Employee Benefit Plans - Fair Values of the Wesbanco's Pension Plan Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Total defined benefit pension plan assets	$ 169,261	$ 141,108
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total defined benefit pension plan assets	123,506	99,148
Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total defined benefit pension plan assets	45,755	41,960
Registered Investment Companies [Member]
Defined Benefit Plan Disclosure [Line Items]
Total defined benefit pension plan assets	47,699	39,021
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	47,699	39,021
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total defined benefit pension plan assets	75,807	60,127
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	75,807	60,127
Corporate Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total defined benefit pension plan assets	16,122	16,980
Corporate Debt Securities [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total defined benefit pension plan assets	16,122	16,980
Municipal Obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Total defined benefit pension plan assets	3,313	2,930
Municipal Obligations [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total defined benefit pension plan assets	3,313	2,930
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	26,320	22,050
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	$ 26,320	$ 22,050