XML 83 R72.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Fair Values of Assets and Liabilities - Losses Realized on Assets Measured on Non-Recurring Basis (Detail) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2018 | Jun. 30, 2017 | Jun. 30, 2018 | Jun. 30, 2017
Fair Value Disclosures [Abstract] |  |  |  |
Impaired loans | $ 992 | $ (238) | $ (6,544) | $ (1,278)
Other real estate owned | (437) | (1,094) | (437) | (1,125)
Total losses | $ 555 | $ (1,332) | $ (6,981) | $ (2,403)

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