| **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                                        | $ 14,829       | $ 14,419       | $ 29,796 | $ 29,156 |
| Property [Member]                                                    |           |           |   |   |
| **Taxes Other Than Income [Line Items]**                             |           |           |   |   |
| Total taxes other than income                                        | 6,775          | 6,867          | 13,524 | 13,652 |
| Gross Receipts, Excise And Franchise [Member]                        |           |           |   |   |
| **Taxes Other Than Income [Line Items]**                             |           |           |   |   |
| Total taxes other than income                                        | 3,789          | 3,363          | 7,053 | 6,538 |
| Payroll [Member]                                                     |           |           |   |   |
| **Taxes Other Than Income [Line Items]**                             |           |           |   |   |
| Total taxes other than income                                        | 2,180          | 2,132          | 5,455 | 5,256 |
| Regulatory Assessments [Member]                                      |           |           |   |   |
| **Taxes Other Than Income [Line Items]**                             |           |           |   |   |
| Total taxes other than income                                        | 627            | 630            | 1,254 | 1,259 |
| Pumping Fees [Member]                                                |           |           |   |   |
| **Taxes Other Than Income [Line Items]**                             |           |           |   |   |
| Total taxes other than income                                        | 1,424          | 1,350          | 2,415 | 2,294 |
| Other [Member]                                                       |           |           |   |   |
| **Taxes Other Than Income [Line Items]**                             |           |           |   |   |
| Total taxes other than income                                        | $ 34           | $ 77           | $ 95 | $ 157 |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of operating expense for taxes other than income taxes of regulated operation.
+ References
Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.2(b)) -URI http://asc.fasb.org/extlink&oid=115205541&loc=SL114868664-224227
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| 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                                                                                                                                        |
|------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                               |
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| X                                                                                                                                       |
|-----------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                     |
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| X                                                                                                                                           |
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| X                                                                                                                                          |
|--------------------------------------------------------------------------------------------------------------------------------------------|
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