Consolidated Statements Of Cash Flow (Parenthetical) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018
Consolidated Statements Of Cash Flow [Abstract]
Debt component of allowance for funds used during construction	$ 3,253	$ 2,550

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