Segment Information - Details of Segment Information (Detail) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Mar. 31, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Interest income	$ 43,055	$ 39,413	$ 39,413	$ 85,906	$ 77,198
Noninterest income	22,458	19,623	19,623	43,553	37,987
Total revenue	65,513		59,036	129,459	115,185
Interest expense	3,965	3,936		7,999	7,677
Noninterest expenses	38,654	35,224		77,567	69,108
Provision for loan losses	3,773	50		4,559	2,680
Total expenses	46,392	39,210		90,125	79,465
Income before taxes	19,121	19,826		39,334	35,720
Income tax provision	6,887	7,101		14,211	6,084
Net Income	12,234	12,725		25,123	29,636
Capital expenditures	2,882	848		3,699	1,385
Cash and cash equivalents	533,691	475,189		533,691	475,189	$ 508,039	$ 484,426
Goodwill	48,987			48,987		48,651
Other segment assets	4,494,805			4,494,805		4,296,630
Total assets	5,077,483			5,077,483		4,853,320
Inter-Segment Eliminations [Member]
Segment Reporting Information [Line Items]
Interest income	2,514		2,176	4,832	4,428
Noninterest income	2,241		1,942	4,211	3,899
Total revenue	4,755	4,118		9,043	8,327
Interest expense	2,514	2,176		4,832	4,428
Noninterest expenses	2,241	1,942		4,211	3,899
Total expenses	4,755	4,118		9,043	8,327
External Customer [Member]
Segment Reporting Information [Line Items]
Total revenue	70,268	63,154		138,502	123,512
Total expenses	51,147	43,328		99,168	87,792
WSFS Bank [Member]
Segment Reporting Information [Line Items]
Interest income	41,043		37,480	81,866	73,401
Noninterest income	9,482		8,778	18,671	17,173
Total revenue	50,525		46,258	100,537	90,574
Interest expense	3,822	3,831		7,734	7,461
Noninterest expenses	29,921	28,316		61,000	55,634
Provision for loan losses	3,610	(201)		4,343	2,122
Total expenses	37,353	31,946		73,077	65,217
Income before taxes	14,165	15,284		29,475	27,258
Capital expenditures	299	815		1,116	1,293
Cash and cash equivalents	89,298			89,298		73,395
Goodwill	43,853			43,853		43,517
Other segment assets	4,304,300			4,304,300		4,107,212
Total assets	4,437,451			4,437,451		4,224,124
WSFS Bank [Member] | Inter-Segment Eliminations [Member]
Segment Reporting Information [Line Items]
Interest income	876		834	1,747	1,665
Noninterest income	1,998		1,711	3,782	3,449
Total revenue	2,874	2,545		5,529	5,114
Interest expense	1,638	1,342		3,085	2,763
Noninterest expenses	243	231		429	450
Total expenses	1,881	1,573		3,514	3,213
WSFS Bank [Member] | External Customer [Member]
Segment Reporting Information [Line Items]
Total revenue	53,399	48,803		106,066	95,688
Total expenses	39,234	33,519		76,591	68,430
Cash Connect [Member]
Segment Reporting Information [Line Items]
Noninterest income	7,068		6,320	13,707	12,334
Total revenue	7,068		6,320	13,707	12,334
Noninterest expenses	4,350	3,882		8,525	7,432
Total expenses	4,350	3,882		8,525	7,432
Income before taxes	1,899	1,721		3,544	3,461
Capital expenditures	2,570	33		2,570	89
Cash and cash equivalents	442,229			442,229		431,527
Other segment assets						2,006
Total assets	442,229			442,229		433,533
Cash Connect [Member] | Inter-Segment Eliminations [Member]
Segment Reporting Information [Line Items]
Noninterest income	214		204	382	397
Total revenue	214	204		382	397
Interest expense	389	328		762	659
Noninterest expenses	644	593		1,258	1,179
Total expenses	1,033	921		2,020	1,838
Cash Connect [Member] | External Customer [Member]
Segment Reporting Information [Line Items]
Total revenue	7,282	6,524		14,089	12,731
Total expenses	5,383	4,803		10,545	9,270
Wealth Management [Member]
Segment Reporting Information [Line Items]
Interest income	2,012		1,933	4,040	3,797
Noninterest income	5,908		4,525	11,175	8,480
Total revenue	7,920		6,458	15,215	12,277
Interest expense	143	105		265	216
Noninterest expenses	4,383	3,026		8,042	6,042
Provision for loan losses	163	251		216	558
Total expenses	4,689	3,382		8,523	6,816
Income before taxes	3,057	2,821		6,315	5,001
Capital expenditures	13			13	3
Cash and cash equivalents	2,164			2,164		3,117
Goodwill	5,134			5,134		5,134
Other segment assets	190,505			190,505		187,412
Total assets	197,803			197,803		$ 195,663
Wealth Management [Member] | Inter-Segment Eliminations [Member]
Segment Reporting Information [Line Items]
Interest income	1,638		1,342	3,085	2,763
Noninterest income	29		$ 27	47	53
Total revenue	1,667	1,369		3,132	2,816
Interest expense	487	506		985	1,006
Noninterest expenses	1,354	1,118		2,524	2,270
Total expenses	1,841	1,624		3,509	3,276
Wealth Management [Member] | External Customer [Member]
Segment Reporting Information [Line Items]
Total revenue	9,587	7,827		18,347	15,093
Total expenses	$ 6,530	$ 5,006		$ 12,032	$ 10,092