Loans and the Allowance for Credit Losses - Summary of Age Analysis of Loan Categories (Parenthetical) (Detail)	12 Months Ended
Dec. 31, 2019
Receivables [Abstract]
Past due loans excluded TDRs past due and accruing	90 days

Loans past due and accruing interest excluding TDRS.

No definition available.

Name:	wsbc_LoansPastDueAndAccruingInterestExcludingTDRS
Namespace Prefix:	wsbc_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration