| **New Accounting Pronouncements (Notes)**               | 6 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               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| **Accounting Changes and Error Corrections [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           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| New Accounting Pronouncements                           | New Accounting PronouncementsIn January 2014, the FASB issued ASU 2014-01, "Investments - Equity Method and Joint Ventures (Topic 323)," which permits reporting entities to make an accounting policy election to account for their investments in qualified affordable housing projects using the proportional amortization method if certain conditions are met.  The proportional amortization method allows an entity to amortize the initial cost of the investment in proportion to the tax credits and other tax benefits received and recognizes the net investment performance in the income statement as a component of income tax expense (benefit).  This amendment is effective for interim and annual periods beginning after December 15, 2014.  The adoption of this ASU is not expected to have a material impact on First Commonwealth’s financial condition or results of operations.In January 2014, the FASB issued ASU 2014-04, "Receivables - Troubled Debt Restructurings by Creditors (Subtopic 310-40)."  This amendment clarifies that an in-substance repossession or foreclosure occurs and a creditor is considered to have received physical possession of property upon either, 1. the creditor obtaining legal title to the residential real estate property upon completion of a foreclosure, or 2. the borrower conveying all interest in the residential real estate property to the creditor to satisfy that loan through completion of a deed in lieu of foreclosure or through a similar legal agreement.  Interim and annual disclosure of both the amount of foreclosed residential real estate property held by the creditor and the recorded investment in consumer mortgage loans collateralized by residential real estate property that are in the process of foreclosure according to local requirements of the applicable jurisdiction are required.  This amendment is effective for annual periods beginning after December 15, 2014 and for interim periods within annual periods beginning after December 15, 2015.  The adoption of this ASU is not expected to have a material impact on First Commonwealth’s financial condition or results of operations.In April 2014, the FASB issued ASU 2014-08, “Presentation of Financial Statements (Topic 205) and Property, Plant, and Equipment (Topic 360)."  This amendment changes the reporting requirements for discontinued operations.  A disposal of a component of an entity or group of components of an entity is required to be reported in discontinued operations if the disposal represents a strategic shift resulting in a major effect on the entity's operations and financial results when any of the following occurs: 1. the component or group of components of an entity meets the criteria to be classified as held for sale, 2. the component or group of components of an entity is disposed of by sale, or 3. the component or group of components of an entity is disposed of other than by sale.  If one of these criteria are met, the entity will present the assets and liabilities of a disposal group that includes a discontinued operation separately in the asset and liability sections of the statement of financial position for each comparative period along with additional footnote disclosure.  This amendment is effective for annual periods beginning on or after December 15, 2014 and interim periods within annual periods beginning on or after December 15, 2015.   The adoption of this ASU is not expected to have a material impact on First Commonwealth’s financial condition or results of operations.In June 2014, the FASB issued ASU 2014-11, "Transfers and Servicing (Topic 860)," which requires two accounting changes.  One changes the accounting for repurchase-to-maturity transactions to secured borrowing accounting and the other for requires separate accounting for a transfer of a financial asset executed contemporaneously with a repurchase agreement with the same counterparty in regards to repurchase financing arrangements, which will result in secured borrowing accounting for the repurchase agreement.  The Update requres diclosure for certain transactions comprising a transfer of a financial asset accounted for as a sale and an agreement with the same transferee entered into in contemplation of the initial transfer that results in the transferor retaining substantially all of the exposure to economic return.  The amendment also requires disclosure for repurchase agreements, securities lending transactions, and repurchase-to-maturity transactions that are accounted for as secured borrowings.  This amendment will be effective for public entities for the first interim or annual period beginning after December 15, 2014.  The adoption of this ASU is not expected to have a material impact on First Commonwealth’s financial condition or results of operations.In June 2014, the FASB issued ASU 2014-12, "Compensation - Stock Compensation (Topic 718)," which requires that a performance target that affects vesting and that could be achieved after the requisite service period be treated as a performance condition.  As such, the performance target should not be reflected in estimating the grant-date fair value of the award.  Compensation cost should be recognized in the period in which it becomes probable that the performance target will be achieved and should represent the compensation cost attributable to the period(s) for which the requisite service has already been rendered.  If the performance target becomes probable of being achieved before the end of the requisite service period, the remaining unrecognized compensation cost should be recognized prospectively over the remaining requisite service period.  This amendment is effective for annual periods and interim periods within those annual periods beginning after December 15, 2015 with earlier adoption permitted.  The adoption of this ASU is not expected to have a material impact on First Commonwealth’s financial condition or results of operations. |

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| - Definition
Disclosure of accounting policy pertaining to new accounting pronouncements that may impact the entity's financial reporting. Includes, but is not limited to, quantification of the expected or actual impact.
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No definition available.
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