Segment Information - Details of Segment Information- Statement of Financial Condition (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Cash and cash equivalents	$ 733,365	$ 821,923	$ 813,405	$ 561,179
Goodwill	166,007	167,539
Other segment assets	5,975,972	5,775,808
Total assets	6,875,344	6,765,270
WSFS Bank
Segment Reporting Information [Line Items]
Cash and cash equivalents	94,169	100,893
Goodwill	145,808	147,396
Other segment assets	5,757,941	5,545,611
Total assets	5,997,918	5,793,900
Cash Connect
Segment Reporting Information [Line Items]
Cash and cash equivalents	631,883	717,643
Goodwill	0	0
Other segment assets	2,983	3,533
Total assets	634,866	721,176
Wealth Management
Segment Reporting Information [Line Items]
Cash and cash equivalents	7,313	3,387
Goodwill	20,199	20,143
Other segment assets	215,048	226,664
Total assets	$ 242,560	$ 250,194