Borrowed Funds - Additional Information (Detail) - USD ($)		12 Months Ended
	Jun. 13, 2016	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2005
Repurchase Agreement Counterparty [Line Items]
Stock in Federal Home Loan Bank of Pittsburgh, at cost		$ 21,097,000	$ 19,259,000
Federal funds purchased		$ 195,000,000	$ 157,975,000
Federal funds rate on securities purchased (as percent)		1.60%	2.52%
Securities sold under agreements to repurchase		$ 0	$ 0
Senior debt		98,605,000	98,388,000
Write-off of unamortized debt issuance costs		0	0	$ 695,000
Senior unsecured notes, amount	$ 100,000,000.0
Collateralized borrowings		$ 16,000,000.0	$ 47,900,000
Average rates on borrowings (as percent)		0.30%	0.12%
Federal Reserve Bank of Philadelphia
Repurchase Agreement Counterparty [Line Items]
Loans pledged as collateral		$ 429,000,000.0	$ 176,400,000
Borrowed funds		$ 0	0
4.50% Senior Unsecured Notes Mature on 2026
Repurchase Agreement Counterparty [Line Items]
Interest rate on unsecured debt (as percent)	4.50%
Senior unsecured notes, percentage of principle amount to be redeemed (as percent)	100.00%
4.50% Senior Unsecured Notes Mature on 2026 | LIBOR Rate
Repurchase Agreement Counterparty [Line Items]
Variable interest rate (as percent)	3.30%
WSFS Capital Trust III
Repurchase Agreement Counterparty [Line Items]
Aggregate principal amount of Pooled Floating Rate Securities					$ 67,000,000.0
WSFS Capital Trust III | LIBOR Rate
Repurchase Agreement Counterparty [Line Items]
Variable interest rate (as percent)					1.77%
Federal Home Loan Bank
Repurchase Agreement Counterparty [Line Items]
Percentage of member asset value (as percent)		0.10%
Percentage of advances outstanding (as percent)		4.00%
Stock in Federal Home Loan Bank of Pittsburgh, at cost		$ 21,100,000	19,300,000
Dividends from the FHLB		$ 1,500,000	$ 1,500,000
Minimum
Repurchase Agreement Counterparty [Line Items]
Interest rates on advances from FHLB (as percent)		1.50%
Maximum
Repurchase Agreement Counterparty [Line Items]
Interest rates on advances from FHLB (as percent)		2.79%