XML 56 R47.htm IDEA: XBRL DOCUMENT
v3.25.2

Loans - Amortized Cost of Nonaccrual Loans by Portfolio Segment (Detail) - USD ($) $ in Thousands | Jun. 30, 2025 | Dec. 31, 2024
--- | --- | ---
Nonaccrual With No Allowance For Credit Loss [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Investment in nonaccrual loans | $ 3,252 | $ 2,392
Nonaccrual With No Allowance For Credit Loss [Member] | Consumer Real Estate [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Investment in nonaccrual loans | 2,556 | 1,637
Nonaccrual With No Allowance For Credit Loss [Member] | Agricultural Real Estate [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Investment in nonaccrual loans | 461 | 130
Nonaccrual With No Allowance For Credit Loss [Member] | Agricultural [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Investment in nonaccrual loans | 60 | 90
Nonaccrual With No Allowance For Credit Loss [Member] | Commercial Real Estate [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Investment in nonaccrual loans | 141 | 360
Nonaccrual With No Allowance For Credit Loss [Member] | Commercial & Industrial [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Investment in nonaccrual loans |  | 57
Nonaccrual With No Allowance For Credit Loss [Member] | Consumer [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Investment in nonaccrual loans | 34 | 118
Nonaccrual [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Investment in nonaccrual loans | 3,745 | 3,124
Nonaccrual [Member] | Consumer Real Estate [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Investment in nonaccrual loans | 3,049 | 2,369
Nonaccrual [Member] | Agricultural Real Estate [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Investment in nonaccrual loans | 461 | 130
Nonaccrual [Member] | Agricultural [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Investment in nonaccrual loans | 60 | 90
Nonaccrual [Member] | Commercial Real Estate [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Investment in nonaccrual loans | 141 | 360
Nonaccrual [Member] | Commercial & Industrial [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Investment in nonaccrual loans |  | 57
Nonaccrual [Member] | Consumer [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Investment in nonaccrual loans | $ 34 | $ 118

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/2009/role/commonPracticeRef -Topic 310 -SubTopic 20 -Name Accounting Standards Codification -Section 40 -Paragraph 7 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481628/310-20-40-7 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481990/310-10-45-2 + Details
Name: | us-gaap_AccountsNotesAndLoansReceivableLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amortized cost of financing receivable on nonaccrual status. Excludes net investment in lease. + References Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 7 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481962/310-10-50-7 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-K (SK) -Number 229 -Section 1405 -Paragraph a -Subparagraph (3) -Publisher SEC Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-K (SK) -Number 229 -Section 1405 -Paragraph a -Subparagraph (2) -Publisher SEC Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 16 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-16 + Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_FinancingReceivablesPeriodPastDueAxis=fmao_NonaccrualWithNoAllowanceForCreditLossMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ResidentialPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=fmao_AgricultureRealEstateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=fmao_AgriculturalLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialRealEstatePortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablesPeriodPastDueAxis=fmao_NonaccrualMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |