XML 91 R81.htm IDEA: XBRL DOCUMENT
v3.23.3

Revenue Recognition Revenue Recognition (Details) - USD ($) $ in Millions | 9 Months Ended
--- | ---
Sep. 30, 2023 | Sep. 30, 2022
Additional Information [Abstract] |  |
Management Fees, Incentive Revenue (Deprecated 2018-01-31) | $ 0.3 |
Brokerage Commissions Revenue | $ 3.1 | $ 2.9

X
- Definition Additional Information [Abstract] + References No definition available. + Details
Name: | fcf_AdditionalInformationAbstract
Namespace Prefix: | fcf_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Incentive Revenue + References No definition available. + Details
Name: | fcf_IncentiveRevenue
Namespace Prefix: | fcf_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of commission revenue from buying and selling securities on behalf of customers. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 940 -SubTopic 20 -Section 05 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481996/940-20-05-3 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 942 -SubTopic 220 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04.13(a),(b)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147483589/942-220-S99-1 + Details
Name: | us-gaap_BrokerageCommissionsRevenue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration