XML 32 R35.htm IDEA: XBRL DOCUMENT v2.4.1.9

Loans - Loans Individually Evaluated for Impairment by Portfolio Class of Loans (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Consumer Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	$ 253fmao_ImpairedFinancingReceivableRecordedInvestmentDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_ConsumerRealEstateMember	$ 181fmao_ImpairedFinancingReceivableRecordedInvestmentDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_ConsumerRealEstateMember
Unpaid Principal Balance	253fmao_ImpairedFinancingReceivableUnpaidPrincipalBalanceDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_ConsumerRealEstateMember	181fmao_ImpairedFinancingReceivableUnpaidPrincipalBalanceDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_ConsumerRealEstateMember
Related Allowance	35fmao_ImpairedFinancingReceivableRelatedAllowanceDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_ConsumerRealEstateMember	44fmao_ImpairedFinancingReceivableRelatedAllowanceDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_ConsumerRealEstateMember
Average Recorded Investment	269fmao_FinancingReceivableAverageRecordedInvestment / us-gaap_FinancialInstrumentAxis = fmao_ConsumerRealEstateMember	668fmao_FinancingReceivableAverageRecordedInvestment / us-gaap_FinancialInstrumentAxis = fmao_ConsumerRealEstateMember
Interest Income Recognized	3fmao_ImpairedFinancingReceivablesInterestIncomeRecognized / us-gaap_FinancialInstrumentAxis = fmao_ConsumerRealEstateMember	1fmao_ImpairedFinancingReceivablesInterestIncomeRecognized / us-gaap_FinancialInstrumentAxis = fmao_ConsumerRealEstateMember
Agricultural Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment		141fmao_ImpairedFinancingReceivableRecordedInvestmentDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_AgricultureRealEstateMember
Unpaid Principal Balance		141fmao_ImpairedFinancingReceivableUnpaidPrincipalBalanceDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_AgricultureRealEstateMember
Average Recorded Investment		505fmao_FinancingReceivableAverageRecordedInvestment / us-gaap_FinancialInstrumentAxis = fmao_AgricultureRealEstateMember
Agricultural [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	24fmao_ImpairedFinancingReceivableRecordedInvestmentDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_AgriculturalLoanMember
Unpaid Principal Balance	24fmao_ImpairedFinancingReceivableUnpaidPrincipalBalanceDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_AgriculturalLoanMember
Related Allowance	24fmao_ImpairedFinancingReceivableRelatedAllowanceDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_AgriculturalLoanMember
Average Recorded Investment	24fmao_FinancingReceivableAverageRecordedInvestment / us-gaap_FinancialInstrumentAxis = fmao_AgriculturalLoanMember
Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	1,139fmao_ImpairedFinancingReceivableRecordedInvestmentDuringPeriod / us-gaap_FinancialInstrumentAxis = us-gaap_CommercialRealEstateMember	1,385fmao_ImpairedFinancingReceivableRecordedInvestmentDuringPeriod / us-gaap_FinancialInstrumentAxis = us-gaap_CommercialRealEstateMember
Unpaid Principal Balance	1,139fmao_ImpairedFinancingReceivableUnpaidPrincipalBalanceDuringPeriod / us-gaap_FinancialInstrumentAxis = us-gaap_CommercialRealEstateMember	1,385fmao_ImpairedFinancingReceivableUnpaidPrincipalBalanceDuringPeriod / us-gaap_FinancialInstrumentAxis = us-gaap_CommercialRealEstateMember
Related Allowance	131fmao_ImpairedFinancingReceivableRelatedAllowanceDuringPeriod / us-gaap_FinancialInstrumentAxis = us-gaap_CommercialRealEstateMember	107fmao_ImpairedFinancingReceivableRelatedAllowanceDuringPeriod / us-gaap_FinancialInstrumentAxis = us-gaap_CommercialRealEstateMember
Average Recorded Investment	852fmao_FinancingReceivableAverageRecordedInvestment / us-gaap_FinancialInstrumentAxis = us-gaap_CommercialRealEstateMember	2,396fmao_FinancingReceivableAverageRecordedInvestment / us-gaap_FinancialInstrumentAxis = us-gaap_CommercialRealEstateMember
Interest Income Recognized		14fmao_ImpairedFinancingReceivablesInterestIncomeRecognized / us-gaap_FinancialInstrumentAxis = us-gaap_CommercialRealEstateMember
Commercial and Industrial [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	827fmao_ImpairedFinancingReceivableRecordedInvestmentDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_CommercialAndIndustrialMember	352fmao_ImpairedFinancingReceivableRecordedInvestmentDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_CommercialAndIndustrialMember
Unpaid Principal Balance	827fmao_ImpairedFinancingReceivableUnpaidPrincipalBalanceDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_CommercialAndIndustrialMember	352fmao_ImpairedFinancingReceivableUnpaidPrincipalBalanceDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_CommercialAndIndustrialMember
Related Allowance	238fmao_ImpairedFinancingReceivableRelatedAllowanceDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_CommercialAndIndustrialMember	110fmao_ImpairedFinancingReceivableRelatedAllowanceDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_CommercialAndIndustrialMember
Average Recorded Investment	806fmao_FinancingReceivableAverageRecordedInvestment / us-gaap_FinancialInstrumentAxis = fmao_CommercialAndIndustrialMember	1,993fmao_FinancingReceivableAverageRecordedInvestment / us-gaap_FinancialInstrumentAxis = fmao_CommercialAndIndustrialMember
Interest Income Recognized	7fmao_ImpairedFinancingReceivablesInterestIncomeRecognized / us-gaap_FinancialInstrumentAxis = fmao_CommercialAndIndustrialMember	16fmao_ImpairedFinancingReceivablesInterestIncomeRecognized / us-gaap_FinancialInstrumentAxis = fmao_CommercialAndIndustrialMember
Consumer [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	7fmao_FinancingReceivableAverageRecordedInvestment / us-gaap_FinancialInstrumentAxis = us-gaap_ConsumerLoanMember
With No Related Allowance Recorded [Member] | Consumer Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	157fmao_ImpairedFinancingReceivableRecordedInvestmentDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_ConsumerRealEstateMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithNoRelatedAllowanceRecordedMember	72fmao_ImpairedFinancingReceivableRecordedInvestmentDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_ConsumerRealEstateMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithNoRelatedAllowanceRecordedMember
Unpaid Principal Balance	157fmao_ImpairedFinancingReceivableUnpaidPrincipalBalanceDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_ConsumerRealEstateMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithNoRelatedAllowanceRecordedMember	72fmao_ImpairedFinancingReceivableUnpaidPrincipalBalanceDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_ConsumerRealEstateMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithNoRelatedAllowanceRecordedMember
Average Recorded Investment	173fmao_FinancingReceivableAverageRecordedInvestment / us-gaap_FinancialInstrumentAxis = fmao_ConsumerRealEstateMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithNoRelatedAllowanceRecordedMember	145fmao_FinancingReceivableAverageRecordedInvestment / us-gaap_FinancialInstrumentAxis = fmao_ConsumerRealEstateMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithNoRelatedAllowanceRecordedMember
With No Related Allowance Recorded [Member] | Agricultural Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment		141fmao_ImpairedFinancingReceivableRecordedInvestmentDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_AgricultureRealEstateMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithNoRelatedAllowanceRecordedMember
Unpaid Principal Balance		141fmao_ImpairedFinancingReceivableUnpaidPrincipalBalanceDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_AgricultureRealEstateMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithNoRelatedAllowanceRecordedMember
Average Recorded Investment		328fmao_FinancingReceivableAverageRecordedInvestment / us-gaap_FinancialInstrumentAxis = fmao_AgricultureRealEstateMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithNoRelatedAllowanceRecordedMember
With No Related Allowance Recorded [Member] | Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment		904fmao_ImpairedFinancingReceivableRecordedInvestmentDuringPeriod / us-gaap_FinancialInstrumentAxis = us-gaap_CommercialRealEstateMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithNoRelatedAllowanceRecordedMember
Unpaid Principal Balance		904fmao_ImpairedFinancingReceivableUnpaidPrincipalBalanceDuringPeriod / us-gaap_FinancialInstrumentAxis = us-gaap_CommercialRealEstateMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithNoRelatedAllowanceRecordedMember
Average Recorded Investment		2,112fmao_FinancingReceivableAverageRecordedInvestment / us-gaap_FinancialInstrumentAxis = us-gaap_CommercialRealEstateMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithNoRelatedAllowanceRecordedMember
Interest Income Recognized		14fmao_ImpairedFinancingReceivablesInterestIncomeRecognized / us-gaap_FinancialInstrumentAxis = us-gaap_CommercialRealEstateMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithNoRelatedAllowanceRecordedMember
With No Related Allowance Recorded [Member] | Commercial and Industrial [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	467fmao_ImpairedFinancingReceivableRecordedInvestmentDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithNoRelatedAllowanceRecordedMember
Unpaid Principal Balance	467fmao_ImpairedFinancingReceivableUnpaidPrincipalBalanceDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithNoRelatedAllowanceRecordedMember
Average Recorded Investment	469fmao_FinancingReceivableAverageRecordedInvestment / us-gaap_FinancialInstrumentAxis = fmao_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithNoRelatedAllowanceRecordedMember	25fmao_FinancingReceivableAverageRecordedInvestment / us-gaap_FinancialInstrumentAxis = fmao_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithNoRelatedAllowanceRecordedMember
Interest Income Recognized	7fmao_ImpairedFinancingReceivablesInterestIncomeRecognized / us-gaap_FinancialInstrumentAxis = fmao_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithNoRelatedAllowanceRecordedMember	9fmao_ImpairedFinancingReceivablesInterestIncomeRecognized / us-gaap_FinancialInstrumentAxis = fmao_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithNoRelatedAllowanceRecordedMember
With a Specific Allowance Recorded [Member] | Consumer Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	96fmao_ImpairedFinancingReceivableRecordedInvestmentDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_ConsumerRealEstateMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithSpecificAllowanceRecordedMember	109fmao_ImpairedFinancingReceivableRecordedInvestmentDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_ConsumerRealEstateMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithSpecificAllowanceRecordedMember
Unpaid Principal Balance	96fmao_ImpairedFinancingReceivableUnpaidPrincipalBalanceDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_ConsumerRealEstateMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithSpecificAllowanceRecordedMember	109fmao_ImpairedFinancingReceivableUnpaidPrincipalBalanceDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_ConsumerRealEstateMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithSpecificAllowanceRecordedMember
Related Allowance	35fmao_ImpairedFinancingReceivableRelatedAllowanceDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_ConsumerRealEstateMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithSpecificAllowanceRecordedMember	44fmao_ImpairedFinancingReceivableRelatedAllowanceDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_ConsumerRealEstateMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithSpecificAllowanceRecordedMember
Average Recorded Investment	96fmao_FinancingReceivableAverageRecordedInvestment / us-gaap_FinancialInstrumentAxis = fmao_ConsumerRealEstateMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithSpecificAllowanceRecordedMember	523fmao_FinancingReceivableAverageRecordedInvestment / us-gaap_FinancialInstrumentAxis = fmao_ConsumerRealEstateMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithSpecificAllowanceRecordedMember
Interest Income Recognized	3fmao_ImpairedFinancingReceivablesInterestIncomeRecognized / us-gaap_FinancialInstrumentAxis = fmao_ConsumerRealEstateMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithSpecificAllowanceRecordedMember	1fmao_ImpairedFinancingReceivablesInterestIncomeRecognized / us-gaap_FinancialInstrumentAxis = fmao_ConsumerRealEstateMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithSpecificAllowanceRecordedMember
With a Specific Allowance Recorded [Member] | Agricultural Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment		177fmao_FinancingReceivableAverageRecordedInvestment / us-gaap_FinancialInstrumentAxis = fmao_AgricultureRealEstateMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithSpecificAllowanceRecordedMember
With a Specific Allowance Recorded [Member] | Agricultural [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	24fmao_ImpairedFinancingReceivableRecordedInvestmentDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_AgriculturalLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithSpecificAllowanceRecordedMember
Unpaid Principal Balance	24fmao_ImpairedFinancingReceivableUnpaidPrincipalBalanceDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_AgriculturalLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithSpecificAllowanceRecordedMember
Related Allowance	24fmao_ImpairedFinancingReceivableRelatedAllowanceDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_AgriculturalLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithSpecificAllowanceRecordedMember
Average Recorded Investment	24fmao_FinancingReceivableAverageRecordedInvestment / us-gaap_FinancialInstrumentAxis = fmao_AgriculturalLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithSpecificAllowanceRecordedMember
With a Specific Allowance Recorded [Member] | Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	1,139fmao_ImpairedFinancingReceivableRecordedInvestmentDuringPeriod / us-gaap_FinancialInstrumentAxis = us-gaap_CommercialRealEstateMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithSpecificAllowanceRecordedMember	481fmao_ImpairedFinancingReceivableRecordedInvestmentDuringPeriod / us-gaap_FinancialInstrumentAxis = us-gaap_CommercialRealEstateMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithSpecificAllowanceRecordedMember
Unpaid Principal Balance	1,139fmao_ImpairedFinancingReceivableUnpaidPrincipalBalanceDuringPeriod / us-gaap_FinancialInstrumentAxis = us-gaap_CommercialRealEstateMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithSpecificAllowanceRecordedMember	481fmao_ImpairedFinancingReceivableUnpaidPrincipalBalanceDuringPeriod / us-gaap_FinancialInstrumentAxis = us-gaap_CommercialRealEstateMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithSpecificAllowanceRecordedMember
Related Allowance	131fmao_ImpairedFinancingReceivableRelatedAllowanceDuringPeriod / us-gaap_FinancialInstrumentAxis = us-gaap_CommercialRealEstateMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithSpecificAllowanceRecordedMember	107fmao_ImpairedFinancingReceivableRelatedAllowanceDuringPeriod / us-gaap_FinancialInstrumentAxis = us-gaap_CommercialRealEstateMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithSpecificAllowanceRecordedMember
Average Recorded Investment	852fmao_FinancingReceivableAverageRecordedInvestment / us-gaap_FinancialInstrumentAxis = us-gaap_CommercialRealEstateMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithSpecificAllowanceRecordedMember	284fmao_FinancingReceivableAverageRecordedInvestment / us-gaap_FinancialInstrumentAxis = us-gaap_CommercialRealEstateMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithSpecificAllowanceRecordedMember
With a Specific Allowance Recorded [Member] | Commercial and Industrial [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	360fmao_ImpairedFinancingReceivableRecordedInvestmentDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithSpecificAllowanceRecordedMember	352fmao_ImpairedFinancingReceivableRecordedInvestmentDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithSpecificAllowanceRecordedMember
Unpaid Principal Balance	360fmao_ImpairedFinancingReceivableUnpaidPrincipalBalanceDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithSpecificAllowanceRecordedMember	352fmao_ImpairedFinancingReceivableUnpaidPrincipalBalanceDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithSpecificAllowanceRecordedMember
Related Allowance	238fmao_ImpairedFinancingReceivableRelatedAllowanceDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithSpecificAllowanceRecordedMember	110fmao_ImpairedFinancingReceivableRelatedAllowanceDuringPeriod / us-gaap_FinancialInstrumentAxis = fmao_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithSpecificAllowanceRecordedMember
Average Recorded Investment	337fmao_FinancingReceivableAverageRecordedInvestment / us-gaap_FinancialInstrumentAxis = fmao_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithSpecificAllowanceRecordedMember	1,968fmao_FinancingReceivableAverageRecordedInvestment / us-gaap_FinancialInstrumentAxis = fmao_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithSpecificAllowanceRecordedMember
Interest Income Recognized		7fmao_ImpairedFinancingReceivablesInterestIncomeRecognized / us-gaap_FinancialInstrumentAxis = fmao_CommercialAndIndustrialMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithSpecificAllowanceRecordedMember
With a Specific Allowance Recorded [Member] | Consumer [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	$ 7fmao_FinancingReceivableAverageRecordedInvestment / us-gaap_FinancialInstrumentAxis = us-gaap_ConsumerLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fmao_WithSpecificAllowanceRecordedMember

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- Definition

Amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

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Impaired financing receivable related allowance during period.

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Impaired financing receivables interest income recognized.

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Impaired financing receivable unpaid principal balance during period.

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