XML 72 R69.htm IDEA: XBRL DOCUMENT
v3.20.1

Fair Values of Assets and Liabilities - Losses Realized on Assets Measured on Non-Recurring Basis (Detail) - USD ($) $ in Thousands | 3 Months Ended
--- | ---
Mar. 31, 2020 | Mar. 31, 2019
Fair Value Disclosures [Abstract] |  |
Impaired loans | $ (8,029) | $ (969)
Other real estate owned | (101) | (49)
Total losses | $ (8,130) | $ (1,018)

X
- Definition Net losses on assets measured on nonrecurring basis. + References No definition available. + Details
Name: | fcf_FairValueMeasurementOfAssetsOnNonrecurringBasisNetLoss
Namespace Prefix: | fcf_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Net losses on impaired loans still held at the end of the period. + References No definition available. + Details
Name: | fcf_FairValueMeasurementOfAssetsOnNonrecurringBasisNetLossesOnImpairedLoans
Namespace Prefix: | fcf_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Net losses on other real estate owned still held at the end of the period + References No definition available. + Details
Name: | fcf_FairValueMeasurementOfAssetsOnNonrecurringBasisNetLossesOnOtherRealEstateOwned
Namespace Prefix: | fcf_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_FairValueDisclosuresAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration