XML 75 R63.htm IDEA: XBRL DOCUMENT
v3.21.1

Note 12 - Fair Value Measurements - Quantitative Information About Level 3 Fair Value Measurements (Details) - Impaired Loans [Member] - Fair Value, Nonrecurring [Member] $ in Thousands | Mar. 31, 2021 USD ($) | Dec. 31, 2020 USD ($)
--- | --- | ---
Assets, Fair Value |  | $ 3,630 | $ 3,595
Fair Value, Inputs, Level 3 [Member] |  |  |
Assets, Fair Value |  | $ 3,630 | $ 3,595
Fair Value, Inputs, Level 3 [Member] | Measurement Input, Cost to Sell [Member] |  |  |
Measurement input | [1] | 0.1 | 0.1
Fair Value, Inputs, Level 3 [Member] | Measurement Input, Discount Rate [Member] |  |  |
Measurement input | [1] | 0.065 | 0.065
Fair Value, Inputs, Level 3 [Member] | Valuation Technique, Property Appraisals [Member] |  |  |
Assets, Fair Value |  | $ 2,205 | $ 2,205
Fair Value, Inputs, Level 3 [Member] | Valuation Technique, Discounted Cash Flow [Member] |  |  |
Assets, Fair Value |  | $ 1,425 | $ 1,390
[1] | Unobservable inputs were weighted by the relative fair value of the instruments

X
- Definition Value of input used to measure impaired loans. + References No definition available. + Details
Name: | fxnc_ImpairedLoansMeasurementInput
Namespace Prefix: | fxnc_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | instant

X
- Definition Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 + Details
Name: | us-gaap_AssetsFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=fxnc_ImpairedLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsNonrecurringMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputCostToSellMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputDiscountRateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ValuationTechniqueAxis=fxnc_ValuationTechniquePropertyAppraisalsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ValuationTechniqueAxis=us-gaap_ValuationTechniqueDiscountedCashFlowMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |