SEGMENT INFORMATION - Segment Results (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
Interest income	$ 125,883	$ 142,903	$ 259,738	$ 242,480
Noninterest income	64,375	42,871	105,222	83,993
Total revenue	190,258	185,774	364,960	326,473
Interest expense	12,127	19,671	29,832	35,934
Noninterest expenses	93,435	107,848	181,931	205,440
Provision for credit losses	94,754	12,195	151,400	19,849
Total expenses	200,316	139,714	363,163	261,223
(Loss) income before taxes	(10,058)	46,060	1,797	65,250
Income tax (benefit) provision	(2,247)	10,091	(959)	16,351
Net (loss) income	(7,811)	35,969	2,756	48,899
Less: Net loss attributable to noncontrolling interest	(700)	(231)	(1,060)	(324)
Net (loss) income attributable to WSFS	(7,111)	36,200	3,816	49,223
Inter-Segment Eliminations
Segment Reporting Information [Line Items]
Interest income	3,616	7,397	8,408	15,194
Noninterest income	4,077	2,559	7,386	4,805
Total revenue	7,693	9,956	15,794	19,999
Interest expense	3,616	7,397	8,408	15,194
Noninterest expenses	4,077	2,559	7,386	4,805
Total expenses	7,693	9,956	15,794	19,999
Operating Segments
Segment Reporting Information [Line Items]
Interest income	125,883	142,903	259,738	242,480
Noninterest income	64,375	42,871	105,222	83,993
Total revenue	197,951	195,730	380,754	346,472
Interest expense	12,127	19,671	29,832	35,934
Noninterest expenses	93,435	107,848	181,931	205,440
Total expenses	208,009	149,670	378,957	281,222
(Loss) income before taxes	(10,058)	46,060	1,797	65,250
WSFS Bank
Segment Reporting Information [Line Items]
Total revenue	168,014	159,101	317,395	273,311
Provision for credit losses	93,819	12,239	148,853	19,525
Total expenses	185,267	121,936	330,133	226,935
WSFS Bank | Inter-Segment Eliminations
Segment Reporting Information [Line Items]
Interest income	937	3,345	2,880	7,137
Noninterest income	3,542	2,156	6,449	4,039
Total revenue	4,479	5,501	9,329	11,176
Interest expense	2,679	4,052	5,528	8,057
Noninterest expenses	535	403	937	766
Total expenses	3,214	4,455	6,465	8,823
WSFS Bank | Operating Segments
Segment Reporting Information [Line Items]
Interest income	123,710	140,231	255,019	237,177
Noninterest income	44,304	18,870	62,376	36,134
Total revenue	172,493	164,602	326,724	284,487
Interest expense	11,659	18,282	28,406	33,418
Noninterest expenses	79,789	91,415	152,874	173,992
Total expenses	188,481	126,391	336,598	235,758
(Loss) income before taxes	(15,988)	38,211	(9,874)	48,729
Cash Connect
Segment Reporting Information [Line Items]
Total revenue	9,008	13,355	20,687	25,757
Provision for credit losses	0	0	0	0
Total expenses	6,413	8,893	14,636	16,923
Cash Connect | Inter-Segment Eliminations
Segment Reporting Information [Line Items]
Interest income	237	0	237	0
Noninterest income	188	192	417	369
Total revenue	425	192	654	369
Interest expense	131	2,203	1,085	4,761
Noninterest expenses	899	698	1,640	1,243
Total expenses	1,030	2,901	2,725	6,004
Cash Connect | Operating Segments
Segment Reporting Information [Line Items]
Interest income	0	0	0	0
Noninterest income	9,008	13,355	20,687	25,757
Total revenue	9,433	13,547	21,341	26,126
Interest expense	0	0	0	0
Noninterest expenses	6,413	8,893	14,636	16,923
Total expenses	7,443	11,794	17,361	22,927
(Loss) income before taxes	1,990	1,753	3,980	3,199
Wealth Management
Segment Reporting Information [Line Items]
Total revenue	13,236	13,318	26,878	27,405
Provision for credit losses	935	(44)	2,547	324
Total expenses	8,636	8,885	18,394	17,365
Wealth Management | Inter-Segment Eliminations
Segment Reporting Information [Line Items]
Interest income	2,442	4,052	5,291	8,057
Noninterest income	347	211	520	397
Total revenue	2,789	4,263	5,811	8,454
Interest expense	806	1,142	1,795	2,376
Noninterest expenses	2,643	1,458	4,809	2,796
Total expenses	3,449	2,600	6,604	5,172
Wealth Management | Operating Segments
Segment Reporting Information [Line Items]
Interest income	2,173	2,672	4,719	5,303
Noninterest income	11,063	10,646	22,159	22,102
Total revenue	16,025	17,581	32,689	35,859
Interest expense	468	1,389	1,426	2,516
Noninterest expenses	7,233	7,540	14,421	14,525
Total expenses	12,085	11,485	24,998	22,537
(Loss) income before taxes	$ 3,940	$ 6,096	$ 7,691	$ 13,322