Basis of Presentation - Additional Information (Detail)	1 Months Ended	3 Months Ended		6 Months Ended
	May 31, 2015 $ / shares	Jun. 30, 2016 USD ($) Subsidiary $ / shares Office shares	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($) Office Subsidiary $ / shares shares	Jun. 30, 2015 USD ($)	Jun. 13, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($) $ / shares shares	Mar. 31, 2015 $ / shares shares
Basis Of Presentation [Line Items]
Number of unconsolidated affiliate | Office				1
Number of banking offices | Office		63		63
Common stock, shares authorized | shares		65,000,000		65,000,000				65,000,000	65,000,000
Common stock, par value | $ / shares	$ 0.01	$ 0.01		$ 0.01				$ 0.01	$ 0.01
Stock split description				Three-for-one stock split
Stock split conversion ratio	3
Stock dividend record date				May 04, 2015
Tax benefit recognized | $		$ (8,504,000)	$ (6,887,000)	$ (17,181,000)	$ (14,211,000)
Senior Unsecured Fixed - to - Floating Rate Notes [Member]
Basis Of Presentation [Line Items]
Senior unsecured fixed-to-floating rate notes, issued amount | $						$ 100,000,000
Senior unsecured notes, maturity date				Jun. 15, 2026
Interest rate on unsecured debt						4.50%
Senior unsecured notes, redemption beginning date				Jun. 15, 2021
Senior unsecured notes, redemption price percentage of principal				100.00%
Senior Unsecured Fixed - to - Floating Rate Notes [Member] | London Interbank Offered Rate (LIBOR) [Member]
Basis Of Presentation [Line Items]
Senior unsecured notes, variable rate description				A variable coupon rate of three-month LIBOR plus 3.30% from June 15, 2021 until maturity.
Senior unsecured notes, variable rate added to LIBOR				3.30%
Scenario, Previously Reported [Member]
Basis Of Presentation [Line Items]
Common stock, shares authorized | shares									20,000,000
Common stock, par value | $ / shares									$ 0.01
Accounting Standards Update 2015-03 [Member] | Other Assets [Member]
Basis Of Presentation [Line Items]
Unamortized debt issuance cost | $							$ (1,200,000)	$ (1,300,000)
Accounting Standards Update 2015-03 [Member] | Senior Debt [Member]
Basis Of Presentation [Line Items]
Unamortized debt issuance cost | $							(1,200,000)	(1,300,000)
Accounting Standards Update 2016-09 [Member]
Basis Of Presentation [Line Items]
Tax benefit recognized | $		$ 688,000		$ 688,000
Senior Debt Obligations [Member]
Basis Of Presentation [Line Items]
Unamortized debt issuance costs related to senior debt | $							$ 1,200,000	$ 1,300,000
Delaware [Member]
Basis Of Presentation [Line Items]
Number of banking offices | Office		44		44
Pennsylvania [Member]
Basis Of Presentation [Line Items]
Number of banking offices | Office		17		17
Virginia [Member]
Basis Of Presentation [Line Items]
Number of banking offices | Office		1		1
Nevada [Member]
Basis Of Presentation [Line Items]
Number of banking offices | Office		1		1
WSFS Financial Corporation [Member]
Basis Of Presentation [Line Items]
Number of wholly-owned subsidiaries | Subsidiary		3		3