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, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill [Roll Forward]
Goodwill, Beginning balance	$ 167,539	$ 85,212
Goodwill from business combinations	0	80,215
Remeasurement adjustments	(1,532)	2,112	$ 136
Goodwill, Ending balance	166,007	167,539	85,212
WSFS Bank
Goodwill [Roll Forward]
Goodwill, Beginning balance	147,396	80,078
Goodwill from business combinations	0	65,206
Remeasurement adjustments	(1,588)	2,112
Goodwill, Ending balance	145,808	147,396	80,078
Cash Connect
Goodwill [Roll Forward]
Goodwill, Beginning balance	0	0
Goodwill from business combinations	0	0
Remeasurement adjustments	0	0
Goodwill, Ending balance	0	0	0
Wealth Management
Goodwill [Roll Forward]
Goodwill, Beginning balance	20,143	5,134
Goodwill from business combinations	0	15,009
Remeasurement adjustments	56	0
Goodwill, Ending balance	$ 20,199	$ 20,143	$ 5,134