XML 109 R94.htm IDEA: XBRL DOCUMENT
v3.20.4

Employee Benefit Plans - Additional Information (Detail) | 12 Months Ended
--- | ---
Dec. 31, 2020 USD ($) Employee shares | Dec. 31, 2019 USD ($) Employee shares | Dec. 31, 2018 USD ($) Employee shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Minimum percentage of eligible compensation on a pre-tax basis for eligible employees to save | 1.00% |  |
Employee contribution matching percentage | 50.00% |  |
Percentage of total eligible compensation, contribution by Bank, maximum limit | 4.00% |  |
Vesting percentage in participant's deferral contributions and employer matching contributions | 100.00% |  |
Vesting period | 6 years |  |
Employer matching contribution and the discretionary contribution | $ | $ 1,000,000.0 | $ 1,200,000 | $ 1,100,000
Restricted stock awards, shares issued | 37,382 | 38,100 | 33,000
Awards grants originated in 2016, 2017 and 2018 [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Number of employees, received the stock | Employee |  | 3 |
Four employees received shares from awards granted due to retirement |  | 14,300 |
Awards grants originated in 2019, 2018 and 2017 [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Number of employees, received the stock | Employee | 1 |  |
Number of shares vested | 1,050 |  |
Awards grants originated in 2017, 2018 and 2019 and 2020 [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Number of employees, received the stock | Employee | 8 |  |
Number of shares vested | 10,890 |  |
Restricted Stock Awards [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Vesting period | 3 years |  |
Restricted stock awards, shares issued | 37,382 | 38,100 | 33,000
Stock issued to number of employees | Employee | 92 | 94 | 80
Shares vest under the plan | 100.00% | 100.00% | 100.00%
Shares forfeited due to employee termination | 2,175 | 3,220 | 2,620
Number of shares vested | 35,431 | 40,370 | 28,790
Number of employees, received the stock | Employee | 57 | 63 | 56
Number of shares vested | 10,890 | 14,300 |
Compensation expense | $ | $ 1,000,000.0 | $ 1,100 | $ 745,000
Unrecognized compensation cost related to the nonvested portion of restricted stock awards under the plan | $ | $ 1,300,000 |  |
Unrecognized compensation cost related to the nonvested portion of restricted stock awards under the plan, period for recognition | 3 years |  |
Restricted Stock Awards [Member] | 2014 [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Number of shares vested |  |  | 28,790
Restricted Stock Awards [Member] | 2019 [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Number of shares vested | 1,600 |  |
Number of employees, received the stock | Employee | 3 |  |
Restricted Stock Awards [Member] | 2015 [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Number of shares vested |  | 26,070 |
Restricted Stock Awards [Member] | 2017 [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Number of shares vested | 21,340 |  |
Number of employees, received the stock | Employee | 53 |  |
Restricted Stock Awards [Member] | Immediate Vesting [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Number of employees, received the stock | Employee | 1 |  |
Number of shares vested | 551,000 |  |

X
- Definition Minimum percentage of eligible compensation on pre tax basis for eligible employees to save. + References No definition available. + Details
Name: | fmao_MinimumPercentageOfEligibleCompensationOnPreTaxBasisForEligibleEmployeesToSave
Namespace Prefix: | fmao_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of awards granted to four employees on retirement. + References No definition available. + Details
Name: | fmao_NumberOfAwardsGrantedToFourEmployeesOnRetirement
Namespace Prefix: | fmao_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of awards granted to one employee on retirement. + References No definition available. + Details
Name: | fmao_NumberOfAwardsGrantedToOneEmployeeOnRetirement
Namespace Prefix: | fmao_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Share based compensation arrangement by share based payment award equity instruments other than options share vested percentage. + References No definition available. + Details
Name: | fmao_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsShareVestedPercentage
Namespace Prefix: | fmao_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Share based compensation arrangement by share based payment award number of employee share issued. + References No definition available. + Details
Name: | fmao_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfEmployeeShareIssued
Namespace Prefix: | fmao_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Share based compensation arrangement by share based payment award number of employees. + References No definition available. + Details
Name: | fmao_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfEmployees
Namespace Prefix: | fmao_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of expense for award under share-based payment arrangement. Excludes amount capitalized. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5047-113901 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 14.F) -URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(1)(i) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
Name: | us-gaap_AllocatedShareBasedCompensationExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of discretionary contributions made by an employer to a defined contribution plan. + References No definition available. + Details
Name: | us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan. + References No definition available. + Details
Name: | us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of employer's matching contributions to a defined contribution plan that vests in a given year. + References No definition available. + Details
Name: | us-gaap_DefinedContributionPlanEmployersMatchingContributionAnnualVestingPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Maximum percentage of employee gross pay the employee may contribute to a defined contribution plan. + References No definition available. + Details
Name: | us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (i) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
Name: | us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of cost to be recognized for nonvested award under share-based payment arrangement. Excludes share and unit options. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (i) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
Name: | us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(iv)(3) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(iii)(2) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

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 No definition available. + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Total number of shares issued during the period, including shares forfeited, as a result of Restricted Stock Awards. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770 + Details
Name: | us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardGross
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_AwardDateAxis=fmao_AwardGrantsOriginatedInPeriodOneMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardDateAxis=fmao_AwardGrantsOriginatedInPeriodThreeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardDateAxis=fmao_AwardGrantsOriginatedInPeriodTwoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardTypeAxis=us-gaap_RestrictedStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardDateAxis=fmao_YearTwoThousandFourteenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardDateAxis=fmao_YearTwoThousandNineteenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardDateAxis=fmao_YearTwoThousandFifteenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardDateAxis=fmao_YearTwoThousandSeventeenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardDateAxis=fmao_ImmediateVestingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |