XML 60 R48.htm IDEA: XBRL DOCUMENT
v3.25.1

Note 4 - Allowance for Credit Losses - Allowance by Impairment Methodology and Loans by Impairment Methodology (Details) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2025 | Mar. 31, 2024 | Dec. 31, 2024
Balance | $ 16,400 | $ 11,974 | $ 11,974
Charge-offs | (2,490) | (414) | (4,034)
Recoveries | 90 | 52 | 284
Provision for (recovery of) credit losses on loans | 735 | 991 |
Balance | 14,735 | 12,603 | 16,400
Individually evaluated | 1,609 |  | 3,079
Collectively evaluated | 13,126 |  |
Loans | 1,449,950 | 972,974 | 1,466,595
Individually evaluated | 4,808 | 8,011 | 6,971
Collectively evaluated | 1,445,142 | 964,963 | 1,459,624
Provision for credit losses on loans | 735 | 991 |
Collectively evaluated for impairment |  | 9,034 | 13,321
Individually evaluated |  | 3,569 |
Loans Before Business Acquisitions [Member] |  |  |
Provision for (recovery of) credit losses on loans |  |  | 3,961
Provision for credit losses on loans |  |  | 3,961
Financial Asset Acquired and No Credit Deterioration [Member] |  |  |
Loans | 573,562 |  | 603,046
Touchstone Bankshares, Inc [Member] |  |  |
Initial Allowance on PCD Touchstone loans |  |  | 386
Touchstone Bankshares, Inc [Member] | Financial Asset Acquired and No Credit Deterioration [Member] |  |  |
Provision for (recovery of) credit losses on loans |  |  | 3,829
Provision for credit losses on loans |  |  | 3,829
Real Estate 1 [Member] | Construction and Land Development [Member] |  |  |
Balance | 585 | 312 | 312
Charge-offs | (22) | (4) | (4)
Recoveries | 0 | 0 | 0
Provision for (recovery of) credit losses on loans | (7) | 47 |
Balance | 556 | 355 | 585
Individually evaluated | 0 |  | 0
Collectively evaluated | 556 |  |
Loans | 81,596 | 53,364 | 84,480
Individually evaluated | 75 | 37 | 50
Collectively evaluated | 81,521 | 53,327 | 84,430
Provision for credit losses on loans | (7) | 47 |
Collectively evaluated for impairment |  | 355 | 585
Individually evaluated |  | 0 |
Real Estate 1 [Member] | Construction and Land Development [Member] | Loans Before Business Acquisitions [Member] |  |  |
Provision for (recovery of) credit losses on loans |  |  | 148
Provision for credit losses on loans |  |  | 148
Real Estate 1 [Member] | Construction and Land Development [Member] | Touchstone Bankshares, Inc [Member] |  |  |
Initial Allowance on PCD Touchstone loans |  |  | 11
Real Estate 1 [Member] | Construction and Land Development [Member] | Touchstone Bankshares, Inc [Member] | Financial Asset Acquired and No Credit Deterioration [Member] |  |  |
Provision for (recovery of) credit losses on loans |  |  | 118
Provision for credit losses on loans |  |  | 118
Real Estate 1 [Member] | Secured by Multi-family Residential Properties [Member] |  |  |
Balance | 4,266 | 3,159 | 3,159
Charge-offs | (3) | (10) | (38)
Recoveries | 3 | 4 | 22
Provision for (recovery of) credit losses on loans | 972 | (396) |
Balance | 5,238 | 2,757 | 4,266
Individually evaluated | 0 |  | 0
Collectively evaluated | 5,238 |  |
Loans | 549,502 | 347,014 | 547,167
Individually evaluated | 2,071 | 772 | 2,148
Collectively evaluated | 547,431 | 346,242 | 545,019
Provision for credit losses on loans | 972 | (396) |
Collectively evaluated for impairment |  | 2,757 | 4,266
Individually evaluated |  | 0 |
Real Estate 1 [Member] | Secured by Multi-family Residential Properties [Member] | Loans Before Business Acquisitions [Member] |  |  |
Provision for (recovery of) credit losses on loans |  |  | (360)
Provision for credit losses on loans |  |  | (360)
Real Estate 1 [Member] | Secured by Multi-family Residential Properties [Member] | Touchstone Bankshares, Inc [Member] |  |  |
Initial Allowance on PCD Touchstone loans |  |  | 173
Real Estate 1 [Member] | Secured by Multi-family Residential Properties [Member] | Touchstone Bankshares, Inc [Member] | Financial Asset Acquired and No Credit Deterioration [Member] |  |  |
Provision for (recovery of) credit losses on loans |  |  | 1,310
Provision for credit losses on loans |  |  | 1,310
Real Estate 1 [Member] | Other Real Estate Loans [Member] |  |  |
Balance | 7,462 | 4,698 | 4,698
Charge-offs | 0 | 0 | 0
Recoveries | 1 | 1 | 3
Provision for (recovery of) credit losses on loans | (1,755) | 225 |
Balance | 5,708 | 4,924 | 7,462
Individually evaluated | 0 |  | 0
Collectively evaluated | 5,708 |  |
Loans | 665,682 | 445,085 | 672,162
Individually evaluated | 0 | 0 | 0
Collectively evaluated | 665,682 | 445,085 | 672,162
Provision for credit losses on loans | (1,755) | 225 |
Collectively evaluated for impairment |  | 4,924 | 7,462
Individually evaluated |  | 0 |
Real Estate 1 [Member] | Other Real Estate Loans [Member] | Loans Before Business Acquisitions [Member] |  |  |
Provision for (recovery of) credit losses on loans |  |  | 1,190
Provision for credit losses on loans |  |  | 1,190
Real Estate 1 [Member] | Other Real Estate Loans [Member] | Touchstone Bankshares, Inc [Member] |  |  |
Initial Allowance on PCD Touchstone loans |  |  | 201
Real Estate 1 [Member] | Other Real Estate Loans [Member] | Touchstone Bankshares, Inc [Member] | Financial Asset Acquired and No Credit Deterioration [Member] |  |  |
Provision for (recovery of) credit losses on loans |  |  | 1,370
Provision for credit losses on loans |  |  | 1,370
Commercial and Industrial Loans [Member] |  |  |
Balance | 3,927 | 3,706 | 3,706
Charge-offs | (2,343) | (317) | (3,699)
Recoveries | 33 | 6 | 111
Provision for (recovery of) credit losses on loans | 1,388 | 1,098 |
Balance | 3,005 | 4,493 | 3,927
Individually evaluated | 1,609 |  | 3,079
Collectively evaluated | 1,396 |  |
Loans | 132,396 | 113,562 | 141,333
Individually evaluated | 2,662 | 7,202 | 4,773
Collectively evaluated | 129,734 | 106,360 | 136,560
Provision for credit losses on loans | 1,388 | 1,098 |
Collectively evaluated for impairment |  | 924 | 848
Individually evaluated |  | 3,569 |
Commercial and Industrial Loans [Member] | Loans Before Business Acquisitions [Member] |  |  |
Provision for (recovery of) credit losses on loans |  |  | 3,665
Provision for credit losses on loans |  |  | 3,665
Commercial and Industrial Loans [Member] | Touchstone Bankshares, Inc [Member] |  |  |
Initial Allowance on PCD Touchstone loans |  |  | 1
Commercial and Industrial Loans [Member] | Touchstone Bankshares, Inc [Member] | Financial Asset Acquired and No Credit Deterioration [Member] |  |  |
Provision for (recovery of) credit losses on loans |  |  | 143
Provision for credit losses on loans |  |  | 143
Consumer and Other Loans [Member] |  |  |
Balance | 160 | 99 | 99
Charge-offs | (122) | (83) | (293)
Recoveries | 53 | 41 | 148
Provision for (recovery of) credit losses on loans | 137 | 17 |
Balance | 228 | 74 | 160
Individually evaluated | 0 |  | 0
Collectively evaluated | 228 |  |
Loans | 20,774 | 13,949 | 21,453
Individually evaluated | 0 | 0 | 0
Collectively evaluated | 20,774 | 13,949 | 21,453
Provision for credit losses on loans | $ 137 | 17 |
Collectively evaluated for impairment |  | 74 | 160
Individually evaluated |  | $ 0 |
Consumer and Other Loans [Member] | Loans Before Business Acquisitions [Member] |  |  |
Provision for (recovery of) credit losses on loans |  |  | (682)
Provision for credit losses on loans |  |  | (682)
Consumer and Other Loans [Member] | Touchstone Bankshares, Inc [Member] |  |  |
Initial Allowance on PCD Touchstone loans |  |  | 0
Consumer and Other Loans [Member] | Touchstone Bankshares, Inc [Member] | Financial Asset Acquired and No Credit Deterioration [Member] |  |  |
Provision for (recovery of) credit losses on loans |  |  | 888
Provision for credit losses on loans |  |  | $ 888

X
- Definition Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment. + References No definition available. + Details
Name: | fxnc_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment
Namespace Prefix: | fxnc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment. + References No definition available. + Details
Name: | fxnc_FinancingReceivablesAllowanceForCreditLossesCollectivelyEvaluatedForImpairment
Namespace Prefix: | fxnc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of increase in allowance for credit loss on financing receivable purchased with credit deterioration. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-13 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossPurchasedWithCreditDeteriorationIncrease
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-13 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-13 Reference 3: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 11B -Subparagraph (c)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481962/310-10-50-11B Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-K (SK) -Number 229 -Section 1405 -Paragraph c -Publisher SEC Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-K (SK) -Number 229 -Section 1405 -Paragraph a -Subparagraph (1) -Publisher SEC Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-K (SK) -Number 229 -Section 1405 -Paragraph a -Subparagraph (3) -Publisher SEC Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(4)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479344/326-20-45-1 Reference 9: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(7)(2)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLosses
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of allowance for credit loss on financing receivable evaluated on collective basis. Excludes financing receivable evaluated on individual basis. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 4 -Subparagraph (SAB Topic 6.L.5.a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480418/310-10-S99-4 Reference 2: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 11B -Subparagraph (g) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481962/310-10-50-11B Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 30 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479391/326-20-30-2 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of allowance for credit loss on financing receivable evaluated on individual basis. Excludes financing receivable evaluated on collective basis. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 4 -Subparagraph (SAB Topic 6.L.5.a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480418/310-10-S99-4 Reference 2: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 11B -Subparagraph (g) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481962/310-10-50-11B Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 30 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479391/326-20-30-2 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of increase in allowance for credit loss on financing receivable from recovery. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-13 Reference 2: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 11B -Subparagraph (c)(4) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481962/310-10-50-11B Reference 3: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-79 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of writeoff of financing receivable, charged against allowance for credit loss. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-13 Reference 2: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 11B -Subparagraph (c)(3) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481962/310-10-50-11B Reference 3: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-79 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-6 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of financing receivable collectively evaluated for credit loss. Excludes financing receivable individually evaluated for credit loss. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 4 -Subparagraph (SAB Topic 6.L.5.a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480418/310-10-S99-4 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 11C -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481962/310-10-50-11C + Details
Name: | us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of financing receivable individually evaluated for credit loss. Excludes financing receivable collectively evaluated for credit loss. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 4 -Subparagraph (SAB Topic 6.L.5.a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480418/310-10-S99-4 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 11C -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481962/310-10-50-11C + Details
Name: | us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost, before allowance for credit loss, of financing receivable. Excludes financing receivable covered under loss sharing agreement and net investment in lease. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479344/326-20-45-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 1A -Publisher FASB -URI https://asc.fasb.org/1943274/2147482736/825-10-45-1A Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 948 -SubTopic 310 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477011/948-310-45-1 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 13 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481990/310-10-45-13 Reference 5: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 7A -Publisher FASB -URI https://asc.fasb.org/1943274/2147481962/310-10-50-7A Reference 6: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 29 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481962/310-10-50-29 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-K (SK) -Number 229 -Section 1405 -Paragraph a -Subparagraph (1) -Publisher SEC Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-K (SK) -Number 229 -Section 1405 -Paragraph a -Subparagraph (2) -Publisher SEC Reference 9: http://www.xbrl.org/2009/role/commonPracticeRef -Name Regulation S-K (SK) -Number 229 -Section 1404 -Paragraph a -Publisher SEC Reference 10: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 80 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-80 Reference 11: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-79 Reference 12: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(3)(b)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 13: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 14 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-14 Reference 14: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-5 + Details
Name: | us-gaap_NotesReceivableGross
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of credit loss expense (reversal of expense) for financing receivable. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-13 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 220 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 22 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147476148/220-40-50-22 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 220 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04(11)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478524/942-220-S99-1 + Details
Name: | us-gaap_ProvisionForLoanLossesExpensed
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=fxnc_LoansBeforeBusinessAcquisitionsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CreditLossStatusAxis=us-gaap_FinancialAssetAcquiredAndNoCreditDeteriorationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=fxnc_TouchstoneBanksharesIncMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=fxnc_RealEstate1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=fxnc_ConstructionAndLandDevelopmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=fxnc_SecuredByMultifamilyResidentialPropertiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=fxnc_OtherRealEstateLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=fxnc_CommercialAndIndustrialLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=fxnc_ConsumerAndOtherLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |