| **Commitments And Contingencies (Narrative) (Details) (USD $)In Thousands, unless otherwise specified** | 1 Months Ended                                                    | 12 Months Ended                            |
|---------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------|--------------------------------------------|
||
| **Commitments And Contingencies [Line Items]**                                                          |                                                              |                                       |   |   |
| Operating lease adjustment period                                                                       |                                                              |                                       | 5 years |   |
| Annual lease payments for land                                                                          |                                                              |                                       | $ 557us-gaap_OperatingLeasesRentExpenseMinimumRentals |   |
| Annual lease payments for land due on aggregate remaining years                                         |                                                              |                                       | 13,189wtr_AnnualLeasePaymentsForLandDueOnAggregateRemainingYears |   |
| Estimated annual commitments to purchase water through the next five years                              |                                                              |                                       | 9,281wtr_EstimatedAnnualCommitmentsToPurchaseWaterThroughNextFiveYears |   |
| Aggregate amount of the commitments for the remaining years                                             |                                                              |                                       | 23,458wtr_LongTermPurchaseAggregateCommitmentRemainingYears |   |
| Purchase Obligation Term                                                                                |                                                              |                                       | 20 years |   |
| capital investment in water mains                                                                       | 100wtr_CapitalInvestmentInWaterMains                              |                                       |   |   |
| Payment to support and promote conservation education and awareness                                     | 12wtr_PaymentToSupportAndPromoteConservationEducationAndAwareness |                                       |   |   |
| Estimated capital expenditures required next four years                                                 |                                                              |                                       | 4,200wtr_EstimatedCapitalExpendituresRequiredNextFourYears |   |
| Aggregate amount accrued for loss contingencies                                                         |                                                              |                                       | 11,885us-gaap_LossContingencyEstimateOfPossibleLoss |   |
| Amount probable of recovery through insurance                                                           |                                                              |                                       | 1,210us-gaap_EstimatedInsuranceRecoveries |   |
| Potential fines                                                                                         | 0wtr_PotenntialFinesForAllegedViolations                          | 227wtr_PotenntialFinesForAllegedViolations |   |   |
| Contingent liability for self-insured employee medical benefit program                                  |                                                              |                                       | $ 1,468wtr_ContingentLiabilityForSelfInsuredEmployeeMedicalBenefitProgram | $ 1,965wtr_ContingentLiabilityForSelfInsuredEmployeeMedicalBenefitProgram |
| Minimum [Member]                                                                                        |                                                              |                                       |   |   |
| **Commitments And Contingencies [Line Items]**                                                          |                                                              |                                       |   |   |
| Operating leases, expiration year                                                                       |                                                              |                                       | 2015 |   |
| Maximum [Member]                                                                                        |                                                              |                                       |   |   |
| **Commitments And Contingencies [Line Items]**                                                          |                                                              |                                       |   |   |
| Operating leases, expiration year                                                                       |                                                              |                                       | 2051 |   |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Carrying amount as of the balance sheet date of amounts expected to be recovered under the terms of insurance contracts.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.17) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 17 -Article 5
+ Details**Name:**us-gaap_EstimatedInsuranceRecoveries**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Reflects the estimated amount of loss from the specified contingency as of the balance sheet date.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14435-108349Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 9 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14557-108349
+ Details**Name:**us-gaap_LossContingencyEstimateOfPossibleLoss**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
This element represents the payments that the lessee is obligated to make or can be required to make in connection with a property under the terms of an agreement classified as an operating lease, excluding contingent rentals and a guarantee by the lessee of the lessor's debt and the lessee's obligation to pay (apart from the rental payments) executory costs such as insurance, maintenance, and taxes.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41499-112717Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 10 -Section 55 -Paragraph 40 -Subparagraph (Note 3) -URI http://asc.fasb.org/extlink&oid=6584154&loc=d3e38371-112697Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 10 -Section 25 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=7661868&loc=d3e34039-112682
+ Details**Name:**us-gaap_OperatingLeasesRentExpenseMinimumRentals**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                           |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Annual lease payments for land due on aggregate remaining years.
+ References
No definition available.
+ Details**Name:**wtr_AnnualLeasePaymentsForLandDueOnAggregateRemainingYears**Namespace Prefix:**wtr_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |
| X                                                                                                                                                                                                                                                   |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
capital investment in water mains
+ References
No definition available.
+ Details**Name:**wtr_CapitalInvestmentInWaterMains**Namespace Prefix:**wtr_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |
| X                                                                                                                                                                |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**wtr_CommitmentsAndContingenciesLineItems**Namespace Prefix:**wtr_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                         |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Contingent liability for self-insured employee medical benefit program
+ References
No definition available.
+ Details**Name:**wtr_ContingentLiabilityForSelfInsuredEmployeeMedicalBenefitProgram**Namespace Prefix:**wtr_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                           |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Estimated Annual Commitments To Purchase Water Through The Next Five Years
+ References
No definition available.
+ Details**Name:**wtr_EstimatedAnnualCommitmentsToPurchaseWaterThroughNextFiveYears**Namespace Prefix:**wtr_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                              |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Estimated Capital Expenditures Required Next Four Years
+ References
No definition available.
+ Details**Name:**wtr_EstimatedCapitalExpendituresRequiredNextFourYears**Namespace Prefix:**wtr_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**duration |
| X                                                                                                                                                                                                                       |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Lease Expiration Year
+ References
No definition available.
+ Details**Name:**wtr_LeaseExpirationYear**Namespace Prefix:**wtr_**Data Type:**xbrli:gYearItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                      |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Aggregate long term water purchase commitment, remaining years.
+ References
No definition available.
+ Details**Name:**wtr_LongTermPurchaseAggregateCommitmentRemainingYears**Namespace Prefix:**wtr_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**duration |
| X                                                                                                                                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Operating Lease Adjustment Period
+ References
No definition available.
+ Details**Name:**wtr_OperatingLeaseAdjustmentPeriod**Namespace Prefix:**wtr_**Data Type:**xbrli:durationItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                   |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Payment to support and promote conservation education and awareness
+ References
No definition available.
+ Details**Name:**wtr_PaymentToSupportAndPromoteConservationEducationAndAwareness**Namespace Prefix:**wtr_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |
| X                                                                                                                                                                                                                                                               |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Potenntial Fines For Alleged Violations
+ References
No definition available.
+ Details**Name:**wtr_PotenntialFinesForAllegedViolations**Namespace Prefix:**wtr_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |
| X                                                                                                                                                                                                                                |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Purchase Obligation Term
+ References
No definition available.
+ Details**Name:**wtr_PurchaseObligationTerm**Namespace Prefix:**wtr_**Data Type:**xbrli:durationItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                               |
|---------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_RangeAxis=us-gaap_MaximumMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                               |
|---------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_RangeAxis=us-gaap_MinimumMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |