XML 52 R137.htm IDEA: XBRL DOCUMENT
v3.19.3.a.u2

Regulatory Restrictions and Capital Adequacy - Schedule of Capital Amount and Ratio Considered to be Capitalized (Detail) - USD ($) $ in Thousands | Dec. 31, 2019 | Dec. 31, 2018
--- | --- | ---
First Commonwealth Financial Corporation |  |
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] |  |
Tier 1 Common Equity to Risk Weighted Assets | $ 730,526 | $ 697,881
Tier 1 Common Equity to Risk Weighted Assets | 10.91% | 11.13%
Tier 1 Common Equity Required to be Well Capitalized | $ 435,420 | $ 407,557
Tier 1 Common Equity Required to be Well Capitalized to Risk Weighted Assets | 6.50% | 6.50%
First Commonwealth Bank |  |
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] |  |
Tier 1 Common Equity to Risk Weighted Assets | $ 759,398 | $ 734,246
Tier 1 Common Equity to Risk Weighted Assets | 11.36% | 11.73%
Tier 1 Common Equity Required to be Well Capitalized | $ 434,575 | $ 406,925
Tier 1 Common Equity Required to be Well Capitalized to Risk Weighted Assets | 6.50% | 6.50%
Actual | First Commonwealth Financial Corporation |  |
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] |  |
Total Capital to Risk Weighted Assets | $ 954,991 | $ 918,786
Tier I Capital to Risk Weighted Assets | 800,526 | 767,881
Tier I Capital to Average Assets | $ 800,526 | $ 767,881
Total Capital to Risk Weighted Assets, Ratio | 14.26% | 14.65%
Tier I Capital to Risk Weighted Assets, Ratio | 11.95% | 12.25%
Tier I Capital to Average Assets, Ratio | 10.17% | 10.28%
Actual | First Commonwealth Bank |  |
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] |  |
Total Capital to Risk Weighted Assets | $ 913,863 | $ 885,151
Tier I Capital to Risk Weighted Assets | 759,398 | 734,246
Tier I Capital to Average Assets | $ 759,398 | $ 734,246
Total Capital to Risk Weighted Assets, Ratio | 13.67% | 14.14%
Tier I Capital to Risk Weighted Assets, Ratio | 11.36% | 11.73%
Tier I Capital to Average Assets, Ratio | 9.66% | 9.84%
Minimum Capital Required - Basel III Phase-In Schedule | First Commonwealth Financial Corporation |  |
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] |  |
Total Capital to Risk Weighted Assets, Regulatory Minimum Capital Amount |  | $ 619,173
Tier I Capital to Risk Weighted Assets, Regulatory Minimum Capital Amount |  | 493,771
Tier I Capital to Average Assets, Regulatory Minimum Capital Amount |  | 298,856
Tier 1 Common Equity Required for Capital Adequacy |  | $ 399,719
Total Capital to Risk Weighted Assets, Regulatory Minimum Ratio |  | 9.88%
Tier I Capital to Risk Weighted Assets, Regulatory Minimum Ratio |  | 7.88%
Tier I Capital to Average Assets, Regulatory Minimum Ratio |  | 4.00%
Tier 1 Common Equity Required for Capital Adequacy to Risk Weighted Assets |  | 6.38%
Minimum Capital Required - Basel III Phase-In Schedule | First Commonwealth Bank |  |
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] |  |
Total Capital to Risk Weighted Assets, Regulatory Minimum Capital Amount |  | $ 618,213
Tier I Capital to Risk Weighted Assets, Regulatory Minimum Capital Amount |  | 493,005
Tier I Capital to Average Assets, Regulatory Minimum Capital Amount |  | 298,340
Tier 1 Common Equity Required for Capital Adequacy |  | $ 399,100
Total Capital to Risk Weighted Assets, Regulatory Minimum Ratio |  | 9.88%
Tier I Capital to Risk Weighted Assets, Regulatory Minimum Ratio |  | 7.88%
Tier I Capital to Average Assets, Regulatory Minimum Ratio |  | 4.00%
Tier 1 Common Equity Required for Capital Adequacy to Risk Weighted Assets |  | 6.38%
Minimum Capital Required | First Commonwealth Financial Corporation |  |
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] |  |
Total Capital to Risk Weighted Assets, Regulatory Minimum Capital Amount | $ 703,370 | $ 658,361
Tier I Capital to Risk Weighted Assets, Regulatory Minimum Capital Amount | 569,395 | 532,959
Tier I Capital to Average Assets, Regulatory Minimum Capital Amount | 314,963 | 298,856
Tier 1 Common Equity Required for Capital Adequacy | $ 468,914 | $ 438,907
Total Capital to Risk Weighted Assets, Regulatory Minimum Ratio | 10.50% | 10.50%
Tier I Capital to Risk Weighted Assets, Regulatory Minimum Ratio | 8.50% | 8.50%
Tier I Capital to Average Assets, Regulatory Minimum Ratio | 4.00% | 4.00%
Tier 1 Common Equity Required for Capital Adequacy to Risk Weighted Assets | 7.00% | 7.00%
Minimum Capital Required | First Commonwealth Bank |  |
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] |  |
Total Capital to Risk Weighted Assets, Regulatory Minimum Capital Amount | $ 702,006 | $ 657,341
Tier I Capital to Risk Weighted Assets, Regulatory Minimum Capital Amount | 568,291 | 532,133
Tier I Capital to Average Assets, Regulatory Minimum Capital Amount | 314,338 | 298,340
Tier 1 Common Equity Required for Capital Adequacy | $ 468,004 | $ 438,227
Total Capital to Risk Weighted Assets, Regulatory Minimum Ratio | 10.50% | 10.50%
Tier I Capital to Risk Weighted Assets, Regulatory Minimum Ratio | 8.50% | 8.50%
Tier I Capital to Average Assets, Regulatory Minimum Ratio | 4.00% | 4.00%
Tier 1 Common Equity Required for Capital Adequacy to Risk Weighted Assets | 7.00% | 7.00%
Required to be Considered Well Capitalized | First Commonwealth Financial Corporation |  |
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] |  |
Tier One Risk Based Capital Required to be Well Capitalized | $ 535,901 | $ 501,608
Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets | 8.00% | 8.00%
Tier One Leverage Capital Required to be Well Capitalized | $ 393,704 | $ 373,570
Tier One Leverage Capital Required to be Well Capitalized to Average Assets | 5.00% | 5.00%
Total Capital to Risk Weighted Assets, Well Capitalized Regulatory Guidelines | $ 669,877 | $ 627,011
Total Capital to Risk Weighted Assets, Well Capitalized Regulatory Guidelines | 10.00% | 10.00%
Required to be Considered Well Capitalized | First Commonwealth Bank |  |
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] |  |
Tier One Risk Based Capital Required to be Well Capitalized | $ 534,862 | $ 500,831
Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets | 8.00% | 8.00%
Tier One Leverage Capital Required to be Well Capitalized | $ 392,922 | $ 372,926
Tier One Leverage Capital Required to be Well Capitalized to Average Assets | 5.00% | 5.00%
Total Capital to Risk Weighted Assets, Well Capitalized Regulatory Guidelines | $ 668,577 | $ 626,039
Total Capital to Risk Weighted Assets, Well Capitalized Regulatory Guidelines | 10.00% | 10.00%

X
- Definition Tier One Common Equity + References No definition available. + Details
Name: | fcf_TierOneCommonEquity
Namespace Prefix: | fcf_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Tier One Common Equity Required for Capital Adequacy + References No definition available. + Details
Name: | fcf_TierOneCommonEquityRequiredforCapitalAdequacy
Namespace Prefix: | fcf_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Tier One Common Equity Required for Capital Adequacy to Risk Weighted Assets + References No definition available. + Details
Name: | fcf_TierOneCommonEquityRequiredforCapitalAdequacytoRiskWeightedAssets
Namespace Prefix: | fcf_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Tier One Common Equity Required to be Well Capitalized + References No definition available. + Details
Name: | fcf_TierOneCommonEquityRequiredtobeWellCapitalized
Namespace Prefix: | fcf_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Tier One Common Equity Required to be Well Capitalized to Risk Weighted Assets + References No definition available. + Details
Name: | fcf_TierOneCommonEquityRequiredtobeWellCapitalizedtoRiskWeightedAssets
Namespace Prefix: | fcf_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Tier One Common Equity to Risk Weighted Assets + References No definition available. + Details
Name: | fcf_TierOneCommonEquitytoRiskWeightedAssets
Namespace Prefix: | fcf_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The amount of total capital as defined in the regulations. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 948 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6490092&loc=d3e47304-110998 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1H -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=d3e65071-112826 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 948 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=6490092&loc=d3e47080-110998 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1H -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=117337116&loc=d3e65071-112826 + Details
Name: | us-gaap_Capital
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The minimum amount of Total Capital required for capital adequacy purposes under the regulatory framework for prompt corrective action. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1H -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=117337116&loc=d3e65071-112826 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_CapitalRequiredForCapitalAdequacy
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The minimum Total risk based capital ratio (total capital divided by risk weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958570-112826 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1H -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=117337116&loc=d3e65071-112826 + Details
Name: | us-gaap_CapitalRequiredForCapitalAdequacyToRiskWeightedAssets
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The amount of Total Capital required to be categorized as well as capitalized under the regulatory framework for prompt corrective action. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_CapitalRequiredToBeWellCapitalized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The Total risk based capital ratio (total capital divided by risk weighted assets) required to be categorized as "well capitalized", in the regulatory framework for prompt corrective action. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_CapitalRequiredToBeWellCapitalizedToRiskWeightedAssets
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Total Capital divided by risk weighted assets as defined in the regulations. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1H -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=117337116&loc=d3e65071-112826 + Details
Name: | us-gaap_CapitalToRiskWeightedAssets
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tier 1 Leverage Capital as defined in the regulations. Also called Core Capital. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1H -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=117337116&loc=d3e65071-112826 + Details
Name: | us-gaap_TierOneLeverageCapital
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The minimum amount of Tier 1 Leverage Capital required for capital adequacy purposes under the regulatory framework for prompt corrective action. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1H -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=117337116&loc=d3e65071-112826 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacy
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The minimum amount of Tier 1 Leverage Capital for capital adequacy purposes divided by average assets as defined in the regulations. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1H -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=117337116&loc=d3e65071-112826 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958570-112826 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The amount of Tier 1 Leverage Capital required to be categorized as well capitalized under the regulatory framework for prompt corrective action. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The amount of Tier 1 Leverage Capital required to be categorized as well capitalized divided by average assets as defined in the regulatory framework for prompt corrective action. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalizedToAverageAssets
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Tier 1 Leverage Capital divided by average assets as defined in the regulations. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1H -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=117337116&loc=d3e65071-112826 + Details
Name: | us-gaap_TierOneLeverageCapitalToAverageAssets
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Tier 1 Risk Based Capital as defined in the regulations. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1H -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=117337116&loc=d3e65071-112826 + Details
Name: | us-gaap_TierOneRiskBasedCapital
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The minimum amount of Tier 1 Risk Based Capital required for capital adequacy purposes under the regulatory framework for prompt corrective action. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1H -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=117337116&loc=d3e65071-112826 + Details
Name: | us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacy
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The minimum Tier One Capital Ratio (Tier one capital divided by risk-weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958570-112826 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1H -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=117337116&loc=d3e65071-112826 + Details
Name: | us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The amount of Tier 1 Risk Based Capital required to be categorized as well capitalized under the regulatory framework for prompt corrective action. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The Tier 1 capital ratio (Tier 1 capital divided by risk weighted assets) required to be categorized as "well capitalized" under the regulatory framework for prompt corrective action. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Tier 1 capital divided by risk weighted assets as defined by regulations. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1H -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=117337116&loc=d3e65071-112826 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_TierOneRiskBasedCapitalToRiskWeightedAssets
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | dei_LegalEntityAxis=fcf_FirstCommonwealthFinancialCorporationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=fcf_FirstCommonwealthBankMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryAssetAxis=fcf_ActualMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryAssetAxis=fcf_RegulatoryMinimumforWellCapitalizedUnderFDICIPhaseInScheduleMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryAssetAxis=fcf_RegulatoryMinimumforWellCapitalizedUnderFDICIFullyPhasedInMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryAssetAxis=fcf_WellCapitalizedRatioMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |