Segment Information - Details of Segment Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Interest income	$ 51,503	$ 43,055	$ 101,549	$ 85,906
Noninterest income	24,849	22,458	47,919	43,553
Total revenue	76,352	65,513	149,468	129,459
Interest expense	5,089	3,965	9,779	7,999
Noninterest expenses	44,027	38,654	87,226	77,567
Provision for loan losses	1,254	3,773	2,034	4,559
Total expenses	50,370	46,392	99,039	90,125
Income before taxes	25,982	19,121	50,429	39,334
Income tax provision	8,504	6,887	17,181	14,211
Net Income	17,478	12,234	33,248	25,123
Capital expenditures	2,645	2,082	3,878	2,816
Cash and cash equivalents	703,893	533,691	703,893	533,691	$ 561,179	$ 508,039
Goodwill	84,852		84,852		85,212
Other segment assets	5,045,362		5,045,362		4,938,246
Total assets	5,834,107		5,834,107		5,584,637
Scenario, Adjustment [Member]
Segment Reporting Information [Line Items]
Total assets					5,584,637
Inter-Segment Eliminations [Member]
Segment Reporting Information [Line Items]
Interest income	2,787	2,514	5,743	4,832
Noninterest income	2,246	2,241	4,523	4,211
Total revenue	5,033	4,755	10,266	9,043
Interest expense	2,787	2,514	5,743	4,832
Noninterest expenses	2,246	2,241	4,523	4,211
Total expenses	5,033	4,755	10,266	9,043
External Customer [Member]
Segment Reporting Information [Line Items]
Total revenue	81,385	70,268	159,734	138,502
Total expenses	55,403	51,147	109,305	99,168
WSFS Bank [Member]
Segment Reporting Information [Line Items]
Interest income	49,492	41,043	97,530	81,866
Noninterest income	10,173	9,482	20,025	18,671
Total revenue	59,665	50,525	117,555	100,537
Interest expense	4,896	3,822	9,393	7,734
Noninterest expenses	34,462	29,921	68,274	61,000
Provision for loan losses	1,191	3,610	2,006	4,343
Total expenses	40,549	37,353	79,673	73,077
Income before taxes	20,375	14,165	40,150	29,475
Capital expenditures	2,235	1,083	3,446	1,580
Cash and cash equivalents	84,919		84,919		65,663
Goodwill	79,718		79,718		80,078
Other segment assets	4,843,166		4,843,166		4,745,670
Total assets	5,007,803		5,007,803		4,891,411
WSFS Bank [Member] | Inter-Segment Eliminations [Member]
Segment Reporting Information [Line Items]
Interest income	1,135	876	2,196	1,747
Noninterest income	2,011	1,998	4,071	3,782
Total revenue	3,146	2,874	6,267	5,529
Interest expense	1,652	1,638	3,547	3,085
Noninterest expenses	235	243	452	429
Total expenses	1,887	1,881	3,999	3,514
WSFS Bank [Member] | External Customer [Member]
Segment Reporting Information [Line Items]
Total revenue	62,811	53,399	123,822	106,066
Total expenses	42,436	39,234	83,672	76,591
Cash Connect [Member]
Segment Reporting Information [Line Items]
Noninterest income	8,138	7,068	15,811	13,707
Total revenue	8,138	7,068	15,811	13,707
Noninterest expenses	4,831	4,350	9,681	8,525
Total expenses	4,831	4,350	9,681	8,525
Income before taxes	2,162	1,899	3,908	3,544
Capital expenditures	404	987	424	1,221
Cash and cash equivalents	617,339		617,339		493,165
Other segment assets	3,419		3,419
Total assets	620,758		620,758		493,165
Cash Connect [Member] | Inter-Segment Eliminations [Member]
Segment Reporting Information [Line Items]
Noninterest income	210	214	403	382
Total revenue	210	214	403	382
Interest expense	628	389	1,183	762
Noninterest expenses	727	644	1,442	1,258
Total expenses	1,355	1,033	2,625	2,020
Cash Connect [Member] | External Customer [Member]
Segment Reporting Information [Line Items]
Total revenue	8,348	7,282	16,214	14,089
Total expenses	6,186	5,383	12,306	10,545
Wealth Management [Member]
Segment Reporting Information [Line Items]
Interest income	2,011	2,012	4,019	4,040
Noninterest income	6,538	5,908	12,083	11,175
Total revenue	8,549	7,920	16,102	15,215
Interest expense	193	143	386	265
Noninterest expenses	4,734	4,383	9,271	8,042
Provision for loan losses	63	163	28	216
Total expenses	4,990	4,689	9,685	8,523
Income before taxes	3,445	3,057	6,371	6,315
Capital expenditures	6	12	8	15
Cash and cash equivalents	1,635		1,635		2,351
Goodwill	5,134		5,134		5,134
Other segment assets	198,777		198,777		192,576
Total assets	205,546		205,546		$ 200,061
Wealth Management [Member] | Inter-Segment Eliminations [Member]
Segment Reporting Information [Line Items]
Interest income	1,652	1,638	3,547	3,085
Noninterest income	25	29	49	47
Total revenue	1,677	1,667	3,596	3,132
Interest expense	507	487	1,013	985
Noninterest expenses	1,284	1,354	2,629	2,524
Total expenses	1,791	1,841	3,642	3,509
Wealth Management [Member] | External Customer [Member]
Segment Reporting Information [Line Items]
Total revenue	10,226	9,587	19,698	18,347
Total expenses	$ 6,781	$ 6,530	$ 13,327	$ 12,032