| **Taxes Other Than Income Taxes (Details) (USD $)In Thousands, unless otherwise specified** | 3 Months Ended |
|---------------------------------------------------------------------------------------------|----------------|
||
| **Taxes Other Than Income Taxes [Line Items]**                                              |           |   |
| Utilities Operating Expense, Taxes                                                          | $ 12,102       | $ 13,398 |
| Property [Member]                                                                           |           |   |
| **Taxes Other Than Income Taxes [Line Items]**                                              |           |   |
| Utilities Operating Expense, Taxes                                                          | 4,824          | 6,443 |
| Capital Stock [Member]                                                                      |           |   |
| **Taxes Other Than Income Taxes [Line Items]**                                              |           |   |
| Utilities Operating Expense, Taxes                                                          | 501            | 534 |
| Gross Receipts, Excise And Franchise [Member]                                               |           |   |
| **Taxes Other Than Income Taxes [Line Items]**                                              |           |   |
| Utilities Operating Expense, Taxes                                                          | 2,779          | 2,681 |
| Payroll [Member]                                                                            |           |   |
| **Taxes Other Than Income Taxes [Line Items]**                                              |           |   |
| Utilities Operating Expense, Taxes                                                          | 2,654          | 2,420 |
| Other [Member]                                                                              |           |   |
| **Taxes Other Than Income Taxes [Line Items]**                                              |           |   |
| Utilities Operating Expense, Taxes                                                          | $ 1,344        | $ 1,320 |

| 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=26872669&loc=d3e20235-122688
+ Details**Name:**us-gaap_UtilitiesOperatingExpenseTaxes**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |
| X                                                                                                                                                              |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**wtr_TaxesOtherThanIncomeTaxesLineItems**Namespace Prefix:**wtr_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |