XML 57 R47.htm IDEA: XBRL DOCUMENT
v3.23.3

Loans - Schedule of Collateral-dependent Loans (Detail) $ in Thousands | Sep. 30, 2023 USD ($)
--- | ---
Financing Receivable, Credit Quality Indicator [Line Items] |
Collateral dependent loans | $ 312
Agricultural Loan [Member] |
Financing Receivable, Credit Quality Indicator [Line Items] |
Collateral dependent loans | 311
Commercial and Industrial [Member] |
Financing Receivable, Credit Quality Indicator [Line Items] |
Collateral dependent loans | $ 1

X
- Definition Financial collateral dependent loans. + References No definition available. + Details
Name: | fmao_FinancialCollateralDependentLoans
Namespace Prefix: | fmao_
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/2009/role/commonPracticeRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-5 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479294/326-20-55-79 + Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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_CommercialPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |