Face (par) amount of debt instrument at time of issuance.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

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Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Period Type:	instant

- Definition

Write-off of amounts previously capitalized as debt issuance cost in an extinguishment of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.8)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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Balance Type:	debit
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- Definition

Basis Of Presentation [Line Items]

+ References

No definition available.

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- Definition

Number Of Office Locations

+ References

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- Definition

Number of Unconsolidated Affiliate

+ References

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+ Details

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Namespace Prefix:	wsfs_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number Of Wholly Owned Subsidiaries Of Company

+ References

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BASIS OF PRESENTATION (Detail)		3 Months Ended
BASIS OF PRESENTATION (Detail)	Sep. 01, 2017 USD ($)	Mar. 31, 2018 Subsidiary Office	Dec. 31, 2012 USD ($)
Basis Of Presentation [Line Items]
Number of unconsolidated affiliate		1
Number of banking offices		77
Write-off of unamortized debt issuance costs \| $	$ 700,000
Delaware
Basis Of Presentation [Line Items]
Number of banking offices		46
Pennsylvania
Basis Of Presentation [Line Items]
Number of banking offices		29
Virginia
Basis Of Presentation [Line Items]
Number of banking offices		1
Nevada
Basis Of Presentation [Line Items]
Number of banking offices		1
WSFS Financial Corporation
Basis Of Presentation [Line Items]
Number of wholly-owned subsidiaries \| Subsidiary		3
Senior notes due 2019
Basis Of Presentation [Line Items]
Senior unsecured fixed-to-floating rate notes, issued amount \| $			$ 55,000,000.0
Interest rate on unsecured debt			6.25%