Employee Benefit Plans - Fair Values of the Wesbanco's Pension Plan Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Total defined benefit pension plan assets	$ 185,300	$ 169,261
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total defined benefit pension plan assets	143,323	123,506
Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total defined benefit pension plan assets	41,977	45,755
Registered Investment Companies [Member]
Defined Benefit Plan Disclosure [Line Items]
Total defined benefit pension plan assets	58,101	47,699
Registered Investment Companies [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total defined benefit pension plan assets	58,101	47,699
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total defined benefit pension plan assets	85,222	75,807
Equity Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total defined benefit pension plan assets	85,222	75,807
Corporate Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total defined benefit pension plan assets	21,170	16,122
Corporate Debt Securities [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total defined benefit pension plan assets	21,170	16,122
Municipal Obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Total defined benefit pension plan assets	2,382	3,313
Municipal Obligations [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total defined benefit pension plan assets	2,382	3,313
Residential Mortgage-Backed Securities and Collateralized Mortgage Obligations of Government Sponsored Entities and Agencies [Member]
Defined Benefit Plan Disclosure [Line Items]
Total defined benefit pension plan assets	18,425	26,320
Residential Mortgage-Backed Securities and Collateralized Mortgage Obligations of Government Sponsored Entities and Agencies [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total defined benefit pension plan assets	$ 18,425	$ 26,320