XML 49 R39.htm IDEA: XBRL DOCUMENT
v3.24.3

INVESTMENT SECURITIES - Amortized Cost of Investment Securities Held to Maturity (Details) - USD ($) $ in Thousands | Sep. 30, 2024 | Dec. 31, 2023
--- | --- | ---
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | $ 2,108,894 | $ 2,184,497
Aaa |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 1,132,647 |
Aa1 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 160,281 |
Aa2 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 177,858 |
Aa3 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 112,393 |
A1 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 141,608 |
A2 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 20,313 |
Non-rated |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 363,794 |
U.S. Government-sponsored agency securities |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 361,335 | 374,002
U.S. Government-sponsored agency securities | Aaa |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 361,335 |
U.S. Government-sponsored agency securities | Aa1 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 0 |
U.S. Government-sponsored agency securities | Aa2 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 0 |
U.S. Government-sponsored agency securities | Aa3 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 0 |
U.S. Government-sponsored agency securities | A1 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 0 |
U.S. Government-sponsored agency securities | A2 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 0 |
U.S. Government-sponsored agency securities | Non-rated |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 0 |
State and municipal |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 1,087,980 | 1,099,201
State and municipal | Aaa |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 113,233 |
State and municipal | Aa1 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 160,281 |
State and municipal | Aa2 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 177,858 |
State and municipal | Aa3 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 112,393 |
State and municipal | A1 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 141,608 |
State and municipal | A2 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 20,313 |
State and municipal | Non-rated |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 362,294 |
U.S. Government-sponsored mortgage-backed securities |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 658,079 | $ 709,794
U.S. Government-sponsored mortgage-backed securities | Aaa |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 658,079 |
U.S. Government-sponsored mortgage-backed securities | Aa1 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 0 |
U.S. Government-sponsored mortgage-backed securities | Aa2 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 0 |
U.S. Government-sponsored mortgage-backed securities | Aa3 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 0 |
U.S. Government-sponsored mortgage-backed securities | A1 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 0 |
U.S. Government-sponsored mortgage-backed securities | A2 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 0 |
U.S. Government-sponsored mortgage-backed securities | Non-rated |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 0 |
Foreign investment |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 1,500 |
Foreign investment | Aaa |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 0 |
Foreign investment | Aa1 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 0 |
Foreign investment | Aa2 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 0 |
Foreign investment | Aa3 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 0 |
Foreign investment | A1 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 0 |
Foreign investment | A2 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 0 |
Foreign investment | Non-rated |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | $ 1,500 |

X
- Definition Amount excluding accrued interest, before allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479344/326-20-45-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3B -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-3B Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-5 + Details
Name: | us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
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/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-5 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (aaa) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-5 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-5 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-5 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-5 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-5 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-5 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f)(3) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-5 Reference 9: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f)(4) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-5 Reference 10: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5A -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-5A Reference 11: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5A -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-5A Reference 12: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5A -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-5A Reference 13: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5B -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-5B Reference 14: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5B -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-5B Reference 15: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5B -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-5B Reference 16: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5B -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-5B Reference 17: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5B -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-5B Reference 18: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-5 + Details
Name: | us-gaap_ScheduleOfHeldToMaturitySecuritiesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | srt_CreditRatingMoodysAxis=srt_MoodysAaaRatingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CreditRatingMoodysAxis=srt_MoodysAa1RatingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CreditRatingMoodysAxis=srt_MoodysAa2RatingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CreditRatingMoodysAxis=srt_MoodysAa3RatingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CreditRatingMoodysAxis=srt_MoodysA1RatingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CreditRatingMoodysAxis=srt_MoodysA2RatingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CreditRatingMoodysAxis=frme_NonRatedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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