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, 2019	Dec. 31, 2018	Dec. 31, 2017
Goodwill [Roll Forward]
Goodwill, beginning balance	$ 166,007	$ 166,007
Goodwill adjustments	0	0	$ (1,532)
Goodwill from business combinations	309,486
Effect of adjustments	(2,665)
Goodwill, ending balance	472,828	166,007	166,007
WSFS Bank
Goodwill [Roll Forward]
Goodwill, beginning balance	145,808	145,808
Goodwill adjustments		0
Goodwill from business combinations	309,486
Effect of adjustments	(2,665)
Goodwill, ending balance	452,629	145,808	145,808
Wealth Management
Goodwill [Roll Forward]
Goodwill, beginning balance	20,199	20,199
Goodwill adjustments		0
Goodwill from business combinations	0
Effect of adjustments	0
Goodwill, ending balance	$ 20,199	$ 20,199	$ 20,199