Basis of Presentation - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2017 USD ($) Subsidiary Office	Dec. 31, 2016 USD ($)	Jun. 13, 2016 USD ($)	Dec. 31, 2012 USD ($)
Basis Of Presentation [Line Items]
Number of unconsolidated affiliate	1
Number of banking offices	77
Senior debt | $	$ 152,177,000	$ 152,050,000
Senior Unsecured Fixed - to - Floating Rate Notes
Basis Of Presentation [Line Items]
Senior unsecured fixed-to-floating rate notes, issued amount | $			$ 100,000,000
Interest rate on unsecured debt			4.50%
Senior unsecured notes, redemption price percentage of principal	100.00%
Senior Unsecured Fixed - to - Floating Rate Notes | London Interbank Offered Rate (LIBOR)
Basis Of Presentation [Line Items]
Senior unsecured notes, variable rate added to LIBOR	3.30%
Delaware
Basis Of Presentation [Line Items]
Number of banking offices	46
Pennsylvania
Basis Of Presentation [Line Items]
Number of banking offices	29
Virginia
Basis Of Presentation [Line Items]
Number of banking offices	1
Nevada
Basis Of Presentation [Line Items]
Number of banking offices	1
WSFS Financial Corporation
Basis Of Presentation [Line Items]
Number of wholly-owned subsidiaries | Subsidiary	3
Senior notes due 2019
Basis Of Presentation [Line Items]
Interest rate on unsecured debt				6.25%
Senior debt | $				$ 55,000,000.0