Segment Information - Capital Expenditures (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Cash and cash equivalents	$ 571,752	$ 620,757
Goodwill	472,828	166,007	$ 166,007
Other segment assets	11,211,722	6,462,106
Total assets	12,256,302	7,248,870
Capital expenditures	14,198	5,498
WSFS Bank
Segment Reporting Information [Line Items]
Cash and cash equivalents	202,792	115,147
Goodwill	452,629	145,808	$ 145,808
Other segment assets	10,982,681	6,225,820
Total assets	11,638,102	6,486,775
Capital expenditures	11,806	4,779
Cash Connect
Segment Reporting Information [Line Items]
Cash and cash equivalents	357,494	491,863
Goodwill	0	0
Other segment assets	6,555	7,743
Total assets	364,049	499,606
Capital expenditures	2,120	375
Wealth Management
Segment Reporting Information [Line Items]
Cash and cash equivalents	11,466	13,747
Goodwill	20,199	20,199
Other segment assets	222,486	228,543
Total assets	254,151	262,489
Capital expenditures	$ 272	$ 344