Segment Information - Details of Segment Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment Reporting Information [Line Items]
Interest income	$ 62,334	$ 51,503	$ 123,160	$ 101,549
Noninterest income	31,676	25,507	59,768	49,176
Total revenue	94,010	77,010	182,928	150,725
Interest expense	8,020	5,089	15,743	9,779
Noninterest expenses	52,727	44,685	104,233	88,483
Provision for loan losses	1,843	1,254	4,005	2,034
Total expenses	62,590	51,028	123,981	100,296
Income before taxes	31,420	25,982	58,947	50,429
Income tax provision	10,850	8,504	19,440	17,181
Net income	20,570	17,478	39,507	33,248
Capital expenditures	1,990	2,645	4,354	3,878
Inter-Segment Eliminations
Segment Reporting Information [Line Items]
Interest income	4,682	2,787	8,743	5,743
Noninterest income	2,153	2,246	4,544	4,523
Total revenue	6,835	5,033	13,287	10,266
Interest expense	4,682	2,787	8,743	5,743
Noninterest expenses	2,153	2,246	4,544	4,523
Total expenses	6,835	5,033	13,287	10,266
External Customer
Segment Reporting Information [Line Items]
Total revenue	100,845	82,043	196,215	160,991
Total expenses	69,425	56,061	137,268	110,562
WSFS Bank
Segment Reporting Information [Line Items]
Interest income	60,234	49,492	118,922	97,530
Noninterest income	12,049	10,173	22,216	20,025
Total revenue	72,283	59,665	141,138	117,555
Interest expense	7,739	4,896	15,202	9,393
Noninterest expenses	38,782	34,462	77,742	68,274
Provision for loan losses	1,316	1,191	3,032	2,006
Total expenses	47,837	40,549	95,976	79,673
Income before taxes	25,917	20,375	48,501	40,150
Capital expenditures	1,559	2,235	3,647	3,446
WSFS Bank | Inter-Segment Eliminations
Segment Reporting Information [Line Items]
Interest income	2,247	1,135	4,243	2,196
Noninterest income	1,906	2,011	4,070	4,071
Total revenue	4,153	3,146	8,313	6,267
Interest expense	2,435	1,652	4,500	3,547
Noninterest expenses	247	235	474	452
Total expenses	2,682	1,887	4,974	3,999
WSFS Bank | External Customer
Segment Reporting Information [Line Items]
Total revenue	76,436	62,811	149,451	123,822
Total expenses	50,519	42,436	100,950	83,672
Cash Connect
Segment Reporting Information [Line Items]
Interest income	0	0	0	0
Noninterest income	10,514	8,796	20,191	17,068
Total revenue	10,514	8,796	20,191	17,068
Interest expense	0	0	0	0
Noninterest expenses	6,591	5,489	12,726	10,938
Provision for loan losses	0	0	0	0
Total expenses	6,591	5,489	12,726	10,938
Income before taxes	1,875	2,162	3,488	3,908
Capital expenditures	68	404	90	424
Cash Connect | Inter-Segment Eliminations
Segment Reporting Information [Line Items]
Interest income	0	0	0	0
Noninterest income	207	210	398	403
Total revenue	207	210	398	403
Interest expense	1,582	628	2,987	1,183
Noninterest expenses	673	727	1,388	1,442
Total expenses	2,255	1,355	4,375	2,625
Cash Connect | External Customer
Segment Reporting Information [Line Items]
Total revenue	10,721	9,006	20,589	17,471
Total expenses	8,846	6,844	17,101	13,563
Wealth Management
Segment Reporting Information [Line Items]
Interest income	2,100	2,011	4,238	4,019
Noninterest income	9,113	6,538	17,361	12,083
Total revenue	11,213	8,549	21,599	16,102
Interest expense	281	193	541	386
Noninterest expenses	7,354	4,734	13,765	9,271
Provision for loan losses	527	63	973	28
Total expenses	8,162	4,990	15,279	9,685
Income before taxes	3,628	3,445	6,958	6,371
Capital expenditures	363	6	617	8
Wealth Management | Inter-Segment Eliminations
Segment Reporting Information [Line Items]
Interest income	2,435	1,652	4,500	3,547
Noninterest income	40	25	76	49
Total revenue	2,475	1,677	4,576	3,596
Interest expense	665	507	1,256	1,013
Noninterest expenses	1,233	1,284	2,682	2,629
Total expenses	1,898	1,791	3,938	3,642
Wealth Management | External Customer
Segment Reporting Information [Line Items]
Total revenue	13,688	10,226	26,175	19,698
Total expenses	$ 10,060	$ 6,781	$ 19,217	$ 13,327