| **Income Taxes (Schedule Of Reasons For Differences Between Statutory Federal Income Tax Rate To Income Before Income Tax Expense) (Details) (USD $)In Thousands, unless otherwise specified** | 12 Months Ended                                                                     |
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| **Income Taxes [Abstract]**                                                                                                                                                                    |                                                                                |   |   |   |   |
| Computed Federal tax expense at statutory rate                                                                                                                                                 | $ 83,686us-gaap_FederalIncomeTaxExpenseBenefitContinuingOperations                  | $ 78,436us-gaap_FederalIncomeTaxExpenseBenefitContinuingOperations | $ 86,470us-gaap_FederalIncomeTaxExpenseBenefitContinuingOperations |   |   |
| Decrease in Federal tax expense related to an income tax accounting change for qualifying utility asset improvement costs                                                                      | (57,015)us-gaap_IncomeTaxReconciliationNondeductibleExpenseOther                    | (57,467)us-gaap_IncomeTaxReconciliationNondeductibleExpenseOther | (28,948)us-gaap_IncomeTaxReconciliationNondeductibleExpenseOther |   |   |
| State income taxes, net of Federal tax benefit                                                                                                                                                 | (640)us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes                        | 1,338us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes | 8,235us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes |   |   |
| Increase in tax expense for depreciation expense to be recovered in future rates                                                                                                               | 317us-gaap_IncomeTaxReconciliationNondeductibleExpenseDepreciation                  | 295us-gaap_IncomeTaxReconciliationNondeductibleExpenseDepreciation | 361us-gaap_IncomeTaxReconciliationNondeductibleExpenseDepreciation |   |   |
| Stock-based compensation                                                                                                                                                                       | (168)us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense | (421)us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense | (386)us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense |   |   |
| Deduction for Aqua America common dividends paid under employee benefit plan                                                                                                                   | (350)us-gaap_EmployeeStockOwnershipPlanESOPTaxBenefitOfDividendsPaidToPlan          | (414)us-gaap_EmployeeStockOwnershipPlanESOPTaxBenefitOfDividendsPaidToPlan | (387)us-gaap_EmployeeStockOwnershipPlanESOPTaxBenefitOfDividendsPaidToPlan |   |   |
| Amortization of deferred investment tax credits                                                                                                                                                | (416)us-gaap_IncomeTaxReconciliationTaxCreditsInvestment                            | (420)us-gaap_IncomeTaxReconciliationTaxCreditsInvestment | (420)us-gaap_IncomeTaxReconciliationTaxCreditsInvestment |   |   |
| Other, net                                                                                                                                                                                     | (195)us-gaap_IncomeTaxReconciliationOtherAdjustments                                | (114)us-gaap_IncomeTaxReconciliationOtherAdjustments | 295us-gaap_IncomeTaxReconciliationOtherAdjustments |   |   |
| Actual income tax expense                                                                                                                                                                      | $ 25,219us-gaap_IncomeTaxExpenseBenefit                                             | $ 21,233us-gaap_IncomeTaxExpenseBenefit | $ 65,220us-gaap_IncomeTaxExpenseBenefit | $ 67,590us-gaap_IncomeTaxExpenseBenefit | $ 73,521us-gaap_IncomeTaxExpenseBenefit |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
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| - Definition
The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
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| - Definition
The tax benefit resulting from dividends paid on preferred stock held by an employee stock option plan, when that stock is not a common stock equivalent.
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|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of current and deferred federal income tax expense (benefit) attributable to income (loss) from continuing operations.
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.
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|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to nondeductible depreciation.
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|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to other nondeductible expenses.
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| - Definition
Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to other adjustments.
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| - Definition
Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to state and local income tax expense (benefit).
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to investment tax credit.
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