Comprehensive Income/(Loss) - Components of Accumulated Other Comprehensive Income (Parenthetical) (Detail)	3 Months Ended
Jun. 30, 2018	Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
Percentage of Federal and State income tax rate	23.00%	37.00%

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