XML 79 R49.htm IDEA: XBRL DOCUMENT v2.4.1.9
Loans and Allowance - Credit Quality of Loan Portfolio by Loan Class (Details) (USD $)
In Thousands, unless otherwise specified
Mar. 31, 2015
Dec. 31, 2014
Financing Receivable, Recorded Investment [Line Items]    
Loans $ 3,965,532us-gaap_LoansAndLeasesReceivableGrossCarryingAmount $ 3,924,865us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
Commercial and industrial loans    
Financing Receivable, Recorded Investment [Line Items]    
Loans 938,937us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= frme_CommercialAndIndustrialLoansMember		 896,688us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= frme_CommercialAndIndustrialLoansMember
Agricultural production financing and other loans to farmers    
Financing Receivable, Recorded Investment [Line Items]    
Loans 95,652us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= frme_FarmingAndAgricultureMember		 104,927us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= frme_FarmingAndAgricultureMember
Real estate loans - Construction    
Financing Receivable, Recorded Investment [Line Items]    
Loans 237,036us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConstructionLoansMember		 207,221us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConstructionLoansMember
Real estate loans - Commercial and farmland    
Financing Receivable, Recorded Investment [Line Items]    
Loans 1,646,418us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= frme_CommercialAndFarmLandLoansMember		 1,672,661us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= frme_CommercialAndFarmLandLoansMember
Real estate loans - Residential    
Financing Receivable, Recorded Investment [Line Items]    
Loans 640,451us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialRealEstateMember		 647,315us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialRealEstateMember
Real estate loans - Home equity    
Financing Receivable, Recorded Investment [Line Items]    
Loans 286,914us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember		 286,529us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
Individuals' loans for household and other personal expenditures    
Financing Receivable, Recorded Investment [Line Items]    
Loans 70,223us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember		 73,400us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
Lease financing receivables, net of unearned income    
Financing Receivable, Recorded Investment [Line Items]    
Loans 853us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_FinanceLeasesFinancingReceivableMember		 1,106us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_FinanceLeasesFinancingReceivableMember
Other loans    
Financing Receivable, Recorded Investment [Line Items]    
Loans 49,048us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= frme_OtherLoansMember		 35,018us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= frme_OtherLoansMember
Commercial Pass    
Financing Receivable, Recorded Investment [Line Items]    
Loans 2,901,056us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember		 2,849,876us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
Commercial Pass | Commercial and industrial loans    
Financing Receivable, Recorded Investment [Line Items]    
Loans 867,157us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= frme_CommercialAndIndustrialLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember		 823,732us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= frme_CommercialAndIndustrialLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
Commercial Pass | Agricultural production financing and other loans to farmers    
Financing Receivable, Recorded Investment [Line Items]    
Loans 89,454us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= frme_FarmingAndAgricultureMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember		 96,155us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= frme_FarmingAndAgricultureMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
Commercial Pass | Real estate loans - Construction    
Financing Receivable, Recorded Investment [Line Items]    
Loans 217,161us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConstructionLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember		 185,394us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConstructionLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
Commercial Pass | Real estate loans - Commercial and farmland    
Financing Receivable, Recorded Investment [Line Items]    
Loans 1,521,989us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= frme_CommercialAndFarmLandLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember		 1,552,781us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= frme_CommercialAndFarmLandLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
Commercial Pass | Real estate loans - Residential    
Financing Receivable, Recorded Investment [Line Items]    
Loans 149,021us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialRealEstateMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember		 149,430us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialRealEstateMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
Commercial Pass | Real estate loans - Home equity    
Financing Receivable, Recorded Investment [Line Items]    
Loans 6,478us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember		 6,368us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
Commercial Pass | Lease financing receivables, net of unearned income    
Financing Receivable, Recorded Investment [Line Items]    
Loans 748us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_FinanceLeasesFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember		 998us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_FinanceLeasesFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
Commercial Pass | Other loans    
Financing Receivable, Recorded Investment [Line Items]    
Loans 49,048us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= frme_OtherLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember		 35,018us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= frme_OtherLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
Commercial Special Mention    
Financing Receivable, Recorded Investment [Line Items]    
Loans 86,185us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember		 64,631us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
Commercial Special Mention | Commercial and industrial loans    
Financing Receivable, Recorded Investment [Line Items]    
Loans 28,888us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= frme_CommercialAndIndustrialLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember		 24,455us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= frme_CommercialAndIndustrialLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
Commercial Special Mention | Agricultural production financing and other loans to farmers    
Financing Receivable, Recorded Investment [Line Items]    
Loans 2,469us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= frme_FarmingAndAgricultureMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember		 1,195us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= frme_FarmingAndAgricultureMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
Commercial Special Mention | Real estate loans - Construction    
Financing Receivable, Recorded Investment [Line Items]    
Loans 2,359us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConstructionLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember		 3,164us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConstructionLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
Commercial Special Mention | Real estate loans - Commercial and farmland    
Financing Receivable, Recorded Investment [Line Items]    
Loans 48,219us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= frme_CommercialAndFarmLandLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember		 29,484us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= frme_CommercialAndFarmLandLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
Commercial Special Mention | Real estate loans - Residential    
Financing Receivable, Recorded Investment [Line Items]    
Loans 4,232us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialRealEstateMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember		 6,321us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialRealEstateMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
Commercial Special Mention | Real estate loans - Home equity    
Financing Receivable, Recorded Investment [Line Items]    
Loans 18us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember		 12us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
Commercial Special Mention | Other loans    
Financing Receivable, Recorded Investment [Line Items]    
Loans     
Commercial Substandard    
Financing Receivable, Recorded Investment [Line Items]    
Loans 134,988us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember		 160,608us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
Commercial Substandard | Commercial and industrial loans    
Financing Receivable, Recorded Investment [Line Items]    
Loans 41,023us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= frme_CommercialAndIndustrialLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember		 48,226us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= frme_CommercialAndIndustrialLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
Commercial Substandard | Agricultural production financing and other loans to farmers    
Financing Receivable, Recorded Investment [Line Items]    
Loans 3,729us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= frme_FarmingAndAgricultureMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember		 7,577us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= frme_FarmingAndAgricultureMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
Commercial Substandard | Real estate loans - Construction    
Financing Receivable, Recorded Investment [Line Items]    
Loans 2,493us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConstructionLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember		 2,928us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConstructionLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
Commercial Substandard | Real estate loans - Commercial and farmland    
Financing Receivable, Recorded Investment [Line Items]    
Loans 76,208us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= frme_CommercialAndFarmLandLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember		 90,161us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= frme_CommercialAndFarmLandLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
Commercial Substandard | Real estate loans - Residential    
Financing Receivable, Recorded Investment [Line Items]    
Loans 10,845us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialRealEstateMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember		 10,918us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialRealEstateMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
Commercial Substandard | Real estate loans - Home equity    
Financing Receivable, Recorded Investment [Line Items]    
Loans 585us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember		 690us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
Commercial Substandard | Lease financing receivables, net of unearned income    
Financing Receivable, Recorded Investment [Line Items]    
Loans 105us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_FinanceLeasesFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember		 108us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_FinanceLeasesFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
Commercial Substandard | Other loans    
Financing Receivable, Recorded Investment [Line Items]    
Loans      
Commercial Doubtful    
Financing Receivable, Recorded Investment [Line Items]    
Loans 1,869us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember		 275us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
Commercial Doubtful | Commercial and industrial loans    
Financing Receivable, Recorded Investment [Line Items]    
Loans 1,869us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= frme_CommercialAndIndustrialLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember		 275us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= frme_CommercialAndIndustrialLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
Commercial Doubtful | Real estate loans - Residential    
Financing Receivable, Recorded Investment [Line Items]    
Loans      
Consumer Performing    
Financing Receivable, Recorded Investment [Line Items]    
Loans 829,048us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 837,296us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember
Consumer Performing | Real estate loans - Construction    
Financing Receivable, Recorded Investment [Line Items]    
Loans 14,582us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConstructionLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 15,588us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConstructionLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember
Consumer Performing | Real estate loans - Residential    
Financing Receivable, Recorded Investment [Line Items]    
Loans 466,806us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialRealEstateMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 470,972us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialRealEstateMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember
Consumer Performing | Real estate loans - Home equity    
Financing Receivable, Recorded Investment [Line Items]    
Loans 277,578us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 277,571us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember
Consumer Performing | Individuals' loans for household and other personal expenditures    
Financing Receivable, Recorded Investment [Line Items]    
Loans 70,082us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 73,165us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember
Consumer Non-Performing    
Financing Receivable, Recorded Investment [Line Items]    
Loans 12,386us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_NonperformingFinancingReceivableMember		 12,179us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_NonperformingFinancingReceivableMember
Consumer Non-Performing | Real estate loans - Construction    
Financing Receivable, Recorded Investment [Line Items]    
Loans 441us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConstructionLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_NonperformingFinancingReceivableMember		 147us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConstructionLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_NonperformingFinancingReceivableMember
Consumer Non-Performing | Real estate loans - Commercial and farmland    
Financing Receivable, Recorded Investment [Line Items]    
Loans 2us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= frme_CommercialAndFarmLandLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_NonperformingFinancingReceivableMember		 235us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= frme_CommercialAndFarmLandLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_NonperformingFinancingReceivableMember
Consumer Non-Performing | Real estate loans - Residential    
Financing Receivable, Recorded Investment [Line Items]    
Loans 9,547us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialRealEstateMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_NonperformingFinancingReceivableMember		 9,674us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialRealEstateMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_NonperformingFinancingReceivableMember
Consumer Non-Performing | Real estate loans - Home equity    
Financing Receivable, Recorded Investment [Line Items]    
Loans 2,255us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_NonperformingFinancingReceivableMember		 1,888us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_NonperformingFinancingReceivableMember
Consumer Non-Performing | Individuals' loans for household and other personal expenditures    
Financing Receivable, Recorded Investment [Line Items]    
Loans $ 141us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_NonperformingFinancingReceivableMember		 $ 235us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_NonperformingFinancingReceivableMember