Rather, they are recorded in a regulatory liability account which has been authorized by the CPUC to track lost revenues from conservation. As of March 31, 2016, San Jose Water Company had accumulated a balance of approximately $512 in the drought surcharge account. This amount will be used to offset future rate increases that would otherwise be necessary to recover lost revenue due to drought conservation efforts as described below. San Jose Water Company is continually working to remain in compliance with the various drought rules and regulations and is also working with local governments as well as the SCVWD to communicate consistent messages to the public about use restrictions and related matters because of the ongoing drought.

Effective March 31, 2014, San Jose Water Company received approval from the CPUC to institute a Mandatory Conservation Revenue Adjustment Memorandum Account (“MCRAMA”), using a Water Revenue Adjustment Mechanism (“WRAM”). The account was subsequently renamed the Water Conservation Memorandum Account (“WCMA”). The WCMA calculation methodology allows San Jose Water Company to track lost revenue associated with reduced sales due to the ongoing drought and the associated calls for water use reduction from the SCVWD. San Jose Water Company records the lost revenue captured in the WCMA regulatory accounts once the revenue recognition requirements of FASB ASU Topic 980 - “Regulated Operations,” subtopic 605-25 are met. For further discussion, please see Note 8 and Note 9.

Basic earnings per share is calculated using income available to common shareholders, divided by the weighted average number of shares outstanding during the period. Diluted earnings per share is calculated using income available to common shareholders divided by the weighted average number of shares of common stock including both shares outstanding and shares potentially issuable in connection with deferred restricted common stock awards under SJW Corp.'s Long-Term Incentive Plan (as amended, the “Incentive Plan”) and shares potentially issuable under the 2014 Employee Stock Purchase Plan (“ESPP”). For the three months ended March 31, 2016 and 2015, 1,617 and 118 anti-dilutive restricted common stock units were excluded from the dilutive earnings per share calculation, respectively.

A portion of depreciation expense is allocated to administrative and general expense. For the three months ended March 31, 2016 and 2015, the amounts allocated to administrative and general expense were $414 and $399, respectively.