Commitments and Contingent Liabilities - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Commitments And Contingencies Disclosure [Abstract]
Allowance for credit losses associated with loan commitments	$ 0.3	$ 0.3
Estimated fair value of standby letters of credit	$ 0.1	$ 0.1

Allowance For Credit Losses Associated With Loan Commitments

No definition available.

Name:	wsbc_AllowanceForCreditLossesAssociatedWithLoanCommitments
Namespace Prefix:	wsbc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant