Parent Company Financial Information - Condensed Statements of Financial Condition (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Sep. 01, 2017	Dec. 31, 2016	Dec. 31, 2015
Assets:
Cash	$ 620,757	$ 723,866		$ 821,923	$ 561,179
Intangible assets	65,020	59,068
Other assets	7,248,870	6,999,540
Liabilities:
Trust preferred	67,011	67,011
Senior debt	98,388	98,171	$ 55,000
Interest payable	1,900	1,037
Other liabilities	85,831	88,748
Total liabilities	6,427,950	6,275,195
Stockholders’ Equity:
Common stock	569	563
Capital in excess of par value	349,810	336,271
Accumulated other comprehensive loss	(15,394)	(8,152)
Retained earnings	791,031	669,557
Treasury stock	(305,096)	(273,894)
Total stockholders’ equity	820,920	724,345		687,336	580,471
Total liabilities and stockholders’ equity	7,248,870	6,999,540
WSFS Financial Corporation
Assets:
Cash	30,581	37,344		$ 103,018	$ 26,456
Investment in subsidiaries	923,381	833,763
Investment in Capital Trust III	2,011	2,011
Intangible assets	31,050	17,465
Other assets	987,023	890,583
Liabilities:
Trust preferred	67,011	67,011
Senior debt	98,388	98,171
Interest payable	443	388
Other liabilities	261	668
Total liabilities	166,103	166,238
Stockholders’ Equity:
Common stock	569	563
Capital in excess of par value	349,810	336,271
Accumulated other comprehensive loss	(15,394)	(8,152)
Retained earnings	791,031	669,557
Treasury stock	(305,096)	(273,894)
Total stockholders’ equity	820,920	724,345
Total liabilities and stockholders’ equity	$ 987,023	$ 890,583