FHLB and Other Short-Term Borrowings - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Federal Home Loan Bank Advances By Branch Of FHLB Bank And Other Borrowings [Line Items]
Borrowings	$ 968,946,000	$ 1,041,750,000
Weighted-average rate, Total	1.19%	1.17%
FHLB stock owned by WesBanco pledged as collateral on these advances	$ 46,400,000	$ 45,500,000
Remaining maximum borrowing capacity	1,700,000,000	1,100,000,000
Other short term borrowings	199,376,000	81,356,000
Securities sold under agreements to repurchase	$ 141,400,000	$ 81,400,000
Securities sold under agreements to repurchase, weighted average interest rate	0.38%	0.32%
Federal funds purchased	$ 58,000,000	$ 0
Securities sold under agreements to repurchase, interest rate	0.85%
Outstanding balance	$ 0	$ 0
Revolving Credit Facility [Member]
Federal Home Loan Bank Advances By Branch Of FHLB Bank And Other Borrowings [Line Items]
Revolving line of credit accrued interest at LIBOR rate, provides for aggregate outstanding borrowings	$ 25,000,000
Initiation date of revolving credit facility	Sep. 30, 2016