Goodwill and Intangible Assets - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2017 USD ($) Segment	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 166,007,000	$ 167,539,000	$ 85,212,000
Impairment losses related to goodwill	$ 0	0
Number of operating segments | Segment	3
Amortization expense on other intangible assets	$ 3,078,000	2,438,000	1,847,000
Impairment of other intangible assets	0	0
WSFS Financial Corporation
Finite-Lived Intangible Assets [Line Items]
Goodwill	145,800,000
Other Intangible Assets
Finite-Lived Intangible Assets [Line Items]
Amortization expense on other intangible assets	$ 3,000,000	$ 2,400,000	$ 2,000,000