Quarterly Financial Summary (Unaudited) (Details) - USD ($) $ / shares in Units, $ 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
Quarterly Financial Information Disclosure [Abstract]
Interest income	$ 131,297	$ 123,370	$ 125,883	$ 133,855	$ 137,350	$ 141,262	$ 142,903	$ 99,577	$ 514,405	$ 521,092	$ 292,973
Interest expense	8,296	10,322	12,127	17,705	19,781	20,429	19,671	16,263	48,450	76,144	46,499
Net interest income	123,001	113,048	113,756	116,150	117,569	120,833	123,232	83,314	465,955	444,948	246,474
Provision for credit losses	(936)	2,716	94,754	56,646	1,590	4,121	12,195	7,654	153,180	25,560	13,170
Net interest income after provision for credit losses	123,937	110,332	19,002	59,504	115,979	116,712	111,037	75,660	312,775	419,388	233,304
Noninterest income	46,632	49,171	64,375	40,847	41,770	62,346	42,871	41,122	201,025	188,109	162,541
Noninterest expenses	93,373	93,540	93,435	88,496	98,126	109,561	107,848	97,592	368,844	413,127	225,047
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
Net income	59,741	50,823	(7,811)	10,567	45,424	53,595	35,969	12,930	113,320	147,918	134,743
Less: Net loss attributable to noncontrolling interest	(72)	(322)	(700)	(360)	(280)	(287)	(231)	(93)	(1,454)	(891)	0
Net income attributable to WSFS	$ 59,813	$ 51,145	$ (7,111)	$ 10,927	$ 45,704	$ 53,882	$ 36,200	$ 13,023	$ 114,774	$ 148,809	$ 134,743
Earnings Per Share [Abstract]
Basic (in dollars per share)	$ 1.20	$ 1.01	$ (0.14)	$ 0.21	$ 0.88	$ 1.02	$ 0.68	$ 0.34	$ 2.27	$ 3.02	$ 4.27
Diluted (in dollars per share)	$ 1.20	$ 1.01	$ (0.14)	$ 0.21	$ 0.88	$ 1.02	$ 0.68	$ 0.33	$ 2.27	$ 3.00	$ 4.19