Associate (Employee) Benefit Plans - Additional Information (Detail)	3 Months Ended
Mar. 31, 2016
Postemployment Benefits [Abstract]
Amortization of unrecognized gains losses exceed percentage	10.00%

Defined Benefit Plan Amortization Of Unrecognized Gains Losses Exceed Percentage

No definition available.

Name:	wsfs_DefinedBenefitPlanAmortizationOfUnrecognizedGainsLossesExceedPercentage
Namespace Prefix:	wsfs_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration