| **Taxes Other Than Income Taxes (Details) - USD ($) $ in Thousands** | 12 Months Ended |
|----------------------------------------------------------------------|-----------------|
||
| **Taxes Other Than Income Taxes [Line Items]**                       |            |   |   |
| Total taxes other than income taxes                                  | $ 59,762        | $ 56,628 | $ 56,385 |
| Property [Member]                                                    |            |   |   |
| **Taxes Other Than Income Taxes [Line Items]**                       |            |   |   |
| Total taxes other than income taxes                                  | 27,469          | 25,810 | 26,788 |
| Gross Receipts, Excise And Franchise [Member]                        |            |   |   |
| **Taxes Other Than Income Taxes [Line Items]**                       |            |   |   |
| Total taxes other than income taxes                                  | 14,521          | 13,458 | 12,510 |
| Payroll [Member]                                                     |            |   |   |
| **Taxes Other Than Income Taxes [Line Items]**                       |            |   |   |
| Total taxes other than income taxes                                  | 9,789           | 9,477 | 9,772 |
| Regulatory Assessments [Member]                                      |            |   |   |
| **Taxes Other Than Income Taxes [Line Items]**                       |            |   |   |
| Total taxes other than income taxes                                  | 2,752           | 2,552 | 2,630 |
| Pumping Fees [Member]                                                |            |   |   |
| **Taxes Other Than Income Taxes [Line Items]**                       |            |   |   |
| Total taxes other than income taxes                                  | 4,978           | 5,057 | 4,571 |
| Other [Member]                                                       |            |   |   |
| **Taxes Other Than Income Taxes [Line Items]**                       |            |   |   |
| Total taxes other than income taxes                                  | $ 253           | $ 274 | $ 114 |

| 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 Taxes [Line Items]
+ References
No definition available.
+ Details**Name:**wtr_TaxesOtherThanIncomeTaxesLineItems**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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