Mergers and Acquisitions - Calculation of Purchase Price and Resulting Goodwill Relating to ESB Acquisition (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	0 Months Ended
Mar. 31, 2015	Feb. 10, 2015
Fair value of:
Goodwill recognized	$ 168,900us-gaap_GoodwillAcquiredDuringPeriod
ESB Financial Corporation [Member]
Purchase Price:
Fair value of WesBanco shares issued, (net of equity issuance costs of $0.1 million)		293,933
Cash consideration for outstanding ESB shares, options and restricted stock		37,036
Settlement of pre-existing loan to ESB		8,000
Total purchase price		338,969
Fair value of:
Tangible assets acquired		1,859,865
Core deposit and other intangible assets acquired		5,346
Liabilities assumed		(1,703,616)
Net cash received in the acquisition		8,485
Fair value of net assets acquired		170,080
Goodwill recognized		$ 168,889

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

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Amount of equity interests of the acquirer, including instruments or interests issued or issuable in consideration for the business combination.

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Amount of liabilities incurred by the acquirer as part of consideration transferred in a business combination.

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Amount of intangible assets, excluding goodwill, acquired at the acquisition date.

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Amount recognized as of the acquisition date for the identifiable assets acquired in excess of (less than) the aggregate liabilities assumed.

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Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

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The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

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