Goodwill and Intangible Assets - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2019 USD ($) segment	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 472,828,000	$ 166,007,000	$ 166,007,000
Impairment losses related to goodwill	$ 0	0
Number of operating segments | segment	3
Amortization expense on other intangible assets	$ 11,113,000	2,942,000	3,078,000
Impairment of other intangible assets	0	0
Other Intangible Assets
Finite-Lived Intangible Assets [Line Items]
Amortization expense on other intangible assets	9,700,000	2,900,000	3,000,000.0
WSFS Bank
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 452,629,000	$ 145,808,000	$ 145,808,000