Fair Value Measurement - Additional Information (Detail) - USD ($)	3 Months Ended	6 Months Ended	12 Months Ended
Jun. 30, 2018	Jun. 30, 2018	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Fair value transfer amount	$ 0	$ 0	$ 0

The amount of the transfers between levels of the fair value hierarchy.

No definition available.

Name:	wsbc_FairValueTransfersBetweenLevel
Namespace Prefix:	wsbc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration