SEGMENT INFORMATION - Segment Results (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting Information [Line Items]
Interest income	$ 141,262	$ 75,415	$ 383,742	$ 215,179
Noninterest income	62,346	41,901	146,339	124,355
Total revenue	203,608	117,316	530,081	339,534
Interest expense	20,429	12,318	56,363	33,379
Noninterest expenses	109,561	52,454	315,001	163,697
Provision for loan losses	4,121	3,716	23,970	9,864
Total expenses	134,111	68,488	395,334	206,940
Income before taxes	69,497	48,828	134,747	132,594
Income tax provision	15,902	9,893	32,253	27,569
Net income	53,595	38,935	102,494	105,025
Less: Net loss attributable to noncontrolling interest	(287)	0	(611)	0
Net income attributable to WSFS	53,882	38,935	103,105	105,025
Inter-Segment Eliminations
Segment Reporting Information [Line Items]
Interest income	8,447	7,022	23,641	18,588
Noninterest income	3,060	2,358	7,865	7,137
Total revenue	11,507	9,380	31,506	25,725
Interest expense	8,447	7,022	23,641	18,588
Noninterest expenses	3,060	2,358	7,865	7,137
Total expenses	11,507	9,380	31,506	25,725
Operating Segments
Segment Reporting Information [Line Items]
Total revenue	215,115	126,696	561,587	365,259
Total expenses	145,618	77,868	426,840	232,665
Income before taxes	69,497	48,828	134,747	132,594
WSFS Bank
Segment Reporting Information [Line Items]
Interest income	138,585	72,836	375,762	207,725
Noninterest income	38,563	18,524	74,697	57,175
Total revenue	177,148	91,360	450,459	264,900
Interest expense	19,056	11,461	52,474	31,563
Noninterest expenses	93,146	44,922	267,138	126,862
Provision for loan losses	3,954	3,776	23,479	9,721
Total expenses	116,156	60,159	343,091	168,146
WSFS Bank | Inter-Segment Eliminations
Segment Reporting Information [Line Items]
Interest income	2,855	4,002	9,992	10,535
Noninterest income	2,483	2,122	6,522	6,449
Total revenue	5,338	6,124	16,514	16,984
Interest expense	5,592	3,020	13,649	8,053
Noninterest expenses	577	236	1,343	688
Total expenses	6,169	3,256	14,992	8,741
WSFS Bank | Operating Segments
Segment Reporting Information [Line Items]
Total revenue	182,486	97,484	466,973	281,884
Total expenses	122,325	63,415	358,083	176,887
Income before taxes	60,161	34,069	108,890	104,997
Cash Connect
Segment Reporting Information [Line Items]
Interest income	0	0	0	0
Noninterest income	13,067	13,026	38,824	36,707
Total revenue	13,067	13,026	38,824	36,707
Interest expense	0	0	0	0
Noninterest expenses	9,132	8,133	26,055	23,357
Provision for loan losses	0	0	0	0
Total expenses	9,132	8,133	26,055	23,357
Cash Connect | Inter-Segment Eliminations
Segment Reporting Information [Line Items]
Interest income	0	0	0	0
Noninterest income	257	200	626	581
Total revenue	257	200	626	581
Interest expense	1,730	2,885	6,491	7,460
Noninterest expenses	680	627	1,923	1,936
Total expenses	2,410	3,512	8,414	9,396
Cash Connect | Operating Segments
Segment Reporting Information [Line Items]
Total revenue	13,324	13,226	39,450	37,288
Total expenses	11,542	11,645	34,469	32,753
Income before taxes	1,782	1,581	4,981	4,535
Wealth Management
Segment Reporting Information [Line Items]
Interest income	2,677	2,579	7,980	7,454
Noninterest income	10,716	10,351	32,818	30,473
Total revenue	13,393	12,930	40,798	37,927
Interest expense	1,373	857	3,889	1,816
Noninterest expenses	7,283	(601)	21,808	13,478
Provision for loan losses	167	(60)	491	143
Total expenses	8,823	196	26,188	15,437
Wealth Management | Inter-Segment Eliminations
Segment Reporting Information [Line Items]
Interest income	5,592	3,020	13,649	8,053
Noninterest income	320	36	717	107
Total revenue	5,912	3,056	14,366	8,160
Interest expense	1,125	1,117	3,501	3,075
Noninterest expenses	1,803	1,495	4,599	4,513
Total expenses	2,928	2,612	8,100	7,588
Wealth Management | Operating Segments
Segment Reporting Information [Line Items]
Total revenue	19,305	15,986	55,164	46,087
Total expenses	11,751	2,808	34,288	23,025
Income before taxes	$ 7,554	$ 13,178	$ 20,876	$ 23,062