Benefit Plans - Additional Information (Detail) $ in Millions	9 Months Ended
Sep. 30, 2019 USD ($)
Compensation And Retirement Disclosure [Abstract]
Minimum required pension plan contribution	$ 4.8
Available credit balance	52.5
Expected voluntary contribution for the year 2019	$ 3.0

No definition available.

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- Definition

Amount of actuarial present value of benefits attributed to service rendered by employee for defined benefit plan.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of contributions received and expected to be received by defined benefit plan from employer in current fiscal year.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 6
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e2709-114920

+ Details

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- Definition

Amount of voluntary contributions received and expected to be received by defined benefit plan from employer in current fiscal year.

+ References

No definition available.

+ Details

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Namespace Prefix:	wsbc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration