Summary of Significant Accounting Policies (Policies)	6 Months Ended
Jun. 30, 2018
Accounting Policies [Abstract]
Basis of presentation	Basis of presentation — The accompanying unaudited interim financial statements of WesBanco, Inc. and its consolidated subsidiaries (“WesBanco”) have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements and should be read in conjunction with our Annual Report on Form 10-K for the year ended December 31, 2017. WesBanco’s interim financial statements have been prepared following the significant accounting policies disclosed in Note 1 of the Notes to the Consolidated Financial Statements of its 2017 Annual Report on Form 10-K filed with the Securities and Exchange Commission. In the opinion of management, the accompanying interim financial information reflects all adjustments, including normal recurring adjustments, necessary to present fairly WesBanco’s financial position and results of operations for each of the interim periods presented. Certain prior period amounts have been reclassified to conform to the current period presentation. Such reclassifications had no impact on WesBanco’s net income and stockholders’ equity. Results of operations for interim periods are not necessarily indicative of the results of operations that may be expected for a full year.
Recent accounting pronouncements	Recent accounting pronouncements — In August 2017, the FASB issued ASU 2017-12, “Targeted Improvements to Accounting for Hedging Activities.” The new guidance will make more financial and nonfinancial hedging strategies eligible for hedge accounting. It also amends the presentation and disclosure requirements and changes how companies assess effectiveness. It is intended to more closely align hedge accounting with companies’ risk management strategies, simplify the application of hedge accounting, and increase transparency as to the scope and results of hedging programs. The guidance is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. Early adoption is permitted, including adoption in an interim period. WesBanco is currently assessing the impact of ASU 2017-12 on WesBanco’s Consolidated Financial Statements. In March 2017, the FASB issued ASU 2017-07 that changes how an employer presents the net periodic benefit cost in the income statement for an employer-sponsored defined benefit pension and/or other postretirement benefit plans. Employers will present the service cost component of net periodic benefit cost in the same income statement line item as other employee compensation costs arising from services rendered during the period. Only the service cost component will be eligible for capitalization in assets. Employers will present the other components of the net periodic benefit cost separately from the line items that includes the service cost outside of any subtotal of operating income, if one is presented. These components will not be eligible for capitalization in assets. For public business entities, the amendments in this update are effective for annual reporting periods beginning after December 15, 2017, including interim reporting periods within those annual reporting periods. Early adoption is permitted as of the beginning of an annual period (i.e., only in the first interim period). For WesBanco, this update was effective for the fiscal year beginning January 1, 2018. Upon adoption, WesBanco reclassified the service cost component from employee benefits to salaries and wages, which are both components of non-interest expense. The service cost component for the three and six months ended June 30, 2018 was $0.7 and $1.4 million, respectively. In January 2017, the FASB issued ASU 2017-01, which clarifies the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. ASU 2017-01 will be effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2017, which for WesBanco was effective for the fiscal year beginning January 1, 2018. The adoption of this pronouncement did not have a material impact on WesBanco’s Consolidated Financial Statements. In October 2016, the FASB issued ASU 2016-16 that provides the recognition of income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. Current guidance prohibits the recognition of current and deferred income taxes for an intra-entity asset transfer until the asset has been sold to an outside party. This prohibition on recognition is an exception to the principle of comprehensive recognition of current and deferred income taxes in generally accepted accounting principles. The exception has led to diversity in practice and is a source of complexity in financial reporting. FASB decided that an entity should recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. Consequently, the amendments in this update eliminate the exception for an intra-entity transfer of an asset other than inventory. The amendments in this update do not include new disclosure requirements; however, existing disclosure requirements might be applicable when accounting for the current and deferred income taxes for an intra-entity transfer of an asset other than inventory. For public business entities, the amendments in this update are effective for annual reporting periods beginning after December 15, 2017, including interim reporting periods within those annual reporting periods, which for WesBanco was effective for the fiscal year beginning January 1, 2018. The amendments in this update were to be applied on a modified retrospective basis through a cumulative-effect adjustment directly to retained earnings as of the beginning of the period of adoption. The adoption of this pronouncement did not have a material impact on WesBanco’s Consolidated Financial Statements. In August 2016, the FASB issued ASU 2016-15 that provides guidance for the classification of cash flows related to (1) debt prepayment or extinguishment costs, (2) settlement of zero-coupon debt instruments or other debt instruments with coupon rates that are insignificant in relation to the effective interest rate on the borrowing, (3) contingent consideration payments made after a business combination, (4) proceeds from the settlement of insurance claims, (5) proceeds from the settlement of corporate-owned life insurance policies, (6) distributions received from equity method investees, (7) beneficial interests in securitization transactions and (8) separately identifiable cash flows and application of the predominance principle. Public business entities must apply the new requirements for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years, which for WesBanco was effective for the fiscal year beginning January 1, 2018. The adoption of this pronouncement did not have a material impact on WesBanco’s Consolidated Financial Statements. In June 2016, the FASB issued ASU 2016-13 that will require entities to use a new forward-looking “expected loss” model on trade and other receivables, held-to-maturity debt securities, loans and other instruments that generally will result in the earlier recognition of allowances for credit losses. For available-for-sale debt securities with unrealized losses, entities will measure credit losses in a manner similar to what they do today, except that the losses will be recognized as allowances rather than reductions in the amortized cost of the securities. Entities will have to disclose significantly more information, including information they use to track credit quality by year of origination for most financing receivables. Public business entities must apply the new requirements for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years, which for WesBanco will be effective for the fiscal year beginning January 1, 2020. Early adoption is permitted for fiscal years beginning after December 15, 2018. WesBanco is currently evaluating the impact of the adoption of this pronouncement on WesBanco’s Consolidated Financial Statements. In February 2016, the FASB issued ASU 2016-02 that will require entities to recognize lease assets and lease liabilities on the balance sheet and disclose key information about leasing arrangements. The principal difference from previous guidance is that the lease assets and lease liabilities arising from operating leases were not previously recognized in the balance sheet. Public business entities must apply the new requirements for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early adoption is permitted. In January 2018, the FASB issued ASU 2018-01, which allows entities the option to apply the provisions of the new lease guidance at the effective date without adjusting the comparative periods presented. In July 2018, the FASB issued ASU 2018-10, which provides narrow-scope improvements to the lease standard. While we are currently assessing the impact of the adoption of this pronouncement, we expect the primary impact to our consolidated financial position upon adoption will be the recognition, on a discounted basis, of our minimum commitments under non-cancellable operating leases on our consolidated Balance Sheets resulting in the recording of right of use assets and lease obligations. In January 2016, the FASB issued ASU 2016-01 that will require entities to measure equity investments that do not result in consolidation and are not accounted for under the equity method at fair value and recognize any changes in fair value in net income unless the investments qualify for the new practicability exception. The standard does not change the guidance for classifying and measuring investments in debt securities and loans. Entities will have to record changes in instrument-specific credit risk for financial liabilities measured under the fair value option in other comprehensive income. Public business entities must apply the new requirements for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. In February 2018, the FASB issued ASU 2018-03, which clarifies certain aspects of the guidance issued in ASU 2016-01. WesBanco adopted these pronouncements as of January 1, 2018 and recognized a $1.1 million adjustment to retained earnings upon adoption of this pronouncement. In addition, WesBanco reclassified investment securities on the Consolidated Financial Statements into the following – equity securities, available-for-sale debt securities and held-to-maturity debt securities. In May 2014, the FASB issued ASU 2014-09 related to the recognition of revenue from contracts with customers. The new revenue pronouncement creates a single source of revenue guidance for all companies in all industries and is more principles-based than current revenue guidance. The pronouncement provides a five-step model for a company to recognize revenue when it transfers control of goods or services to customers at an amount that reflects the consideration to which it expects to be entitled in exchange for those goods or services. The five steps are, (1) identify the contract with the customer, (2) identify the separate performance obligations in the contract, (3) determine the transaction price, (4) allocate the transaction price to the separate performance obligations and (5) recognize revenue when each performance obligation is satisfied. On July 9, 2015, the FASB approved a one-year deferral of the effective date of the update. The update is effective for interim and annual reporting periods in fiscal years beginning after December 15, 2017. In March 2016, the FASB issued ASU 2016-08, which amends the principle versus agent guidance in the revenue standard. In April 2016, the FASB issued ASU 2016-10, which clarifies when promised goods or services are separately identifiable in the revenue standard. In May 2016, FASB issued ASU 2016-12, which provides narrow-scope improvements and practical expedients to the revenue standard. WesBanco adopted these pronouncements as of January 1, 2018 using the modified retrospective approach. WesBanco noted no material change to the timing of revenue recognition and there was no material impact on WesBanco’s Consolidated Financial Statements. See Note 9, Revenue Recognition for further discussion on revenue within the scope of ASC 606.

Recent accounting pronouncements — In August 2017, the FASB issued ASU 2017-12, “Targeted Improvements to Accounting for Hedging Activities.” The new guidance will make more financial and nonfinancial hedging strategies eligible for hedge accounting. It also amends the presentation and disclosure requirements and changes how companies assess effectiveness. It is intended to more closely align hedge accounting with companies’ risk management strategies, simplify the application of hedge accounting, and increase transparency as to the scope and results of hedging programs. The guidance is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. Early adoption is permitted, including adoption in an interim period. WesBanco is currently assessing the impact of ASU 2017-12 on WesBanco’s Consolidated Financial Statements.

In March 2017, the FASB issued ASU 2017-07 that changes how an employer presents the net periodic benefit cost in the income statement for an employer-sponsored defined benefit pension and/or other postretirement benefit plans. Employers will present the service cost component of net periodic benefit cost in the same income statement line item as other employee compensation costs arising from services rendered during the period. Only the service cost component will be eligible for capitalization in assets. Employers will present the other components of the net periodic benefit cost separately from the line items that includes the service cost outside of any subtotal of operating income, if one is presented. These components will not be eligible for capitalization in assets. For public business entities, the amendments in this update are effective for annual reporting periods beginning after December 15, 2017, including interim reporting periods within those annual reporting periods. Early adoption is permitted as of the beginning of an annual period (i.e., only in the first interim period). For WesBanco, this update was effective for the fiscal year beginning January 1, 2018. Upon adoption, WesBanco reclassified the service cost component from employee benefits to salaries and wages, which are both components of non-interest expense. The service cost component for the three and six months ended June 30, 2018 was $0.7 and $1.4 million, respectively.

In January 2017, the FASB issued ASU 2017-01, which clarifies the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. ASU 2017-01 will be effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2017, which for WesBanco was effective for the fiscal year beginning January 1, 2018. The adoption of this pronouncement did not have a material impact on WesBanco’s Consolidated Financial Statements.

In October 2016, the FASB issued ASU 2016-16 that provides the recognition of income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. Current guidance prohibits the recognition of current and deferred income taxes for an intra-entity asset transfer until the asset has been sold to an outside party. This prohibition on recognition is an exception to the principle of comprehensive recognition of current and deferred income taxes in generally accepted accounting principles. The exception has led to diversity in practice and is a source of complexity in financial reporting. FASB decided that an entity should recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. Consequently, the amendments in this update eliminate the exception for an intra-entity transfer of an asset other than inventory. The amendments in this update do not include new disclosure requirements; however, existing disclosure requirements might be applicable when accounting for the current and deferred income taxes for an intra-entity transfer of an asset other than inventory. For public business entities, the amendments in this update are effective for annual reporting periods beginning after December 15, 2017, including interim reporting periods within those annual reporting periods, which for WesBanco was effective for the fiscal year beginning January 1, 2018. The amendments in this update were to be applied on a modified retrospective basis through a cumulative-effect adjustment directly to retained earnings as of the beginning of the period of adoption. The adoption of this pronouncement did not have a material impact on WesBanco’s Consolidated Financial Statements.

In August 2016, the FASB issued ASU 2016-15 that provides guidance for the classification of cash flows related to (1) debt prepayment or extinguishment costs, (2) settlement of zero-coupon debt instruments or other debt instruments with coupon rates that are insignificant in relation to the effective interest rate on the borrowing, (3) contingent consideration payments made after a business combination, (4) proceeds from the settlement of insurance claims, (5) proceeds from the settlement of corporate-owned life insurance policies, (6) distributions received from equity method investees, (7) beneficial interests in securitization transactions and (8) separately identifiable cash flows and application of the predominance principle. Public business entities must apply the new requirements for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years, which for WesBanco was effective for the fiscal year beginning January 1, 2018. The adoption of this pronouncement did not have a material impact on WesBanco’s Consolidated Financial Statements.

In June 2016, the FASB issued ASU 2016-13 that will require entities to use a new forward-looking “expected loss” model on trade and other receivables, held-to-maturity debt securities, loans and other instruments that generally will result in the earlier recognition of allowances for credit losses. For available-for-sale debt securities with unrealized losses, entities will measure credit losses in a manner similar to what they do today, except that the losses will be recognized as allowances rather than reductions in the amortized cost of the securities. Entities will have to disclose significantly

more information, including information they use to track credit quality by year of origination for most financing receivables. Public business entities must apply the new requirements for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years, which for WesBanco will be effective for the fiscal year beginning January 1, 2020. Early adoption is permitted for fiscal years beginning after December 15, 2018. WesBanco is currently evaluating the impact of the adoption of this pronouncement on WesBanco’s Consolidated Financial Statements.

In February 2016, the FASB issued ASU 2016-02 that will require entities to recognize lease assets and lease liabilities on the balance sheet and disclose key information about leasing arrangements. The principal difference from previous guidance is that the lease assets and lease liabilities arising from operating leases were not previously recognized in the balance sheet. Public business entities must apply the new requirements for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early adoption is permitted. In January 2018, the FASB issued ASU 2018-01, which allows entities the option to apply the provisions of the new lease guidance at the effective date without adjusting the comparative periods presented. In July 2018, the FASB issued ASU 2018-10, which provides narrow-scope improvements to the lease standard. While we are currently assessing the impact of the adoption of this pronouncement, we expect the primary impact to our consolidated financial position upon adoption will be the recognition, on a discounted basis, of our minimum commitments under non-cancellable operating leases on our consolidated Balance Sheets resulting in the recording of right of use assets and lease obligations.

In January 2016, the FASB issued ASU 2016-01 that will require entities to measure equity investments that do not result in consolidation and are not accounted for under the equity method at fair value and recognize any changes in fair value in net income unless the investments qualify for the new practicability exception. The standard does not change the guidance for classifying and measuring investments in debt securities and loans. Entities will have to record changes in instrument-specific credit risk for financial liabilities measured under the fair value option in other comprehensive income. Public business entities must apply the new requirements for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. In February 2018, the FASB issued ASU 2018-03, which clarifies certain aspects of the guidance issued in ASU 2016-01. WesBanco adopted these pronouncements as of January 1, 2018 and recognized a $1.1 million adjustment to retained earnings upon adoption of this pronouncement. In addition, WesBanco reclassified investment securities on the Consolidated Financial Statements into the following – equity securities, available-for-sale debt securities and held-to-maturity debt securities.

In May 2014, the FASB issued ASU 2014-09 related to the recognition of revenue from contracts with customers. The new revenue pronouncement creates a single source of revenue guidance for all companies in all industries and is more principles-based than current revenue guidance. The pronouncement provides a five-step model for a company to recognize revenue when it transfers control of goods or services to customers at an amount that reflects the consideration to which it expects to be entitled in exchange for those goods or services. The five steps are, (1) identify the contract with the customer, (2) identify the separate performance obligations in the contract, (3) determine the transaction price, (4) allocate the transaction price to the separate performance obligations and (5) recognize revenue when each performance obligation is satisfied. On July 9, 2015, the FASB approved a one-year deferral of the effective date of the update. The update is effective for interim and annual reporting periods in fiscal years beginning after December 15, 2017. In March 2016, the FASB issued ASU 2016-08, which amends the principle versus agent guidance in the revenue standard. In April 2016, the FASB issued ASU 2016-10, which clarifies when promised goods or services are separately identifiable in the revenue standard. In May 2016, FASB issued ASU 2016-12, which provides narrow-scope improvements and practical expedients to the revenue standard. WesBanco adopted these pronouncements as of January 1, 2018 using the modified retrospective approach. WesBanco noted no material change to the timing of revenue recognition and there was no material impact on WesBanco’s Consolidated Financial Statements. See Note 9, Revenue Recognition for further discussion on revenue within the scope of ASC 606.