Comprehensive Income/(Loss) - Components of Accumulated Other Comprehensive Income (Parenthetical) (Detail)	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement Of Income And Comprehensive Income [Abstract]
Percentage of Federal and State income tax rate	23.00%	23.00%	23.00%

Income tax expense benefit combined federal and state income tax rate.

No definition available.

Name:	wsbc_IncomeTaxExpenseBenefitCombinedFederalAndStateIncomeTaxRate
Namespace Prefix:	wsbc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration