Consolidated Statements Of Cash Flow (Parenthetical) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Consolidated Statements Of Cash Flow [Abstract]
Debt component of allowance for funds used during construction	$ 296	$ 367

Debt component of allowance for funds used during construction

No definition available.

Name:	wtr_DebtComponentOfAllowanceForFundsUsedDuringConstruction
Namespace Prefix:	wtr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration