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Subordinated Debentures - Additional Information (Detail) $ in Thousands | 12 Months Ended
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Dec. 31, 2015 USD ($) trust | Dec. 31, 2014
Subordinated Borrowing [Line Items] |  |
Number of trusts | trust | 2 |
First Commonwealth Capital Trust III [Member] |  |
Subordinated Borrowing [Line Items] |  |
Redemption price as percentage of principal amount | 100.00% |
Deferred finance costs | $ 630 |
First Commonwealth Capital Trust II [Member] |  |
Subordinated Borrowing [Line Items] |  |
Redemption price as percentage of principal amount | 100.00% |
Deferred finance costs | $ 471 |
LIBOR [Member] | Subordinated Debt [Member] | First Commonwealth Capital Trust III [Member] |  |
Subordinated Borrowing [Line Items] |  |
Variable interest rate | 2.85% | 2.85%
LIBOR [Member] | Subordinated Debt [Member] | First Commonwealth Capital Trust II [Member] |  |
Subordinated Borrowing [Line Items] |  |
Variable interest rate | 2.85% | 2.85%

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- Definition Redemption Price As Percentage Of Principal Amount + References No definition available. + Details
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- Definition Percentage points added to the reference rate to compute the variable rate on the debt instrument. + References No definition available. + Details
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- Definition For an unclassified balance sheet, the amount as of the balance sheet date of capitalized costs associated with the issuance of debt instruments (for example, legal, accounting, underwriting, printing, and registration costs) that will be charged against earnings over the life of the debt instruments to which such costs pertain. Such amount is before the consideration of accumulated amortization. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28555-108399 + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Details
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- Details
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- Details
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