XML 80 R64.htm IDEA: XBRL DOCUMENT
v3.20.4

Securities Available for Sale (Details Textual) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2020 USD ($) Securities | Dec. 31, 2019 USD ($) | Dec. 31, 2018 USD ($)
Schedule Of Available For Sale Securities [Line Items] |  |  |  |
Tax provision related to net realized gain | [1] | $ (90) | $ (2) | $ 59
Pledged to secure public deposits and repurchase agreements and Pledge to qualify carrying amount of securities |  | $ 371,000 | 253,000 |
Number of securities not more than 10% of stockholder equities | Securities |  | 0 |  |
Equity securities |  | $ 6,881 | 7,909 |
Number of securities | Securities |  | 671 |  |
Number of securities on unrealized loss position | Securities |  | 45 |  |
Small Business Investment Company Partnership Investments |  |  |  |
Schedule Of Available For Sale Securities [Line Items] |  |  |  |
Equity securities |  | $ 6,300 |  |
Local and Regional Bank Holdings and Other Miscellaneous Equity Funds |  |  |  |
Schedule Of Available For Sale Securities [Line Items] |  |  |  |
Equity securities |  | 538 |  |
Farmers Trust Company |  |  |  |
Schedule Of Available For Sale Securities [Line Items] |  |  |  |
Pledged to secure public deposits and repurchase agreements and Pledge to qualify carrying amount of securities |  | $ 100 | $ 100 |
[1] | Pre-tax reclassification adjustments relating to available-for-sale securities are reported in security gains and the tax impact is included in income tax expense on the consolidated statements of income.

X
- Definition Number of securities. + References No definition available. + Details
Name: | fmnb_NumberOfSecurities
Namespace Prefix: | fmnb_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of securities on unrealized loss position. + References No definition available. + Details
Name: | fmnb_NumberOfSecuritiesOnUnrealizedLossPosition
Namespace Prefix: | fmnb_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of securities present more than specified percentage. + References No definition available. + Details
Name: | fmnb_NumberOfSecuritiesPresentMoreThanSpecifiedPercentage
Namespace Prefix: | fmnb_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of restricted investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 30 -Section 50 -Paragraph 1A -Subparagraph (b)(1)(i) -URI http://asc.fasb.org/extlink&oid=109249958&loc=SL6224234-111729 + Details
Name: | us-gaap_DebtSecuritiesAvailableForSaleRestricted
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 45 -Paragraph 1A -URI http://asc.fasb.org/extlink&oid=99377092&loc=SL75136599-209740 + Details
Name: | us-gaap_EquitySecuritiesFvNi
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of tax expense (benefit) of reclassification adjustment from accumulated other comprehensive income for unrealized gain (loss) realized upon the sale of available-for-sale securities. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=121641772&loc=d3e640-108580 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27357-111563 + Details
Name: | us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
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_ScheduleOfAvailableForSaleSecuritiesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_InvestmentTypeAxis=fmnb_SmallBusinessInvestmentCompanyPartnershipInvestmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=fmnb_LocalAndRegionalBankHoldingsAndOtherMiscellaneousEquityFundsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=fmnb_FarmersTrustCompanyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |