SEGMENT INFORMATION - Segment Results (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Interest income	$ 123,370	$ 141,262	$ 383,108	$ 383,742
Noninterest income	49,171	62,346	154,393	146,339
Total revenue	172,541	203,608	537,501	530,081
Interest expense	10,322	20,429	40,154	56,363
Noninterest expenses	93,540	109,561	275,471	315,001
Provision for credit losses	2,716	4,121	154,116	23,970
Total expenses	106,578	134,111	469,741	395,334
Income before taxes	65,963	69,497	67,760	134,747
Income tax provision	15,140	15,902	14,181	32,253
Net income	50,823	53,595	53,579	102,494
Less: Net loss attributable to noncontrolling interest	(322)	(287)	(1,382)	(611)
Net income attributable to WSFS	51,145	53,882	54,961	103,105
Capital expenditures for the period ended			3,480	10,701
Operating Segments
Segment Reporting Information [Line Items]
Interest income	123,370	141,262	383,108	383,742
Noninterest income	49,171	62,346	154,393	146,339
Total revenue	180,282	215,115	561,036	561,587
Interest expense	10,322	20,429	40,154	56,363
Noninterest expenses	93,540	109,561	275,471	315,001
Total expenses	114,319	145,618	493,276	426,840
Income before taxes	65,963	69,497	67,760	134,747
Capital expenditures for the period ended	650	5,260	3,480	10,701
Inter-Segment Eliminations
Segment Reporting Information [Line Items]
Interest income	3,686	8,447	12,094	23,641
Noninterest income	4,055	3,060	11,441	7,865
Total revenue	7,741	11,507	23,535	31,506
Interest expense	3,686	8,447	12,094	23,641
Noninterest expenses	4,055	3,060	11,441	7,865
Total expenses	7,741	11,507	23,535	31,506
WSFS Bank
Segment Reporting Information [Line Items]
Total revenue	146,780	177,148	464,175	450,459
Provision for credit losses	1,324	3,954	150,177	23,479
Total expenses	90,787	116,156	420,920	343,091
WSFS Bank | Operating Segments
Segment Reporting Information [Line Items]
Interest income	121,179	138,585	376,198	375,762
Noninterest income	25,601	38,563	87,977	74,697
Total revenue	151,104	182,486	477,828	466,973
Interest expense	9,994	19,056	38,400	52,474
Noninterest expenses	79,469	93,146	232,343	267,138
Total expenses	94,204	122,325	430,802	358,083
Income before taxes	56,900	60,161	47,026	108,890
Capital expenditures for the period ended	640	3,920	3,077	9,160
WSFS Bank | Inter-Segment Eliminations
Segment Reporting Information [Line Items]
Interest income	965	2,855	3,845	9,992
Noninterest income	3,359	2,483	9,808	6,522
Total revenue	4,324	5,338	13,653	16,514
Interest expense	2,721	5,592	8,249	13,649
Noninterest expenses	696	577	1,633	1,343
Total expenses	3,417	6,169	9,882	14,992
Cash Connect
Segment Reporting Information [Line Items]
Total revenue	10,157	13,067	30,844	38,824
Provision for credit losses	0	0	0	0
Total expenses	6,537	9,132	21,173	26,055
Cash Connect | Operating Segments
Segment Reporting Information [Line Items]
Interest income	0	0	0	0
Noninterest income	10,157	13,067	30,844	38,824
Total revenue	10,600	13,324	31,941	39,450
Interest expense	0	0	0	0
Noninterest expenses	6,537	9,132	21,173	26,055
Total expenses	7,507	11,542	24,868	34,469
Income before taxes	3,093	1,782	7,073	4,981
Capital expenditures for the period ended	0	1,340	256	1,411
Cash Connect | Inter-Segment Eliminations
Segment Reporting Information [Line Items]
Interest income	244	0	481	0
Noninterest income	199	257	616	626
Total revenue	443	257	1,097	626
Interest expense	172	1,730	1,257	6,491
Noninterest expenses	798	680	2,438	1,923
Total expenses	970	2,410	3,695	8,414
Wealth Management
Segment Reporting Information [Line Items]
Total revenue	15,604	13,393	42,482	40,798
Provision for credit losses	1,392	167	3,939	491
Total expenses	9,254	8,823	27,648	26,188
Wealth Management | Operating Segments
Segment Reporting Information [Line Items]
Interest income	2,191	2,677	6,910	7,980
Noninterest income	13,413	10,716	35,572	32,818
Total revenue	18,578	19,305	51,267	55,164
Interest expense	328	1,373	1,754	3,889
Noninterest expenses	7,534	7,283	21,955	21,808
Total expenses	12,608	11,751	37,606	34,288
Income before taxes	5,970	7,554	13,661	20,876
Capital expenditures for the period ended	10	0	147	130
Wealth Management | Inter-Segment Eliminations
Segment Reporting Information [Line Items]
Interest income	2,477	5,592	7,768	13,649
Noninterest income	497	320	1,017	717
Total revenue	2,974	5,912	8,785	14,366
Interest expense	793	1,125	2,588	3,501
Noninterest expenses	2,561	1,803	7,370	4,599
Total expenses	$ 3,354	$ 2,928	$ 9,958	$ 8,100