XML 17 R54.htm IDEA: XBRL DOCUMENT
v2.4.1.9

Loans - Additional Information (Detail) (USD $) | 1 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Jan. 31, 2010 | Dec. 31, 2014 | Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Residential mortgage loan |  | $ 20,800,000 fmb_ResidentialMortgageLoan | $ 24,300,000 fmb_ResidentialMortgageLoan
Percentage of delinquent loan | 2.85%fmb_PercentageOfDelinquentLoan |  |
Delinquent loans least percentage |  |  | 0.25%fmb_DelinquentLoansLeastPercentage
Impaired loans classified as troubled debt restructured |  | 797,200 fmb_ImpairedLoansClassifiedAsTroubledDebtRestructured | 861,200 fmb_ImpairedLoansClassifiedAsTroubledDebtRestructured
Maximum time for re-evaluation (in months) |  | 12 months |
Re-evaluation period for real estate |  | 2 years |
Unsecured consumer loans, credit card credits and overdraft lines of credit reach |  | 90 days |
Delinquent period for charging down consumer loans |  | 120 days |
Delinquent period for charging down commercial and agricultural credits |  | 120 days |
Consumer Real Estate [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans held for sale |  | $ 459,000 us-gaap_LoansReceivableHeldForSaleNet / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = fmb_ConsumerRealEstateMember | $ 566,000 us-gaap_LoansReceivableHeldForSaleNet / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = fmb_ConsumerRealEstateMember
Maximum [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Leverage position of balance sheet |  | 1.50 fmb_LeveragePositionOfBalanceSheet / us-gaap_RangeAxis = us-gaap_MaximumMember |
Leverage position of customers |  | 2.00 fmb_LeverageRatio / us-gaap_RangeAxis = us-gaap_MaximumMember |
Minimum [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Repayment period of loan with a reasonable reduction of principal balance |  | 2 years |

X
- Definition Delinquent Loans Least Percentage + References No definition available. + Details
Name: | fmb_DelinquentLoansLeastPercentage
Namespace Prefix: | fmb_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Delinquent period for charging down commercial and agricultural credits. + References No definition available. + Details
Name: | fmb_DelinquentPeriodForChargingDownCommercialAndAgriculturalCredits
Namespace Prefix: | fmb_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Delinquent period for charging down consumer loans + References No definition available. + Details
Name: | fmb_DelinquentPeriodForChargingDownConsumerLoans
Namespace Prefix: | fmb_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Impaired loans classified as troubled debt restructured. + References No definition available. + Details
Name: | fmb_ImpairedLoansClassifiedAsTroubledDebtRestructured
Namespace Prefix: | fmb_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Leverage position of balance sheet. + References No definition available. + Details
Name: | fmb_LeveragePositionOfBalanceSheet
Namespace Prefix: | fmb_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | duration

X
- Definition Leverage ratio. + References No definition available. + Details
Name: | fmb_LeverageRatio
Namespace Prefix: | fmb_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | duration

X
- Definition Maximum time for reevaluation. + References No definition available. + Details
Name: | fmb_MaximumTimeForReevaluation
Namespace Prefix: | fmb_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage Of Delinquent Loan + References No definition available. + Details
Name: | fmb_PercentageOfDelinquentLoan
Namespace Prefix: | fmb_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Re evaluation period for real estate. + References No definition available. + Details
Name: | fmb_ReEvaluationPeriodForRealEstate
Namespace Prefix: | fmb_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Repayment period of loan with reasonable reduction of principal balance. + References No definition available. + Details
Name: | fmb_RepaymentPeriodOfLoanWithReasonableReductionOfPrincipalBalance
Namespace Prefix: | fmb_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Residential mortgage loan. + References No definition available. + Details
Name: | fmb_ResidentialMortgageLoan
Namespace Prefix: | fmb_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Unsecured consumer loans credit card credits and overdraft. + References No definition available. + Details
Name: | fmb_UnsecuredConsumerLoansCreditCardCreditsAndOverdraft
Namespace Prefix: | fmb_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_AccountsNotesAndLoansReceivableLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount classified as loans attributable to disposal group held for sale or disposed of. Excludes loans and leases covered under loss sharing agreements and loans classified as debt securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=28367877&loc=d3e4428-111522 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 7 -Subparagraph a -Article 9 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.7(a)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 35 -Paragraph 49 -URI http://asc.fasb.org/extlink&oid=35742846&loc=d3e3084-111518 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 948 -SubTopic 310 -Section 30 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6490209&loc=d3e48214-111002 + Details
Name: | us-gaap_LoansReceivableHeldForSaleNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=fmb_ConsumerRealEstateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |