SEGMENT INFORMATION - Details of Segment Information - Statement of Financial Condition (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Cash and cash equivalents	$ 505,110	$ 571,752
Goodwill	472,828	472,828
Other segment assets	11,300,952	11,211,722
Total assets	12,278,890	12,256,302
Capital expenditures	2,531	14,198
WSFS Bank
Segment Reporting Information [Line Items]
Cash and cash equivalents	177,508	202,792
Goodwill	452,629	452,629
Other segment assets	11,064,324	10,982,681
Total assets	11,694,461	11,638,102
Capital expenditures	2,282	11,806
Cash Connect
Segment Reporting Information [Line Items]
Cash and cash equivalents	320,077	357,494
Goodwill	0	0
Other segment assets	6,983	6,555
Total assets	327,060	364,049
Capital expenditures	211	2,120
Wealth Management
Segment Reporting Information [Line Items]
Cash and cash equivalents	7,525	11,466
Goodwill	20,199	20,199
Other segment assets	229,645	222,486
Total assets	257,369	254,151
Capital expenditures	$ 38	$ 272