XML 71 R61.htm IDEA: XBRL DOCUMENT
v3.25.3

FAIR VALUES OF FINANCIAL INSTRUMENTS - Summary of Unobservable Inputs Used in Recurring and Nonrecurring Level 3 Fair Value Measurements Other than Goodwill (Details) - Significant Unobservable Inputs (Level 3) $ in Thousands | Sep. 30, 2025 USD ($) | Dec. 31, 2024 USD ($)
--- | --- | ---
State and municipal securities | Discounted cash flow |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Fair Value | $ 1,963 | $ 2,381
State and municipal securities | Discounted cash flow | Minimum |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Maturity/Call date | 1 month | 1 month
State and municipal securities | Discounted cash flow | Maximum |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Maturity/Call date | 5 years | 6 years
State and municipal securities | Discounted cash flow | Discount rate | Minimum |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Measurement input | 0.034 | 0.036
State and municipal securities | Discounted cash flow | Discount rate | Maximum |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Measurement input | 0.057 | 0.047
State and municipal securities | Discounted cash flow | Weighted-average coupon | Weighted-average |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Measurement input | 0.036 | 0.036
Corporate obligations | Discounted cash flow |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Fair Value | $ 31 |
Corporate obligations | Discounted cash flow | Weighted-average coupon | Weighted-average |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Measurement input | 0 |
Corporate obligations | Discounted cash flow | Risk free rate |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Measurement input | 0.0026 |
Corporate obligations | Discounted cash flow | plus premium for illiquidity (basis points) |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Measurement input | 0.0200 |
Corporate obligations and U.S. Government-sponsored mortgage-backed securities | Discounted cash flow |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Fair Value |  | $ 35
Corporate obligations and U.S. Government-sponsored mortgage-backed securities | Discounted cash flow | Weighted-average coupon | Weighted-average |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Measurement input |  | 0
Corporate obligations and U.S. Government-sponsored mortgage-backed securities | Discounted cash flow | Risk free rate |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Measurement input |  | 0.0026
Corporate obligations and U.S. Government-sponsored mortgage-backed securities | Discounted cash flow | plus premium for illiquidity (basis points) |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Measurement input |  | 0.0200
Collateral dependent loans | Collateral based measurements |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Fair Value | $ 66,708 | $ 46,810
Collateral dependent loans | Collateral based measurements | Discount to reflect current market conditions and ultimate collectability | Minimum |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Measurement input | 0.01 | 0
Collateral dependent loans | Collateral based measurements | Discount to reflect current market conditions and ultimate collectability | Maximum |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Measurement input | 0.16 | 0.16
Collateral dependent loans | Collateral based measurements | Weighted-average discount by loan balance | Weighted-average |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Measurement input | 0.015 | 0.126

X
- Definition Impaired Loans, Measurement Input + References No definition available. + Details
Name: | frme_ImpairedLoansMeasurementInput
Namespace Prefix: | frme_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | instant

X
- Definition Fair value portion of asset recognized for present right to economic benefit. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 100 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-100 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_AssetsFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Value of input used to measure investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 103 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-103 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2)(i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_DebtSecuritiesAvailableForSaleMeasurementInput
Namespace Prefix: | us-gaap_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | instant

X
- Definition Period between issuance and maturity of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2)(i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_DebtSecuritiesAvailableForSaleTerm
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
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 Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 805 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 8 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479328/805-10-50-8 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 805 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 43 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479303/805-10-55-43 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 4: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 103 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-103 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2)(i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_USStatesAndPoliticalSubdivisionsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ValuationTechniqueAxis=us-gaap_ValuationTechniqueDiscountedCashFlowMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputDiscountRateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=frme_MeasurementInputCouponRateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_WeightedAverageMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputRiskFreeInterestRateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputDiscountForLackOfMarketabilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=frme_CorporateObligationsandU.S.GovernmentSponsoredMortgageBackedSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=frme_CollateralDependentLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ValuationTechniqueAxis=frme_CollateralBasedMeasurementsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputComparabilityAdjustmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=frme_MeasurementInputDiscountByLoanBalanceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |