XML 61 R48.htm IDEA: XBRL DOCUMENT
v3.7.0.1

Impairment of Investment Securities - Additional Information (Detail) | 3 Months Ended |
--- | --- | ---
Mar. 31, 2017 USD ($) Security Bank | Mar. 31, 2016 USD ($) | Dec. 31, 2016 USD ($)
Schedule of Trading Securities and Other Trading Assets [Line Items] |  |  |
Other than temporary impairment charges recognized | $ 0 | $ 0 |
Amortized Cost | 842,333,000 |  | $ 790,082,000
Securities available for sale, at fair value | $ 832,754,000 |  | 778,612,000
Number of banks and other financial institutions comprising the security | Bank | 257 |  |
Number Of Pooled Securities with No Senior Class | Security | 2 |  |
Number of securities with no excess subordination | Security | 2 |  |
Number of Securities with Excess Subordination | Security | 6 |  |
Coupon rate | 7.00% |  |
Probability of default | 100.00% |  |
Projected recovery rate | 0.00% |  |
Probability percentage assigned to default bank subject to market indicators | 10.00% |  |
Probability percentage assigned to default bank | 100.00% |  |
Federal Home Loan Bank Stock | $ 38,669,000 |  | 36,498,000
Investment Securities in Unrealized Loss Position, Qualitative Disclosure, Number of Positions, Total | 116 |  |
Minimum [Member] |  |  |
Schedule of Trading Securities and Other Trading Assets [Line Items] |  |  |
Subordinated tranches range | 7.00% |  |
Total principal amount of the respective securities | 5.00% |  |
Excess subordination as a percentage of current performing collateral | 2.00% |  |
Probabilities for performing collateral range | 0.33% |  |
Excess present value of future cash flows over our current book value | 19.00% |  |
Maximum [Member] |  |  |
Schedule of Trading Securities and Other Trading Assets [Line Items] |  |  |
Subordinated tranches range | 35.00% |  |
Excess subordination as a percentage of current performing collateral | 85.00% |  |
Probabilities for performing collateral range | 75.00% |  |
Excess present value of future cash flows over our current book value | 115.00% |  |
Pooled Trust Preferred Collateralized Debt Obligations [Member] |  |  |
Schedule of Trading Securities and Other Trading Assets [Line Items] |  |  |
Percent of Unrealized Losses | 34.00% |  |
Securities available for sale, at fair value | $ 33,741,000 |  | 33,292,000
Trust preferred collateralized debt obligations [Member] |  |  |
Schedule of Trading Securities and Other Trading Assets [Line Items] |  |  |
Other than temporary impairment charges recognized | $ 0 | 0 |
Percentage of Current Performing Collateral | 0.00% |  |
Corporate Debt Securities [Member] |  |  |
Schedule of Trading Securities and Other Trading Assets [Line Items] |  |  |
Securities available for sale, at fair value | $ 16,369,000 |  | 6,319,000
Pooled Trust Preferred Securities [Member] |  |  |
Schedule of Trading Securities and Other Trading Assets [Line Items] |  |  |
Other than temporary impairment charges recognized | 0 | 0 |
Equity Securities [Member] |  |  |
Schedule of Trading Securities and Other Trading Assets [Line Items] |  |  |
Other than temporary impairment charges recognized | 0 | $ 0 |
Continuous Unrealized Loss Position, Fair Value | 0 |  | 0
Asset Size and Coupon Rate 1 [Member] |  |  |
Schedule of Trading Securities and Other Trading Assets [Line Items] |  |  |
Collateral issued by financial institutions | $ 15,000,000,000 |  |
Coupon rate | 7.00% |  |
Prepayment rate | 100.00% |  |
Asset Size and Coupon Rate 2 [Member] |  |  |
Schedule of Trading Securities and Other Trading Assets [Line Items] |  |  |
Coupon rate | 7.00% |  |
Fair Value Inputs , Prepayment Rate Year One and Two | 40.00% |  |
Fair Value Inputs , Prepayment Rate After Year Two | 2.00% |  |
Asset Size and Coupon Rate 3 [Member] |  |  |
Schedule of Trading Securities and Other Trading Assets [Line Items] |  |  |
Prepayment rate | 5.00% |  |
Asset Size and Coupon Rate 3 [Member] | Minimum [Member] |  |  |
Schedule of Trading Securities and Other Trading Assets [Line Items] |  |  |
Collateral issued by financial institutions | $ 2,000,000,000 |  |
Asset Size and Coupon Rate 3 [Member] | Maximum [Member] |  |  |
Schedule of Trading Securities and Other Trading Assets [Line Items] |  |  |
Collateral issued by financial institutions | 15,000,000,000 |  |
Asset Size and Coupon Rate 4 [Member] |  |  |
Schedule of Trading Securities and Other Trading Assets [Line Items] |  |  |
Collateral issued by financial institutions | $ 2,000,000,000 |  |
Coupon rate | 10.00% |  |
Prepayment rate | 5.00% |  |
Asset Size and Coupon Rate 5 [Member] |  |  |
Schedule of Trading Securities and Other Trading Assets [Line Items] |  |  |
Prepayment rate | 0.00% |  |
Obligations of U.S. Government-Sponsored Enterprises - Other Government-Sponsored Enterprises [Member] |  |  |
Schedule of Trading Securities and Other Trading Assets [Line Items] |  |  |
Percent of Unrealized Losses | 60.00% |  |
Reported Value Measurement [Member] |  |  |
Schedule of Trading Securities and Other Trading Assets [Line Items] |  |  |
Securities available for sale, at fair value | $ 832,754,000 |  | $ 778,612,000
Federal Home Loan Bank Stock | $ 38,669,000 |  |

X
- Definition Available-for-sale, securities in unrealized loss, percentage. + References No definition available. + Details
Name: | fcf_AvailableForSaleSecuritiesInUnrealizedLossPercentage
Namespace Prefix: | fcf_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Excess present value of future cash flows over our current book value. + References No definition available. + Details
Name: | fcf_ExcessPresentValueOfFutureCashFlowsOverOurCurrentBookValue
Namespace Prefix: | fcf_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Excess subordination as a percentage of current performing collateral. + References No definition available. + Details
Name: | fcf_ExcessSubordinationAsPercentageOfCurrentPerformingCollateral
Namespace Prefix: | fcf_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Fair Value Inputs, Collateral + References No definition available. + Details
Name: | fcf_FairValueInputsCollateral
Namespace Prefix: | fcf_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair Value Inputs, Coupon Rate + References No definition available. + Details
Name: | fcf_FairValueInputsCouponRate
Namespace Prefix: | fcf_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Fair Value Inputs , Prepayment Rate After Year Two + References No definition available. + Details
Name: | fcf_FairValueInputsPrepaymentRateAfterYearTwo
Namespace Prefix: | fcf_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Fair Value Inputs , Prepayment Rate Year One and Two + References No definition available. + Details
Name: | fcf_FairValueInputsPrepaymentRateYearOneAndTwo
Namespace Prefix: | fcf_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Investment Securities in Unrealized Loss Position, Qualitative Disclosure, Number of Positions, Total + References No definition available. + Details
Name: | fcf_InvestmentSecuritiesinUnrealizedLossPositionQualitativeDisclosureNumberofPositionsTotal
Namespace Prefix: | fcf_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of banks and other financial institutions comprising the security. + References No definition available. + Details
Name: | fcf_NumberOfBanksAndOtherFinancialInstitutionsComprisingSecurity
Namespace Prefix: | fcf_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number Of Pooled Securities with No Senior Class + References No definition available. + Details
Name: | fcf_NumberOfPooledSecuritiesWithNoSeniorClass
Namespace Prefix: | fcf_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of Securities with Excess Subordination + References No definition available. + Details
Name: | fcf_NumberOfSecuritiesWithExcessSubordination
Namespace Prefix: | fcf_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of Securities with No Excess Subordination + References No definition available. + Details
Name: | fcf_NumberOfSecuritiesWithNoExcessSubordination
Namespace Prefix: | fcf_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percent of Unrealized Losses + References No definition available. + Details
Name: | fcf_PercentOfUnrealizedLosses
Namespace Prefix: | fcf_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage of principal amount in pooled security securities. + References No definition available. + Details
Name: | fcf_PercentageOfPrincipalAmountInPooledSecuritySecurities
Namespace Prefix: | fcf_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Probabilities for performing collateral range. + References No definition available. + Details
Name: | fcf_ProbabilitiesForPerformingCollateralRange
Namespace Prefix: | fcf_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Probability of default. + References No definition available. + Details
Name: | fcf_ProbabilityOfDefault
Namespace Prefix: | fcf_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Probability percentage assigned to default bank. + References No definition available. + Details
Name: | fcf_ProbabilityPercentageAssignedToDefaultBank
Namespace Prefix: | fcf_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Probability percentage assigned to default bank subject to market indicators. + References No definition available. + Details
Name: | fcf_ProbabilityPercentageAssignedToDefaultBankSubjectToMarketIndicators
Namespace Prefix: | fcf_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Projected recovery rate. + References No definition available. + Details
Name: | fcf_ProjectedRecoveryRate
Namespace Prefix: | fcf_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Subordinated tranches range. + References No definition available. + Details
Name: | fcf_SubordinatedTranchesRange
Namespace Prefix: | fcf_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 25 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=65884222&loc=d3e22054-111558 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=66010992&loc=d3e26610-111562 + Details
Name: | us-gaap_AvailableForSaleSecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.2) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_AvailableForSaleSecuritiesAmortizedCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This item represents the aggregate fair value of investments in debt and equity securities in an unrealized loss position which are categorized neither as held-to-maturity nor trading securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27290-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Rate at which loans or a loan portfolio are expected to prepay principal balances, used as an input to measure fair value. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (bbb) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueInputsPrepaymentRate
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Federal Home Loan Bank (FHLB) stock represents an equity interest in a FHLB. It does not have a readily determinable fair value because its ownership is restricted and it lacks a market (liquidity). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 325 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6478792&loc=d3e63345-112809 + Details
Name: | us-gaap_FederalHomeLoanBankStock
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The amount of other than temporary impairment (OTTI) losses on equity securities, OTTI related to credit losses on debt securities, and OTTI losses on debt securities when the entity intends to sell the securities or it is more likely than not that the entity will be required to sell the securities before recovery of its amortized cost basis. Additionally, this item includes OTTI losses recognized during the period on investments accounted for under the cost method of accounting. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 8B -URI http://asc.fasb.org/extlink&oid=73527792&loc=SL6284393-111563 + Details
Name: | us-gaap_OtherThanTemporaryImpairmentLossesInvestmentsPortionRecognizedInEarningsNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_TrustPreferredSecuritiesSubjectToMandatoryRedemptionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=fcf_TrustPreferredCollateralizedDebtObligationsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=fcf_PooledTrustPreferredSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_EquitySecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | fcf_EstimateOfFutureCashFlowAxis=fcf_AssetSizeAndCouponRate1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | fcf_EstimateOfFutureCashFlowAxis=fcf_AssetSizeAndCouponRate2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | fcf_EstimateOfFutureCashFlowAxis=fcf_AssetSizeAndCouponRate3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | fcf_EstimateOfFutureCashFlowAxis=fcf_AssetSizeAndCouponRate4Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | fcf_EstimateOfFutureCashFlowAxis=fcf_AssetSizeAndCouponRate5Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByLiabilityClassAxis=us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByMeasurementBasisAxis=us-gaap_CarryingReportedAmountFairValueDisclosureMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |