Goodwill and Intangibles - Schedule of Allocation of Goodwill to Our Reportable Operating Segments for Purposes of Goodwill Impairment Testing (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Goodwill [Roll Forward]
Goodwill, beginning balance	$ 472,828	$ 166,007
Goodwill from business combinations		309,486
Remeasurement period adjustments	0	(2,665)
Goodwill, ending balance	472,828	472,828
WSFS Bank
Goodwill [Roll Forward]
Goodwill, beginning balance	452,629	145,808
Goodwill from business combinations		309,486
Remeasurement period adjustments	0	(2,665)
Goodwill, ending balance	452,629	452,629
Wealth Management
Goodwill [Roll Forward]
Goodwill, beginning balance	20,199	20,199
Goodwill from business combinations		0
Remeasurement period adjustments	0	0
Goodwill, ending balance	$ 20,199	$ 20,199