XML 64 R50.htm IDEA: XBRL DOCUMENT
v3.5.0.2

Impairment of Investment Securities - Pooled Trust Preferred Collateralized Debt Obligations (Detail) $ in Thousands | 9 Months Ended |
--- | --- | ---
Sep. 30, 2016 USD ($) Bank | Dec. 31, 2015 USD ($)
Impairment Of Investment Securities [Line Items] |  |
Securities available for sale, at fair value | $ 813,659 | $ 886,560
Unrealized Gain (Loss) | 8,644 | $ 16,477
Pooled Trust Preferred Collateralized Debt Obligations [Member] |  |
Impairment Of Investment Securities [Line Items] |  |
Book Value | 43,020 |
Securities available for sale, at fair value | 35,609 |
Unrealized Gain (Loss) | (7,411) |
Pooled Trust Preferred Collateralized Debt Obligations [Member] | Mezzanine [Member] | Pre TSL IV [Member] |  |
Impairment Of Investment Securities [Line Items] |  |
Book Value | 1,830 |
Securities available for sale, at fair value | 1,331 |
Unrealized Gain (Loss) | $ (499) |
Debt Instrument, Credit Rating | B1/BB |
Number of Banks (in banks) | Bank | 6 |
Deferrals and Defaults as a % of Current Collateral | 18.05% |
Excess Subordination as a % of Current Performing Collateral | 60.61% |
Pooled Trust Preferred Collateralized Debt Obligations [Member] | Mezzanine [Member] | Pre TSL VII [Member] |  |
Impairment Of Investment Securities [Line Items] |  |
Book Value | $ 3,119 |
Securities available for sale, at fair value | 3,513 |
Unrealized Gain (Loss) | $ 394 |
Debt Instrument, Credit Rating | Ca/- |
Number of Banks (in banks) | Bank | 14 |
Deferrals and Defaults as a % of Current Collateral | 47.77% |
Excess Subordination as a % of Current Performing Collateral | 0.00% |
Pooled Trust Preferred Collateralized Debt Obligations [Member] | Mezzanine [Member] | Pre TSL VIII [Member] |  |
Impairment Of Investment Securities [Line Items] |  |
Book Value | $ 2,063 |
Securities available for sale, at fair value | 2,025 |
Unrealized Gain (Loss) | $ (38) |
Debt Instrument, Credit Rating | C/C |
Number of Banks (in banks) | Bank | 28 |
Deferrals and Defaults as a % of Current Collateral | 44.37% |
Excess Subordination as a % of Current Performing Collateral | 0.00% |
Pooled Trust Preferred Collateralized Debt Obligations [Member] | Mezzanine [Member] | Pre TSL IX [Member] |  |
Impairment Of Investment Securities [Line Items] |  |
Book Value | $ 2,403 |
Securities available for sale, at fair value | 1,893 |
Unrealized Gain (Loss) | $ (510) |
Debt Instrument, Credit Rating | B1/C |
Number of Banks (in banks) | Bank | 37 |
Deferrals and Defaults as a % of Current Collateral | 27.83% |
Excess Subordination as a % of Current Performing Collateral | 12.79% |
Pooled Trust Preferred Collateralized Debt Obligations [Member] | Mezzanine [Member] | Pre TSL X [Member] |  |
Impairment Of Investment Securities [Line Items] |  |
Book Value | $ 1,707 |
Securities available for sale, at fair value | 1,887 |
Unrealized Gain (Loss) | $ 180 |
Debt Instrument, Credit Rating | Caa1/C |
Number of Banks (in banks) | Bank | 42 |
Deferrals and Defaults as a % of Current Collateral | 31.58% |
Excess Subordination as a % of Current Performing Collateral | 2.17% |
Pooled Trust Preferred Collateralized Debt Obligations [Member] | Mezzanine [Member] | Pre TSL XII [Member] |  |
Impairment Of Investment Securities [Line Items] |  |
Book Value | $ 5,839 |
Securities available for sale, at fair value | 4,584 |
Unrealized Gain (Loss) | $ (1,255) |
Debt Instrument, Credit Rating | B3/C |
Number of Banks (in banks) | Bank | 64 |
Deferrals and Defaults as a % of Current Collateral | 24.50% |
Excess Subordination as a % of Current Performing Collateral | 0.00% |
Pooled Trust Preferred Collateralized Debt Obligations [Member] | Mezzanine [Member] | Pre TSL XIII [Member] |  |
Impairment Of Investment Securities [Line Items] |  |
Book Value | $ 12,888 |
Securities available for sale, at fair value | 10,504 |
Unrealized Gain (Loss) | $ (2,384) |
Debt Instrument, Credit Rating | Ba3/C |
Number of Banks (in banks) | Bank | 54 |
Deferrals and Defaults as a % of Current Collateral | 11.75% |
Excess Subordination as a % of Current Performing Collateral | 48.41% |
Pooled Trust Preferred Collateralized Debt Obligations [Member] | Mezzanine [Member] | Pre TSL XIV [Member] |  |
Impairment Of Investment Securities [Line Items] |  |
Book Value | $ 12,960 |
Securities available for sale, at fair value | 9,559 |
Unrealized Gain (Loss) | $ (3,401) |
Debt Instrument, Credit Rating | B1/CC |
Number of Banks (in banks) | Bank | 54 |
Deferrals and Defaults as a % of Current Collateral | 13.45% |
Excess Subordination as a % of Current Performing Collateral | 37.92% |
Pooled Trust Preferred Collateralized Debt Obligations [Member] | Mezzanine [Member] | MMCap I [Member] |  |
Impairment Of Investment Securities [Line Items] |  |
Book Value | $ 211 |
Securities available for sale, at fair value | 313 |
Unrealized Gain (Loss) | $ 102 |
Debt Instrument, Credit Rating | Ca/C |
Number of Banks (in banks) | Bank | 8 |
Deferrals and Defaults as a % of Current Collateral | 58.11% |
Excess Subordination as a % of Current Performing Collateral | 81.65% |

X
- Definition Available for sale securities book value. + References No definition available. + Details
Name: | fcf_AvailableForSaleSecuritiesBookValue
Namespace Prefix: | fcf_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Deferrals and defaults as a percentage of current collateral. + References No definition available. + Details
Name: | fcf_DeferralsAndDefaultsAsPercentageOfCurrentCollateral
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 Impairment Of Investment Securities [Line Items] + References No definition available. + Details
Name: | fcf_ImpairmentOfInvestmentSecuritiesLineItems
Namespace Prefix: | fcf_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Pooled trust preferred collateralized debt obligations in number of banks. + References No definition available. + Details
Name: | fcf_PooledTrustPreferredCollateralizedDebtObligationsInNumberOfBanks
Namespace Prefix: | fcf_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt securities classified as available-for-sale. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27161-111563 + Details
Name: | us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
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=51813488&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=27724398&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=49167202&loc=d3e26610-111562 + Details
Name: | us-gaap_AvailableForSaleSecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Description of the credit rating indicative of likelihood of repayment of the debt instrument given by a credit rating agency (for example, Standard and Poor's, Moody's, Fitch). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 + Details
Name: | us-gaap_DebtInstrumentCreditRating
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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

X
- Details
Name: | us-gaap_EligibleItemOrGroupForFairValueOptionAxis=fcf_MezzanineMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

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

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

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

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

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

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

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