| **Segment Information (Narrative) (Details)**  | 12 Months Ended |
|------------------------------------------------|-----------------|
||
| **Segment Reporting Information [Line Items]** |            |
| Operating Segments                             | 10              |
| Reportable Segments                            | 1               |
| Regulated Segment [Member]                     |            |
| **Segment Reporting Information [Line Items]** |            |
| Operating Segments                             | 8               |
| Not Quantitatively Significant [Member]        |            |
| **Segment Reporting Information [Line Items]** |            |
| Operating Segments                             | 2               |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues.
+ References
No definition available.
+ Details**Name:**us-gaap_NumberOfOperatingSegments**Namespace Prefix:**us-gaap_**Data Type:**xbrli:integerItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.
+ References
No definition available.
+ Details**Name:**us-gaap_NumberOfReportableSegments**Namespace Prefix:**us-gaap_**Data Type:**xbrli:integerItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                            |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.
+ References
No definition available.
+ Details**Name:**us-gaap_SegmentReportingInformationLineItems**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                        |
|----------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_StatementBusinessSegmentsAxis=wtr_RegulatedSegmentMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                    |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_StatementBusinessSegmentsAxis=wtr_NotQuantitativelySignificantMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |