| **Taxes Other Than Income Taxes (Details) - USD ($) $ in Thousands** | 3 Months Ended | 6 Months Ended |
|----------------------------------------------------------------------|----------------|----------------|
||
| **Taxes Other Than Income [Line Items]**                             |           |           |   |   |
| Total taxes other than income                                        | $ 14,419       | $ 14,242       | $ 29,156 | $ 28,382 |
| Property [Member]                                                    |           |           |   |   |
| **Taxes Other Than Income [Line Items]**                             |           |           |   |   |
| Total taxes other than income                                        | 6,867          | 6,928          | 13,652 | 13,113 |
| Gross Receipts, Excise And Franchise [Member]                        |           |           |   |   |
| **Taxes Other Than Income [Line Items]**                             |           |           |   |   |
| Total taxes other than income                                        | 3,363          | 3,113          | 6,538 | 6,059 |
| Payroll [Member]                                                     |           |           |   |   |
| **Taxes Other Than Income [Line Items]**                             |           |           |   |   |
| Total taxes other than income                                        | 2,132          | 2,299          | 5,256 | 5,635 |
| Regulatory Assessments [Member]                                      |           |           |   |   |
| **Taxes Other Than Income [Line Items]**                             |           |           |   |   |
| Total taxes other than income                                        | 630            | 681            | 1,259 | 1,352 |
| Pumping Fees [Member]                                                |           |           |   |   |
| **Taxes Other Than Income [Line Items]**                             |           |           |   |   |
| Total taxes other than income                                        | 1,350          | 1,140          | 2,294 | 2,059 |
| Other [Member]                                                       |           |           |   |   |
| **Taxes Other Than Income [Line Items]**                             |           |           |   |   |
| Total taxes other than income                                        | $ 77           | $ 81           | $ 157 | $ 164 |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of operating expense for taxes other than income taxes of regulated operation.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.2(b)) -URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688
+ Details**Name:**us-gaap_UtilitiesOperatingExpenseTaxes**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |
| X                                                                                                                                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Taxes Other Than Income [Line Items]
+ References
No definition available.
+ Details**Name:**wtr_TaxesOtherThanIncomeLineItems**Namespace Prefix:**wtr_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                        |
|------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_StatementScenarioAxis=wtr_PropertyMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                               |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_StatementScenarioAxis=wtr_GrossReceiptsExciseAndFranchiseMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                       |
|-----------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_StatementScenarioAxis=wtr_PayrollMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                     |
|-------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_StatementScenarioAxis=wtr_RegulatoryAssessmentsMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                           |
|---------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_StatementScenarioAxis=wtr_PumpingFeesMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                          |
|--------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_StatementScenarioAxis=wtr_OtherTaxesMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |