XML 26 R104.htm IDEA: XBRL DOCUMENT
v2.4.1.9

Subordinated Debentures - Additional Information (Detail) (USD $) | 12 Months Ended | 0 Months Ended | 12 Months Ended
--- | --- | --- | ---
Dec. 31, 2014 | Apr. 02, 2013 | Dec. 31, 2013
First Commonwealth Capital Trust [Member] |  |  |
Subordinated Borrowing [Line Items] |  |  |
Percentage of common equity owned by First Commonwealth | 100.00%fcf_PercentageOfEachTrustCommonEquityOwnedByCorporation / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = fcf_FirstCommonwealthCapitalTrustMember |  |
First Commonwealth Capital Trust III [Member] |  |  |
Subordinated Borrowing [Line Items] |  |  |
Redemption price as percentage of principal amount | 100.00%fcf_RedemptionPriceAsPercentageOfPrincipalAmount / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = fcf_FirstCommonwealthCapitalTrustThreeMember |  |
Deferred finance costs | $ 630,000us-gaap_DeferredFinanceCostsGross / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = fcf_FirstCommonwealthCapitalTrustThreeMember |  |
First Commonwealth Capital Trust II [Member] |  |  |
Subordinated Borrowing [Line Items] |  |  |
Redemption price as percentage of principal amount | 100.00%fcf_RedemptionPriceAsPercentageOfPrincipalAmount / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = fcf_FirstCommonwealthCapitalTrustTwoMember |  |
Deferred finance costs | 471,000us-gaap_DeferredFinanceCostsGross / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = fcf_FirstCommonwealthCapitalTrustTwoMember |  |
First Commonwealth Capital Trust I [Member] |  |  |
Subordinated Borrowing [Line Items] |  |  |
Deferred issuance costs |  | 500,000us-gaap_WriteOffOfDeferredDebtIssuanceCost / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = fcf_FirstCommonwealthCapitalTrustOneMember |
Debentures authorized for redemption percentage |  | 100.00%fcf_PercentageOfPrincipalAmountAuthorizedForRedemptionChange / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = fcf_FirstCommonwealthCapitalTrustOneMember |
Redemption price as percentage of principal amount |  | 103.325%fcf_RedemptionPriceAsPercentageOfPrincipalAmount / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = fcf_FirstCommonwealthCapitalTrustOneMember |
Deferred finance costs | 996,000us-gaap_DeferredFinanceCostsGross / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = fcf_FirstCommonwealthCapitalTrustOneMember |  |
Redemption Premium |  | $ 1,100,000fcf_PaymentofRedemptionPremium / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = fcf_FirstCommonwealthCapitalTrustOneMember |
Fixed interest rate |  | 9.50%us-gaap_SubordinatedBorrowingInterestRate / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = fcf_FirstCommonwealthCapitalTrustOneMember |
LIBOR [Member] | Subordinated Debt [Member] | First Commonwealth Capital Trust III [Member] |  |  |
Subordinated Borrowing [Line Items] |  |  |
Variable interest rate | 2.85%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1 / us-gaap_LongtermDebtTypeAxis = us-gaap_SubordinatedDebtMember / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = fcf_FirstCommonwealthCapitalTrustThreeMember / us-gaap_VariableRateAxis = us-gaap_LondonInterbankOfferedRateLIBORMember |  | 2.85%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1 / us-gaap_LongtermDebtTypeAxis = us-gaap_SubordinatedDebtMember / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = fcf_FirstCommonwealthCapitalTrustThreeMember / us-gaap_VariableRateAxis = us-gaap_LondonInterbankOfferedRateLIBORMember
LIBOR [Member] | Subordinated Debt [Member] | First Commonwealth Capital Trust II [Member] |  |  |
Subordinated Borrowing [Line Items] |  |  |
Variable interest rate | 2.85%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1 / us-gaap_LongtermDebtTypeAxis = us-gaap_SubordinatedDebtMember / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = fcf_FirstCommonwealthCapitalTrustTwoMember / us-gaap_VariableRateAxis = us-gaap_LondonInterbankOfferedRateLIBORMember |  | 2.85%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1 / us-gaap_LongtermDebtTypeAxis = us-gaap_SubordinatedDebtMember / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = fcf_FirstCommonwealthCapitalTrustTwoMember / us-gaap_VariableRateAxis = us-gaap_LondonInterbankOfferedRateLIBORMember

X
- Definition Payment of Redemption Premium + References No definition available. + Details
Name: | fcf_PaymentofRedemptionPremium
Namespace Prefix: | fcf_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Percentage Of Each Trust Common Equity Owned By Corporation + References No definition available. + Details
Name: | fcf_PercentageOfEachTrustCommonEquityOwnedByCorporation
Namespace Prefix: | fcf_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage of outstanding principal available to be redeemed. + References No definition available. + Details
Name: | fcf_PercentageOfPrincipalAmountAuthorizedForRedemptionChange
Namespace Prefix: | fcf_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Redemption Price As Percentage Of Principal Amount + References No definition available. + Details
Name: | fcf_RedemptionPriceAsPercentageOfPrincipalAmount
Namespace Prefix: | fcf_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage points added to the reference rate to compute the variable rate on the debt instrument. + References No definition available. + Details
Name: | us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- 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
Name: | us-gaap_DeferredFinanceCostsGross
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Stated interest rate of the subordinated debt. + References No definition available. + Details
Name: | us-gaap_SubordinatedBorrowingInterestRate
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_SubordinatedBorrowingLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Write-off of amounts previously capitalized as debt issuance cost in an extinguishment of debt. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.8) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 + Details
Name: | us-gaap_WriteOffOfDeferredDebtIssuanceCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=fcf_FirstCommonwealthCapitalTrustMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=fcf_FirstCommonwealthCapitalTrustOneMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=fcf_FirstCommonwealthCapitalTrustThreeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=fcf_FirstCommonwealthCapitalTrustTwoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |