GOODWILL AND INTANGIBLE ASSETS - Schedule of Allocation of Goodwill to Our Reportable Operating Segments for Purposes of Goodwill Impairment Testing (Detail)	3 Months Ended
	Mar. 31, 2020 USD ($)
Goodwill [Line Items]
Impairment loss	$ 0
Goodwill [Roll Forward]
Goodwill beginning balance	472,828,000
Remeasurement period adjustments	0
Goodwill ending balance	472,828,000
WSFS Bank
Goodwill [Roll Forward]
Goodwill beginning balance	452,629,000
Remeasurement period adjustments	0
Goodwill ending balance	452,629,000
Cash Connect
Goodwill [Roll Forward]
Goodwill beginning balance	0
Remeasurement period adjustments	0
Goodwill ending balance	0
Wealth Management
Goodwill [Roll Forward]
Goodwill beginning balance	20,199,000
Remeasurement period adjustments	0
Goodwill ending balance	$ 20,199,000