XML 17 R54.htm IDEA: XBRL DOCUMENT v2.4.1.9
Segment Information (Narrative) (Details)
3 Months Ended
Mar. 31, 2015
segment
Segment Reporting Information [Line Items]  
Operating Segments 10us-gaap_NumberOfOperatingSegments
Reportable Segments 1us-gaap_NumberOfReportableSegments
Reportable Segment [Member]  
Segment Reporting Information [Line Items]  
Operating Segments 8us-gaap_NumberOfOperatingSegments
/ us-gaap_StatementBusinessSegmentsAxis
= us-gaap_ReportableSubsegmentsMember
Not Quantitatively Significant [Member]  
Segment Reporting Information [Line Items]  
Operating Segments 2us-gaap_NumberOfOperatingSegments
/ us-gaap_StatementBusinessSegmentsAxis
= wtr_NotQuantitativelySignificantMember