Significant Accounting Policies (Policies)	12 Months Ended
Significant Accounting Policies (Policies)	Dec. 31, 2014
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation The accompanying consolidated financial statements include the accounts of AWW and its subsidiaries. Intercompany balances and transactions between subsidiaries have been eliminated. The Company uses the equity method to report its investments in joint ventures in which the Company holds a 50% voting interest and cannot exercise control over the operations and policies of the investments. Under the equity method, the Company records its interests as an investment and its percentage share of earnings as earnings or losses of investee.
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures 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 these estimates. The Company considers benefit plan assumptions; the estimates used in impairment testing of goodwill and other long-lived assets, including regulatory assets; revenue recognition; and accounting for income taxes to be its critical accounting estimates. The Company’s significant accounting estimates that are particularly sensitive to change in the near term are amounts reported for pension and other postemployment benefits, contingency-related obligations and goodwill.
Regulation	Regulation The Company’s regulated utilities are subject to economic regulation by the public utility commissions and the local governments of the states in which they operate (the “PUCs”). These PUCs have allowed recovery of costs and credits which the Company has recorded as regulatory assets and liabilities. Accounting for future recovery of costs and credits as regulatory assets and liabilities is in accordance with authoritative guidance applicable to those companies whose rates are established by or are subject to approval by an independent third-party PUC. Regulated utilities defer costs and credits on the balance sheet as regulatory assets and liabilities when it is probable that those costs and credits will be recognized in the rate making process in a period different from the period in which they would have been reflected in operations by a market-based company. These deferred regulatory assets and liabilities are then reflected in the statement of operations in the period in which the costs and credits are reflected in the rates charged for service. (See Note 6)
Property, Plant and Equipment	Property, Plant and Equipment Property, plant and equipment consist primarily of utility plant. Additions to utility plant and replacements of retirement units of property are capitalized. Costs include material, direct labor and such indirect items as engineering and supervision, payroll taxes and benefits, transportation and an allowance for funds used during construction. The cost of repairs; maintenance, including planned major maintenance activities; and minor replacements is charged to maintenance expense as incurred. The costs incurred to acquire and internally develop computer software for internal use are capitalized as a unit of property. The carrying value of these costs amounted to $319,517 and $303,798 at December 31, 2014 and 2013, respectively. When units of property are replaced, retired or abandoned, the recorded value thereof is credited to the asset account and charged to accumulated depreciation. To the extent the Company recovers cost of removal or other retirement costs through rates after the retirement costs are incurred, a regulatory asset is recorded. In some cases, the Company recovers retirement costs through rates during the life of the associated asset and before the costs are incurred. These amounts result in a regulatory liability being reported based on the amounts previously recovered through customer rates, until the costs to retire those assets are incurred. The cost of property, plant and equipment is depreciated using the straight-line average remaining life method. Nonutility property consists primarily of buildings and equipment utilized by the Company for internal operations. This property is stated at cost, net of accumulated depreciation calculated using the straight-line method over the estimated useful lives of the assets, ranging from three to 50 years.
Cash and Cash Equivalents	Cash and Cash Equivalents Substantially all cash is invested in interest-bearing accounts. All highly liquid investments with a maturity of three months or less when purchased are considered to be cash equivalents.
Restricted Funds	Restricted Funds Restricted funds primarily represent proceeds from financings for the construction and capital improvement of facilities and deposits for future services under operation and maintenance projects. The proceeds of these financings are held in escrow until the designated expenditures are incurred. Classification of restricted funds in the balance sheet as either current or long-term is based upon the intended use of the funds.
Accounts Receivable	Accounts and Unbilled Receivables Accounts receivable include regulated utility customer accounts receivable, which represent amounts billed to water and wastewater customers on a cycle basis. Credit is extended based on the guidelines of the applicable PUCs and collateral is generally not required. Also included are market-based trade accounts receivable and nonutility customer receivables of the regulated subsidiaries. Unbilled receivables are accrued when service has been provided but has not been billed to customers.
Allowance for Uncollectible Accounts	Allowance for Uncollectible Accounts Allowances for uncollectible accounts are maintained for estimated probable losses resulting from the Company’s inability to collect receivables from customers. Accounts that are outstanding longer than the payment terms are considered past due. A number of factors are considered in determining the allowance for uncollectible accounts, including the length of time receivables are past due and previous loss history. The Company writes off accounts when they become uncollectible. (See Note 5)
Materials and Supplies	Materials and Supplies Materials and supplies are stated at the lower of cost or net realizable value. Cost is determined using the average cost method. A provision is made to reduce excess or obsolete inventory to its net realizable value.
Goodwill	Goodwill Goodwill is primarily associated with the acquisitions of AWW in 2003 and E’town Corporation in 2001 (the “Acquisitions”) and has been assigned to reporting units based on the fair values at the date of the Acquisitions. The reporting units in the Regulated Businesses segment are aggregated into a single reporting unit. The Market-Based Operations segment is comprised of three reporting units. Goodwill is tested annually or more frequently if changes in circumstances indicate goodwill may be impaired. Impairment exists when the carrying value of a reporting unit exceeds its fair value. Annual impairment tests are performed in the fourth quarter of the calendar year, in conjunction with the timing of the completion of the Company’s annual strategic business plan. The Company considers the carrying value of goodwill to be one of its critical accounting estimates. The Company believes the assumptions and other considerations used to value goodwill to be appropriate. However, if experience differs from the assumptions and considerations used in its analysis, the resulting change could have a material adverse impact on the consolidated financial statements.
Long-Lived Assets	Long-Lived Assets Long-lived assets include land, buildings, equipment and long-term investments. Long-lived assets, other than investments and land, are depreciated over their estimated useful lives, and are reviewed for impairment whenever changes in circumstances indicate the carrying value of the asset may not be recoverable. Such circumstances would include items such as a significant decrease in the market value of a long-lived asset, a significant adverse change in the manner the asset is being used or planned to be used or in its physical condition, or a history of operating or cash flow losses associated with the use of the asset. In addition, changes in the expected useful life of these long-lived assets may also be an impairment indicator. When such events or changes occur, the Company estimates the fair value of the asset from future cash flows expected to result from the use and, if applicable, the eventual disposition of the asset and compares that to the carrying value of the asset. If the carrying value is greater than the fair value, an impairment loss is recorded. The Company considers the estimates used in the determination of fair value of long-lived assets to be one of its critical accounting estimates. The Company believes the assumptions and other considerations used to evaluate the carrying value of long-lived assets are appropriate. However, if actual experience differs from the assumptions and considerations used in its estimates, the resulting change could have a material adverse impact on the consolidated financial statements. The key variables to determine fair value include assumptions regarding sales volume, rates, operating costs, labor and other benefit costs, capital additions, assumed discount rates and other economic factors. These variables require significant management judgment and include inherent uncertainties, since they are forecasting future events. If such assets are considered impaired, an impairment loss is recognized equal to the amount by which the asset’s carrying value exceeds its fair value. The long-lived assets of the regulated utility subsidiaries are tested on a separate entity basis for impairment testing as they are integrated state-wide operations that do not have the option to curtail service and generally have uniform tariffs. A regulatory asset is charged to earnings if and when future recovery in rates of that asset is no longer probable. The Company holds other investments including investments in privately held companies and investments in joint ventures accounted for using the equity method. The Company’s investments in privately held companies and joint ventures are classified as other long-term assets. The fair values of long-term investments are dependent on the financial performance and solvency of the entities in which the Company invests, as well as volatility inherent in the external markets. If such assets are considered impaired, an impairment loss is recognized equal to the amount by which the asset’s carrying value exceeds its fair value.
Advances for Construction and Contributions in Aid of Construction	Advances for Construction and Contributions in Aid of Construction Regulated utility subsidiaries may receive advances for construction (“advances”) and contributions in aid of construction (“contributions”) from customers, home builders and real estate developers to fund construction necessary to extend service to new areas. Advances are refundable for limited periods of time as new customers begin to receive service or other contractual obligations are fulfilled. Included in other current liabilities at December 31, 2014 and 2013 in the accompanying Consolidated Balance Sheets are estimated refunds of $18,366 and $17,308, respectively. Those amounts represent expected refunds during the next 12-month period. Advances that are no longer refundable are reclassified to contributions. Contributions are permanent collections of plant assets or cash for a particular construction project. For ratemaking purposes, the amount of such contributions generally serves as a rate base reduction since the contributions represent non-investor supplied funds. Generally, the Company depreciates utility plant funded by contributions and amortizes its contributions balance as a reduction to depreciation expense, producing a result which is functionally equivalent to reducing the original cost of the utility plant for the contributions. In accordance with applicable regulatory guidelines, some of the Company’s subsidiaries do not amortize contributions, and any contribution received remains on the balance sheet indefinitely. Amortization of contributions in aid of construction was $23,913, $22,363 and $20,979 for the years ended December 31, 2014, 2013 and 2012, respectively.
Recognition of Revenues	Recognition of Revenues Revenues of the regulated utility subsidiaries are recognized as water and wastewater services are provided, and include amounts billed to customers on a cycle basis and unbilled amounts based on estimated usage from the date of the meter reading associated with the latest customer invoice to the end of the accounting period. The Company has agreements with the United States Government to operate and maintain water and wastewater systems at various military bases pursuant to 50-year contracts (“military agreements”). These contracts also include construction components that are accounted for separately from the operations and management components. The military agreements are subject to periodic price redetermination adjustments and modifications for changes in circumstance. Additionally, the Company has agreements ranging in length from two to 40 years with various industries and municipalities to operate and maintain water and wastewater systems (“O&M agreements”). Revenues from operations and management services are recognized as services are provided. (See Note 14)
Construction Contracts	Construction Contracts Revenues from construction projects are recognized over the contract term based on the costs incurred to date during the period compared to the total estimated costs over the entire contract. Losses on contracts are recognized during the period in which the loss first becomes probable and estimable. Revenues recognized during the period in excess of billings on construction contracts are recorded as unbilled revenue. Billings in excess of revenues recognized on construction contracts are recorded as other current liabilities until the recognition criteria are met. Changes in contract performance and related estimated contract profitability may result in revisions to costs and revenues and are recognized in the period in which revisions are determined.
Income Taxes	Income Taxes AWW and its subsidiaries participate in a consolidated federal income tax return for U.S. tax purposes. Members of the consolidated group are charged with the amount of federal income tax expense determined as if they filed separate returns. Certain income and expense items are accounted for in different time periods for financial reporting than for income tax reporting purposes. The Company provides deferred income taxes on the difference between the tax basis of assets and liabilities and the amounts at which they are carried in the financial statements. These deferred income taxes are based on the enacted tax rates expected to be in effect when these temporary differences are projected to reverse. In addition, the regulated utility subsidiaries recognize regulatory assets and liabilities for the effect on revenues expected to be realized as the tax effects of temporary differences, previously flowed through to customers, reverse. Investment tax credits have been deferred by the regulated utility subsidiaries and are being amortized to income over the average estimated service lives of the related assets. The Company recognizes accrued interest and penalties related to tax positions as a component of income tax expense and accounts for sales tax collected from customers and remitted to taxing authorities on a net basis.
Allowance for Funds Used During Construction ("AFUDC")	Allowance for Funds Used During Construction (“AFUDC”) AFUDC is a non-cash credit to income with a corresponding charge to utility plant that represents the cost of borrowed funds or a return on equity funds devoted to plant under construction. The regulated utility subsidiaries record AFUDC to the extent permitted by the PUCs.
Environmental Costs	Environmental Costs The Company’s water and wastewater operations are subject to federal, state, local and foreign requirements relating to environmental protection, and as such, the Company periodically becomes subject to environmental claims in the normal course of business. Environmental expenditures that relate to current operations or provide a future benefit are expensed or capitalized as appropriate. Remediation costs that relate to an existing condition caused by past operations are accrued, on an undiscounted basis, when it is probable that these costs will be incurred and can be reasonably estimated. Remediation costs accrued amounted to $2,200 and $3,300 at December 31, 2014 and 2013, respectively. The accrual relates entirely to a conservation agreement entered into by a subsidiary of the Company with the National Oceanic and Atmospheric Administration (“NOAA”) requiring the Company to, among other provisions, implement certain measures to protect the steelhead trout and its habitat in the Carmel River watershed in the state of California. The Company has agreed to pay $1,100 annually from 2010 to 2016. The Company pursues recovery of incurred costs through all appropriate means, including regulatory recovery through customer rates. The Company’s regulatory assets at December 31, 2014 and 2013 include $7,791 and $8,027, respectively, related to the NOAA agreement.
Derivative Financial Instruments	Derivative Financial Instruments The Company uses derivative financial instruments for purposes of hedging exposures to fluctuations in interest rates. These derivative contracts are entered into for periods consistent with the related underlying exposures and do not constitute positions independent of those exposures. The Company does not enter into derivative contracts for speculative purposes and does not use leveraged instruments. All derivatives are recognized on the balance sheet at fair value. On the date the derivative contract is entered into, the Company may designate the derivative as a hedge of the fair value of a recognized asset or liability (fair-value hedge) or a hedge of a forecasted transaction or of the variability of cash flows to be received or paid related to a recognized asset or liability (cash-flow hedge). Changes in the fair value of a fair-value hedge, along with the gain or loss on the underlying hedged item, are recorded in current-period earnings. The effective portion of gains and losses on cash-flow hedges are recorded in other comprehensive income, until earnings are affected by the variability of cash flows. Any ineffective portion of designated hedges is recognized in current-period earnings. Cash flows from derivative contracts are included in net cash provided by operating activities.
New Accounting Standards	New Accounting Standards The following recently issued accounting standards have been adopted by the Company and have been included in the consolidated results of operations, financial position or footnotes of the accompanying Consolidated Financial Statements: Obligations Resulting from Joint and Several Liability Arrangements In February 2013, the Financial Accounting Standards Board (“FASB”) issued guidance for the recognition, measurement and disclosure of obligations resulting from joint and several liability arrangements for which the total amount of the obligation is fixed at the reporting date. Examples of obligations within the scope of the updated guidance include debt arrangements, other contractual obligations and settled litigation and judicial rulings. The update requires an entity to measure obligations resulting from joint and several liability arrangements for which the total amount of the obligation is fixed at the reporting date as the sum of the following: (a) the amount the reporting entity agreed to pay on the basis of its arrangement among its co-obligors and (b) any additional amount the reporting entity expects to pay on behalf of its co-obligors. The updated guidance also includes additional disclosures regarding the nature and amount of the obligation, as well as other information about those obligations. The update was effective on a retrospective basis for interim and annual periods beginning after December 15, 2013, which for the Company was January 1, 2014. The adoption of this updated guidance did not have an impact on the Company’s results of operations, financial position or cash flows. Foreign Currency Matters In June 2013, the FASB issued guidance for a parent’s accounting for the cumulative translation adjustment upon derecognition of certain subsidiaries or groups of assets within a foreign entity or of an investment in a foreign entity. The amendments resolve differing views in practice and apply to the release of the cumulative translation adjustment into net income when a parent either sells a part or all of its investment in a foreign entity or no longer holds a controlling financial interest in a subsidiary or a business within a foreign entity. The update was effective prospectively for interim and annual periods beginning after December 15, 2013, which for the Company was January 1, 2014. The adoption of this updated guidance did not have an impact on the Company’s results of operations, financial position or cash flows. The following recently issued accounting standards are not yet required to be adopted by the Company: Service Concession Arrangements In January 2014, the FASB issued guidance for an operating entity that enters into a service concession arrangement with a public sector grantor who controls or has the ability to modify or approve the services that the operating entity must provide with the infrastructure, to whom it must provide the services and at what price. The grantor also controls, through ownership or otherwise, any residual interest in the infrastructure at the end of the term of the arrangement. The guidance specifies that an operating entity should not account for the service concession arrangement as a lease. The operating entity should refer instead to other accounting guidance to account for the various aspects of the arrangement. The guidance also specifies that the infrastructure used in the arrangement should not be recognized as property, plant and equipment of the operating entity. This update should be applied on a modified retrospective basis to service concession arrangements that exist at the beginning of an entity’s fiscal year of adoption. This requires the cumulative effect of applying the update to be recognized as an adjustment to the opening retained earnings balance for the annual period of adoption. The update is effective for interim and annual periods beginning after December 15, 2014, which for the Company is January 1, 2015. The adoption of this updated guidance resulted in a decrease to nonutility property and opening retained earnings of approximately $12,000 on January 1, 2015. Reporting Discontinued Operations In April 2014, the FASB issued guidance that changes the criteria for determining which disposals can be presented as discontinued operations and modifies related disclosure requirements. Under the updated guidance, a discontinued operation is defined as a component or group of components that is disposed of or is classified as held for sale and represents a strategic shift that has or will have a major effect on an entity’s operations and financial results. A strategic shift could include a disposal of a major geographical area of operations, a major line of business, a major equity method investment or other major part of the entity. A component comprises operations and cash flows that can be clearly distinguished, operationally and for financial reporting purposes, from the rest of the entity including a reportable segment, an operating segment, a reporting unit, a subsidiary or an asset group. The update no longer precludes presentation as a discontinued operation if there are operations and cash flows of the component that have not been eliminated from the reporting entity’s ongoing operations or if there is significant continuing involvement with a component after its disposal. The updated guidance is effective on a prospective basis for interim and annual periods on or after December 15, 2014, which for the Company is January 1, 2015. In general, this guidance is likely to result in fewer disposals of assets qualifying as discontinued operations, but will ultimately be based on the Company’s future disposal activity. Revenue from Contracts with Customers In May 2014, the FASB issued a comprehensive new revenue recognition standard that supersedes most current revenue recognition guidance, including industry-specific guidance. The core principle of the new guidance is that a company will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. The guidance is effective for annual and interim periods beginning December 15, 2016, which for the Company is January 1, 2017. Early adoption is not permitted. The new guidance allows for either full retrospective adoption, meaning the guidance is applied to all of the periods presented, or modified retrospective adoption, meaning the standard is applied only to the most current period presented in the financial statements. The Company is evaluating the new guidance, the best transition method and the impact the new standard will have on its results of operations, financial position or cash flows. Accounting for Stock-based Compensation with Performance Targets In June 2014, the FASB issued guidance for the accounting for stock-based compensation tied to performance targets. The amendments clarify that a performance target that affects vesting of a share-based payment and that could be achieved after the requisite service period is a performance condition. As a result, the target is not reflected in the estimation of the award’s grant date fair value and compensation cost would be recognized over the required service period, if it is probable that the performance condition will be achieved. The updated guidance may be applied either: (a) prospectively to all awards granted or modified after the effective date or (b) retrospectively to all awards with performance targets that are outstanding as of the beginning of the earliest annual period presented in the financial statements and to all new or modified awards thereafter. The updated guidance is effective for annual periods and interim periods within those annual periods beginning after December 15, 2015, which for the Company is January 1, 2016. Early adoption is permitted. The Company is evaluating the impact the updated guidance will have on its results of operations, financial position or cash flows. Disclosures of Uncertainties about an Entity’s Ability to Continue as a Going Concern In August 2014, the FASB issued guidance that explicitly requires an entity’s management to assess the entity’s ability to continue as a going concern. The new guidance requires an entity to evaluate, at each interim and annual period, whether there are conditions or events that raise substantial doubt about the entity’s ability to continue as a going concern within one year after the date the financial statements are issued (or are available to be issued) and to provide related disclosures, if applicable. The new guidance is effective for annual periods ending after December 15, 2016 and for interim and annual periods thereafter, which for the Company is January 1, 2017. Early adoption is permitted. The adoption of this updated guidance is not expected to have a material impact on results of operations, financial position or cash flows. Hybrid Financial Instruments Issued in the Form of a Share In November 2014, the FASB updated the derivatives and hedging guidance requiring issuers of, or investors in, hybrid financial instruments to determine whether the nature of the host contract is more akin to a debt instrument or an equity instrument by considering the economic characteristics and risks of the entire hybrid financial instrument, including the embedded derivative feature that is being evaluated for separate accounting from the host contract. This update should be applied on a modified retrospective basis to hybrid financial instruments issued in the form of a share that exist at the beginning of an entity’s fiscal year of adoption. The updated guidance is effective for annual periods and interim periods within those annual periods beginning after December 15, 2015, which for the Company is January 1, 2016. Early adoption is permitted. The Company is evaluating the impact the updated guidance will have on its results of operations, financial position or cash flows. Extraordinary and Unusual Items In January 2015, the FASB issued guidance that eliminates the concept of an extraordinary item. As a result, an entity will no longer segregate an extraordinary item and present it separately from the results of ordinary operations or separately disclose income taxes or earnings per share information applicable to an extraordinary item. The presentation and disclosure guidance for items that are unusual in nature or occur infrequently has been retained and expanded to include items that are both unusual in nature and infrequently occurring. The updated guidance is effective for annual periods and interim periods within those annual periods beginning after December 15, 2015, which for the Company is January 1, 2016. Early adoption is permitted. The updated guidance may be applied prospectively or retrospectively to all periods presented in the financial statements. The adoption of this updated guidance is not expected to have a material impact on results of operations, financial position or cash flows. Reclassifications In 2014 the Company reclassified previously reported data to conform to the current presentation for discontinued operations. See Note 3 for additional details on the Company’s discontinued operations. In 2014 the Company revised its 2013 balance sheet to properly reclassify $17,722 of deferred income taxes from current liabilities to current assets. This reclassification was not material to the previously issued financial statements.