Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ 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
Numerator:
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
Denominator:
Weighted average shares (in shares)									50,510	49,298	31,570
Dilutive potential common shares (in shares)									37	256	597
Weighted average fully diluted shares (in shares)									50,547	49,554	32,167
Earnings per share:
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
Outstanding common stock equivalents having no dilutive effect (in shares)									12	1	18