Loans and the Allowance for Credit Losses - Recognition of Interest Income on Nonperforming Loans (Detail) - Nonperforming Loans [Member] - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Impaired [Line Items]
Average nonperforming loans	$ 42,594	$ 40,306	$ 39,623
Amount of contractual interest income on nonperforming loans	2,827	3,047	2,631
Amount of interest income recognized on nonperforming loans	$ 260	$ 341	$ 665

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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- Definition

Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5212-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5258-111524

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- Definition

Amount of interest income recognized that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

+ References

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- Definition

Loans and leases receivable nonperforming contractual interest income.

+ References

No definition available.

+ Details

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Namespace Prefix:	wsbc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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