BORROWED FUNDS - Narrative (Details) - USD ($)			11 Months Ended	12 Months Ended
	Jan. 01, 2022	Dec. 03, 2020	Dec. 14, 2022	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2005	Dec. 15, 2022
Repurchase Agreement Counterparty [Line Items]
FHLB advances, weighted average interest rate (as a percent)				4.33%
Stock in Federal Home Loan Bank of Pittsburgh, at cost				$ 11,805,000	$ 15,398,000
Securities sold under agreements to repurchase				0	0
Collateralized borrowings				23,100,000	586,000,000.0
Other borrowed funds
Repurchase Agreement Counterparty [Line Items]
Outstanding borrowings				23,102,000	586,038,000
Federal Reserve Bank of Philadelphia
Repurchase Agreement Counterparty [Line Items]
Loans and securities pledged as collateral				2,500,000,000	2,100,000,000
Federal Reserve Bank of Philadelphia | Other borrowed funds
Repurchase Agreement Counterparty [Line Items]
Outstanding borrowings				$ 0	565,000,000.0
SOFR
Repurchase Agreement Counterparty [Line Items]
Variable interest rate (as a percent)				2.41%
WSFS Capital Trust III | Trust Preferred Borrowings | LIBOR
Repurchase Agreement Counterparty [Line Items]
Variable interest rate (as a percent)						1.77%
Trusts
Repurchase Agreement Counterparty [Line Items]
Trust common securities owned	$ 800,000
Aggregate principal amount of Pooled Floating Rate Securities	12,500,000
Floating rate common securities issued	400,000
FHLB Advances
Repurchase Agreement Counterparty [Line Items]
Stock in Federal Home Loan Bank of Pittsburgh, at cost				$ 11,800,000	15,400,000
Dividends from the FHLB				$ 1,500,000	1,100,000
Junior Subordinated Debt
Repurchase Agreement Counterparty [Line Items]
Interest rate on unsecured debt (as a percent)				6.77%
Junior Subordinated Debt | SOFR
Repurchase Agreement Counterparty [Line Items]
Variable interest rate (as a percent)				2.41%
Junior Subordinated Debt | Trusts
Repurchase Agreement Counterparty [Line Items]
Trust capital securities issued	11,900,000
Trust capital securities issued net	23,800,000
Senior Notes 2030
Repurchase Agreement Counterparty [Line Items]
Interest rate on unsecured debt (as a percent)		2.75%
Debt instrument, face amount		$ 150,000,000.0
Redemption price (as a percent)		100.00%
Debt issuance costs, gross				$ 148,600,000	148,400,000
Senior Notes 2030 | SOFR
Repurchase Agreement Counterparty [Line Items]
Variable interest rate (as a percent)		2.485%
Senior Notes 2025
Repurchase Agreement Counterparty [Line Items]
Debt instrument, face amount	$ 30,000,000.0
Senior Notes 2025 | LIBOR
Repurchase Agreement Counterparty [Line Items]
Variable interest rate (as a percent)	3.068%
Senior Notes 2027
Repurchase Agreement Counterparty [Line Items]
Variable interest rate (as a percent)			4.25%
Interest rate on unsecured debt (as a percent)							6.67%
Debt instrument, face amount	$ 70,000,000.0
Carrying value of securities purchased under agreements				$ 70,000,000.0	$ 70,000,000.0
Senior Notes 2027 | SOFR
Repurchase Agreement Counterparty [Line Items]
Variable interest rate (as a percent)	2.31%
Minimum
Repurchase Agreement Counterparty [Line Items]
FHLB advances, weighted average interest rate (as a percent)				3.77%
Maximum
Repurchase Agreement Counterparty [Line Items]
FHLB advances, weighted average interest rate (as a percent)				4.72%