XML 96 R81.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Impairment of Investment Securities - Schedule of Unrealized Losses and Estimated Fair Values (Detail) - USD ($) $ in Thousands | Dec. 31, 2018 | Dec. 31, 2017
--- | --- | ---
Schedule Of Unrealized Losses On Securities [Line Items] |  |
Estimated Fair Value, Less Than 12 Months | $ 278,207 | $ 431,247
Available For Sale Securities Continuous Unrealized Income Loss Position Less Than Twelve Months Aggregate Gain Losses | (3,121) | (3,386)
Estimated Fair Value, 12 Months or More | 733,222 | 456,539
SecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses | (24,933) | (15,148)
Total Estimated Fair Value | 1,011,429 | 887,786
Total Gross Unrealized Losses | (28,054) | (18,534)
Corporate Securities [Member] |  |
Schedule Of Unrealized Losses On Securities [Line Items] |  |
Estimated Fair Value, Less Than 12 Months | 14,769 | 3,993
Available For Sale Securities Continuous Unrealized Income Loss Position Less Than Twelve Months Aggregate Gain Losses | (214) | (4)
Estimated Fair Value, 12 Months or More | 3,993 | 0
SecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses | (7) | 0
Total Estimated Fair Value | 18,762 | 3,993
Total Gross Unrealized Losses | (221) | (4)
Pooled Trust Preferred Collateralized Debt Obligations [Member] |  |
Schedule Of Unrealized Losses On Securities [Line Items] |  |
Estimated Fair Value, Less Than 12 Months |  | 0
Available For Sale Securities Continuous Unrealized Income Loss Position Less Than Twelve Months Aggregate Gain Losses |  | 0
Estimated Fair Value, 12 Months or More |  | 19,120
SecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses |  | (4,379)
Total Estimated Fair Value |  | 19,120
Total Gross Unrealized Losses |  | (4,379)
Obligations of U.S. Government [Member] | Mortgage - Backed Securities - Residential [Member] |  |
Schedule Of Unrealized Losses On Securities [Line Items] |  |
Estimated Fair Value, Less Than 12 Months | 2,289 | 5,584
Available For Sale Securities Continuous Unrealized Income Loss Position Less Than Twelve Months Aggregate Gain Losses | (41) | (21)
Estimated Fair Value, 12 Months or More | 5,028 | 0
SecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses | (140) | 0
Total Estimated Fair Value | 7,317 | 5,584
Total Gross Unrealized Losses | (181) | (21)
Obligations of U.S. Government [Member] | Mortgage - Backed Securities - Commercial [Member] |  |
Schedule Of Unrealized Losses On Securities [Line Items] |  |
Estimated Fair Value, Less Than 12 Months | 95,826 | 48,322
Available For Sale Securities Continuous Unrealized Income Loss Position Less Than Twelve Months Aggregate Gain Losses | (925) | (962)
Estimated Fair Value, 12 Months or More | 75,959 | 32,683
SecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses | (3,505) | (894)
Total Estimated Fair Value | 171,785 | 81,005
Total Gross Unrealized Losses | (4,430) | (1,856)
Obligations of U.S. Government-Sponsored Enterprises [Member] | Mortgage - Backed Securities - Residential [Member] |  |
Schedule Of Unrealized Losses On Securities [Line Items] |  |
Estimated Fair Value, Less Than 12 Months | 156,732 | 351,222
Available For Sale Securities Continuous Unrealized Income Loss Position Less Than Twelve Months Aggregate Gain Losses | (1,856) | (2,295)
Estimated Fair Value, 12 Months or More | 626,003 | 400,984
SecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses | (20,789) | (9,746)
Total Estimated Fair Value | 782,735 | 752,206
Total Gross Unrealized Losses | (22,645) | (12,041)
Obligations of U.S. Government-Sponsored Enterprises [Member] | Mortgage - Backed Securities - Commercial [Member] |  |
Schedule Of Unrealized Losses On Securities [Line Items] |  |
Estimated Fair Value, Less Than 12 Months | 0 | 13,985
Available For Sale Securities Continuous Unrealized Income Loss Position Less Than Twelve Months Aggregate Gain Losses | 0 | (71)
Estimated Fair Value, 12 Months or More | 12,901 | 0
SecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses | (258) | 0
Total Estimated Fair Value | 12,901 | 13,985
Total Gross Unrealized Losses | (258) | (71)
Obligations of U.S. Government-Sponsored Enterprises [Member] | Other Government - Sponsored Enterprises [Member] |  |
Schedule Of Unrealized Losses On Securities [Line Items] |  |
Estimated Fair Value, Less Than 12 Months |  | 997
Available For Sale Securities Continuous Unrealized Income Loss Position Less Than Twelve Months Aggregate Gain Losses |  | (1)
Estimated Fair Value, 12 Months or More |  | 99
SecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses |  | 0
Total Estimated Fair Value |  | 1,096
Total Gross Unrealized Losses |  | (1)
US States and Political Subdivisions Debt Securities [Member] | Other Government - Sponsored Enterprises [Member] |  |
Schedule Of Unrealized Losses On Securities [Line Items] |  |
Estimated Fair Value, Less Than 12 Months | 8,591 | 7,144
Available For Sale Securities Continuous Unrealized Income Loss Position Less Than Twelve Months Aggregate Gain Losses | (85) | (32)
Estimated Fair Value, 12 Months or More | 9,338 | 3,653
SecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses | (234) | (129)
Total Estimated Fair Value | 17,929 | 10,797
Total Gross Unrealized Losses | $ (319) | $ (161)

X
- Definition Schedule Of Unrealized Losses On Securities [Line Items] + References No definition available. + Details
Name: | fcf_ScheduleOfUnrealizedLossesOnSecuritiesLineItems
Namespace Prefix: | fcf_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition SecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses + References No definition available. + Details
Name: | fcf_SecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses
Namespace Prefix: | fcf_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition SecuritiesContinuousUnrealizedLossPositionAggregateLosses + References No definition available. + Details
Name: | fcf_SecuritiesContinuousUnrealizedLossPositionAggregateLosses
Namespace Prefix: | fcf_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Securities Continuous Unrealized Loss Position Fair Value + References No definition available. + Details
Name: | fcf_SecuritiesContinuousUnrealizedLossPositionFairValue
Namespace Prefix: | fcf_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Securities, Continuous Unrealized Loss Position Less Than 12 Months Aggregate Losses + References No definition available. + Details
Name: | fcf_SecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLosses
Namespace Prefix: | fcf_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value + References No definition available. + Details
Name: | fcf_SecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
Namespace Prefix: | fcf_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Securities Continuous Unrealized Loss Position Twelve Months or Longer Fair Value + References No definition available. + Details
Name: | fcf_SecuritiesContinuousUnrealizedLossPositionTwelveMonthsorLongerFairValue
Namespace Prefix: | fcf_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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

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

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_USTreasuryAndGovernmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

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

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

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_USStatesAndPoliticalSubdivisionsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |