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Number of modified loans to borrowers experiencing financial difficulty during the period.

No definition available.

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Number of loans for which had payment deferral.

No definition available.

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Refers to the past due period for a previously modified loan, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

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Refers to the past due period after which a loan is considered in default, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

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Number of loans for which contractual term extended.

No definition available.

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Number of real estate borrowers.

No definition available.

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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.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
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Amortized cost of financing receivable with payment default in current period and modified within previous 12 months preceding payment default for debtor experiencing financial difficulty.

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Period of increase in weighted-average maturity of financing receivable modified for debtor experiencing financial difficulty, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
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Amortized cost, after allowance for credit loss, of financing receivable. Excludes financing receivable covered under loss sharing agreement and net investment in lease.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
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Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=fmcb_RealEstateResidentialAndHomeEquityPortfolioSegmentMember
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Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=fmcb_AgriculturalRealEstatePortfolioSegmentMember
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Data Type:	na
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Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=fmcb_AgriculturalPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	us-gaap_LoanRestructuringModificationAxis=us-gaap_ExtendedMaturityMember
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Data Type:	na
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Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=fmcb_CommercialIndustrialMember
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Data Type:	na
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Name:	us-gaap_LoanRestructuringModificationAxis=us-gaap_PaymentDeferralMember
Namespace Prefix:
Data Type:	na
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Name:	us-gaap_PledgingPurposeAxis=us-gaap_FederalHomeLoanBankAdvancesMember
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