Parent Company Financial Information - Condensed Statements of Income (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income:
Unrealized (losses) gains on equity investments									$ 9,076	$ 333	$ 21
Noninterest income	$ 46,632	$ 49,171	$ 64,375	$ 40,847	$ 41,770	$ 62,346	$ 42,871	$ 41,122	201,025	188,109	162,541
Total revenue									715,430	709,201	455,514
Expense:
Interest expense	8,296	10,322	12,127	17,705	19,781	20,429	19,671	16,263	48,450	76,144	46,499
Other operating expense	(131,297)	(123,370)	(125,883)	(133,855)	(137,350)	(141,262)	(142,903)	(99,577)	(514,405)	(521,092)	(292,973)
Net expenses	(123,001)	(113,048)	(113,756)	(116,150)	(117,569)	(120,833)	(123,232)	(83,314)	(465,955)	(444,948)	(246,474)
Income before taxes	77,196	65,963	(10,058)	11,855	59,623	69,497	46,060	19,190	144,956	194,370	170,798
Income tax provision	$ 17,455	$ 15,140	$ (2,247)	$ 1,288	$ 14,199	$ 15,902	$ 10,091	$ 6,260	31,636	46,452	36,055
WSFS Financial Corporation
Income:
Interest income									356	5,589	1,591
Unrealized (losses) gains on equity investments									(1,617)	3,646	15,819
Noninterest income									208,762	240,408	28,038
Total revenue									207,501	249,643	45,448
Expense:
Interest expense									6,748	7,490	7,290
Other operating expense									2,553	259	245
Net expenses									9,301	7,749	7,535
Income before equity in undistributed income of subsidiaries									198,200	241,894	37,913
Equity in undistributed income (loss) of subsidiaries									(84,346)	(92,020)	97,626
Income before taxes									113,854	149,874	135,539
Income tax provision									(920)	1,065	796
Net income attributable to WSFS									$ 114,774	$ 148,809	$ 134,743