Summary of Significant Accounting Policies: (Policies)	6 Months Ended
Summary of Significant Accounting Policies: (Policies)	Jun. 30, 2015
Accounting Policies [Abstract]
Nature of Operations and Basis of Presentation	Nature of Operations: American States Water Company (“AWR”) is the parent company of Golden State Water Company (“GSWC”) and American States Utility Services, Inc. (“ASUS”) (and its subsidiaries, Fort Bliss Water Services Company (“FBWS”), Terrapin Utility Services, Inc. (“TUS”), Old Dominion Utility Services, Inc. (“ODUS”), Palmetto State Utility Services, Inc. (“PSUS”) and Old North Utility Services, Inc. (“ONUS”)). The subsidiaries of ASUS may be collectively referred to herein as the “Military Utility Privatization Subsidiaries.” GSWC is a public utility engaged principally in the purchase, production, distribution and sale of water in California serving approximately 258,000 customers. GSWC also distributes electricity in several San Bernardino County mountain communities in California serving approximately 24,000 customers through its Bear Valley Electric Service (“BVES”) division. Although Registrant has a diversified base of residential, industrial and other customers, revenues derived from commercial and residential water customers accounted for approximately 90% of total water revenues during the three and six months ended June 30, 2015 and 2014. The California Public Utilities Commission (“CPUC”) regulates GSWC’s water and electric businesses, in matters including properties, rates, services, facilities and other matters, and transactions by GSWC with its affiliates. AWR’s assets and operating income are primarily those of GSWC. ASUS, through its wholly owned subsidiaries, operates, maintains and performs construction activities (including renewal and replacement capital work) on water and/or wastewater systems at various United States military bases pursuant to 50-year firm fixed-price contracts. These contracts are subject to periodic price redeterminations and modifications for changes in circumstances, changes in laws and regulations and additions to the contract value for new construction of facilities at the military bases. There is no direct regulatory oversight by the CPUC over AWR or the operations, rates or services provided by ASUS or any of its wholly owned subsidiaries. Basis of Presentation: The consolidated financial statements and notes thereto are being presented in a combined report being filed by two separate Registrants: AWR and GSWC. References in this report to “Registrant” are to AWR and GSWC, collectively, unless otherwise specified. Certain prior period amounts in the consolidated and GSWC Statements of Cash Flow have been reclassified to conform to the 2015 presentation of "Regulatory assets" as a separate line item. The consolidated financial statements of AWR include the accounts of AWR and its subsidiaries, all of which are wholly owned. These financial statements are prepared in conformity with accounting principles generally accepted in the United States of America. Inter-company transactions and balances have been eliminated in the AWR consolidated financial statements. The consolidated financial statements included herein have been prepared by Registrant, without audit, pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). The December 31, 2014 condensed consolidated balance sheet data was derived from audited financial statements, but does not include all disclosures required by generally accepted accounting principles ("GAAP"). The preparation of the consolidated financial statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. In the opinion of management, all adjustments consisting of normal, recurring items and estimates necessary for a fair statement of the results for the interim periods have been made. It is suggested that these consolidated financial statements be read in conjunction with the consolidated financial statements and the notes thereto included in the Form 10-K for the year ended December 31, 2014 filed with the SEC.
GSWC's Related Party Transactions	GSWC's Related Party Transactions: In May 2013, AWR issued an interest bearing promissory note (the "Note") to GSWC for $20.0 million which expires on May 23, 2018. Under the terms of the Note, AWR may borrow from GSWC amounts up to $20.0 million for working capital purposes. AWR agreed to pay any unpaid principal amounts outstanding under the Note, plus accrued interest. As of June 30, 2015, AWR had $3.0 million outstanding and owed to GSWC under this Note. GSWC and ASUS provide and receive various support services to and from their parent, AWR, and among themselves. GSWC also allocates certain corporate office administrative and general costs to its affiliate, ASUS, using allocation factors approved by the CPUC. GSWC allocated corporate office administrative and general costs to ASUS of approximately $609,000 and $677,000 during the three months ended June 30, 2015 and 2014, respectively, and approximately $1,316,000 and $1,373,000 during the six months ended June 30, 2015 and 2014, respectively. In addition, AWR has a $100.0 million syndicated credit facility. AWR borrows under this facility and provides funds to its subsidiaries, including GSWC, in support of their operations. The interest rate charged to GSWC and ASUS is sufficient to cover AWR’s interest cost under the credit facility. Amounts owed to GSWC by its parent, AWR, or for allocated expenses are included in GSWC's inter-company receivables as of June 30, 2015 and December 31, 2014.
Sales and Use Taxes	Sales and Use Taxes: GSWC bills certain sales and use taxes levied by state or local governments to its customers. Included in these sales and use taxes are franchise fees, which GSWC pays to various municipalities (based on ordinances adopted by these municipalities) in order to use public right of way for utility purposes. GSWC bills these franchise fees to its customers based on a CPUC-authorized rate for each rate-making area as applicable. These franchise fees, which are required to be paid regardless of GSWC’s ability to collect from the customer, are accounted for on a gross basis. GSWC’s franchise fees billed to customers and recorded as operating revenue were approximately $996,000 and $975,000 for the three months ended June 30, 2015 and 2014, respectively, and $1.9 million and $1.8 million for the six months ended June 30, 2015 and 2014, respectively. When GSWC acts as an agent, and the tax is not required to be remitted if it is not collected from the customer, the taxes are accounted for on a net basis. Depending on the state in which the operations are conducted, ASUS and its subsidiaries are also subject to certain state non-income tax assessments generally computed on a “gross receipts” or “gross revenues” basis. These non-income tax assessments are required to be paid regardless of whether the subsidiary is reimbursed by the U.S. government for these assessments under its 50-year contracts. The non-income tax assessments are accounted for on a gross basis and totaled $53,000 and $157,000 during the three months ended June 30, 2015 and 2014, respectively, and $86,000 and $306,000 for the six months ended June 30, 2015 and 2014, respectively.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements: In May 2014, the Financial Accounting Standards Board ("FASB") issued updated accounting guidance on revenue recognition. The guidance will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective. Under this guidance, an entity will recognize revenue when it transfers promised goods or services to customers in an amount that reflects what the entity expects in exchange for the goods or services. This guidance also requires more detailed disclosures to enable users of the financial statements to understand the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers. On July 9, 2015, the FASB decided to delay the effective date of the new revenue standard by one year. The guidance is effective for fiscal years, and interim periods within those years, beginning after December 15, 2017, and adoption is not permitted earlier than the original effective date, that is, no earlier than 2017. The guidance allows entities to select one of two methods of adoption, either the full retrospective approach, meaning the guidance would be applied to all periods presented, or modified retrospective approach, meaning the cumulative effect of applying the guidance would be recognized as an adjustment to opening retained earnings at January 1, 2018, along with providing certain additional disclosures. Registrant will adopt this guidance in the fiscal year beginning January 1, 2018. Management has not yet selected a transition method nor has it determined the effect of the standard on the Company's ongoing financial reporting. In April 2015, the FASB issued Accounting Standard Update 2015-03, Simplifying the Presentation of Debt Issuance Costs, which requires debt issuance costs to be presented in the balance sheet as a direct deduction from the carrying value of the associated debt liability, rather than as an asset. The standard does not affect the recognition and measurement of debt issuance costs. This guidance is effective January 1, 2016. As of June 30, 2015, Registrant had $5.0 million in debt issuance costs reflected under "Other Noncurrent Assets." Also in April 2015, the FASB issued Accounting Standard Update 2015-05, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40): Customer's Accounting for Fees Paid in a Cloud Computing Arrangement, ASU 2015-05 requires a customer in a cloud computing arrangement to follow internal-use software guidance if both of the following criteria are met: (a) the customer has the contractual right to take possession of the software at any time during the cloud computing arrangement and (b) it can feasibly run the software on its own hardware. If the customer does not meet both criteria, the cloud computing arrangement is considered a service contract and separate accounting for a license would not be permitted. This guidance is effective beginning January 1, 2016 and is not expected to have a material impact on Registrant's consolidated financial statements.