XML 60 R82.htm IDEA: XBRL DOCUMENT
v3.19.3.a.u2

Impairment of Investment Securities - Schedule of Unrealized Losses and Estimated Fair Values (Detail) - USD ($) $ in Thousands | Dec. 31, 2019 | Dec. 31, 2018
--- | --- | ---
Schedule Of Unrealized Losses On Securities [Line Items] |  |
Estimated Fair Value, Less Than 12 Months | $ 166,470 | $ 278,207
Available For Sale Securities Continuous Unrealized Income Loss Position Less Than Twelve Months Aggregate Gain Losses | (637) | (3,121)
Estimated Fair Value, 12 Months or More | 235,380 | 733,222
SecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses | (2,950) | (24,933)
Total Estimated Fair Value | 401,850 | 1,011,429
Total Gross Unrealized Losses | (3,587) | (28,054)
Corporate Securities [Member] |  |
Schedule Of Unrealized Losses On Securities [Line Items] |  |
Estimated Fair Value, Less Than 12 Months |  | 14,769
Available For Sale Securities Continuous Unrealized Income Loss Position Less Than Twelve Months Aggregate Gain Losses |  | (214)
Estimated Fair Value, 12 Months or More |  | 3,993
SecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses |  | (7)
Total Estimated Fair Value |  | 18,762
Total Gross Unrealized Losses |  | (221)
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
Available For Sale Securities Continuous Unrealized Income Loss Position Less Than Twelve Months Aggregate Gain Losses |  | (41)
Estimated Fair Value, 12 Months or More |  | 5,028
SecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses |  | (140)
Total Estimated Fair Value |  | 7,317
Total Gross Unrealized Losses |  | (181)
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 | 54,501 | 95,826
Available For Sale Securities Continuous Unrealized Income Loss Position Less Than Twelve Months Aggregate Gain Losses | (201) | (925)
Estimated Fair Value, 12 Months or More | 16,365 | 75,959
SecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses | (149) | (3,505)
Total Estimated Fair Value | 70,866 | 171,785
Total Gross Unrealized Losses | (350) | (4,430)
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 | 111,969 | 156,732
Available For Sale Securities Continuous Unrealized Income Loss Position Less Than Twelve Months Aggregate Gain Losses | (436) | (1,856)
Estimated Fair Value, 12 Months or More | 219,015 | 626,003
SecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses | (2,801) | (20,789)
Total Estimated Fair Value | 330,984 | 782,735
Total Gross Unrealized Losses | $ (3,237) | (22,645)
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
Available For Sale Securities Continuous Unrealized Income Loss Position Less Than Twelve Months Aggregate Gain Losses |  | 0
Estimated Fair Value, 12 Months or More |  | 12,901
SecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses |  | (258)
Total Estimated Fair Value |  | 12,901
Total Gross Unrealized Losses |  | (258)
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
Available For Sale Securities Continuous Unrealized Income Loss Position Less Than Twelve Months Aggregate Gain Losses |  | (85)
Estimated Fair Value, 12 Months or More |  | 9,338
SecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses |  | (234)
Total Estimated Fair Value |  | 17,929
Total Gross Unrealized Losses |  | $ (319)

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_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_FinancialInstrumentAxis=us-gaap_USStatesAndPoliticalSubdivisionsMember
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: |