XML 48 R36.htm IDEA: XBRL DOCUMENT
v3.7.0.1

Securities - Summary of Amortized Costs and Fair Values of Securities (Detail) - USD ($) $ in Thousands | Mar. 31, 2017 | Dec. 31, 2016
--- | --- | ---
Schedule Of Available For Sale And Held To Maturity Securities [Line Items] |  |  |
Available-for-sale Securities, Debt and Equity, Amortized Cost Basis, Total | $ 92,634 | $ 96,106 |
Securities available for sale, Gross Unrealized Gains | 394 | 333 |
Securities available for sale, Gross Unrealized (Losses) | (1,121) | (1,637) |
Securities available for sale, Fair Value | 91,907 | 94,802 | [1]
Securities held to maturity, Amortized Cost | 51,999 | 53,398 |
Securities held to maturity, Gross Unrealized Gains | 69 | 19 |
Securities held to maturity, Gross Unrealized (Losses) | (460) | (708) |
Securities held to maturity, Fair Value | 51,608 | 52,709 | [1]
Total securities, Amortized Cost | 144,633 | 149,504 |
Total securities, Gross Unrealized Gains | 463 | 352 |
Total securities, Gross Unrealized (Losses) | (1,581) | (2,345) |
Total securities, Fair Value | 143,515 | 147,511 |
U.S. Agency and Mortgage-Backed Securities [Member] |  |  |
Schedule Of Available For Sale And Held To Maturity Securities [Line Items] |  |  |
Available-for-sale Securities, Debt and Equity, Amortized Cost Basis, Total | 78,026 | 81,451 |
Securities available for sale, Gross Unrealized Gains | 186 | 177 |
Securities available for sale, Gross Unrealized (Losses) | (985) | (1,457) |
Securities available for sale, Fair Value | 77,227 | 80,171 |
Securities held to maturity, Amortized Cost | 35,888 | 37,269 |
Securities held to maturity, Gross Unrealized Gains | 20 | 1 |
Securities held to maturity, Gross Unrealized (Losses) | (351) | (483) |
Securities held to maturity, Fair Value | 35,557 | 36,787 |
Obligations of States and Political Subdivisions [Member] |  |  |
Schedule Of Available For Sale And Held To Maturity Securities [Line Items] |  |  |
Available-for-sale Securities, Debt and Equity, Amortized Cost Basis, Total | 14,607 | 14,654 |
Securities available for sale, Gross Unrealized Gains | 198 | 146 |
Securities available for sale, Gross Unrealized (Losses) | (136) | (180) |
Securities available for sale, Fair Value | 14,669 | 14,620 |
Securities held to maturity, Amortized Cost | 14,611 | 14,629 |
Securities held to maturity, Gross Unrealized Gains | 49 | 18 |
Securities held to maturity, Gross Unrealized (Losses) | (93) | (211) |
Securities held to maturity, Fair Value | 14,567 | 14,436 |
Corporate Equity Securities [Member] |  |  |
Schedule Of Available For Sale And Held To Maturity Securities [Line Items] |  |  |
Available-for-sale Securities, Debt and Equity, Amortized Cost Basis, Total | 1 | 1 |
Securities available for sale, Gross Unrealized Gains | 10 | 10 |
Securities available for sale, Fair Value | 11 | 11 |
Corporate Debt Securities [Member] |  |  |
Schedule Of Available For Sale And Held To Maturity Securities [Line Items] |  |  |
Securities held to maturity, Amortized Cost | 1,500 | 1,500 |
Securities held to maturity, Gross Unrealized (Losses) | (16) | (14) |
Securities held to maturity, Fair Value | $ 1,484 | $ 1,486 |
[1] | Derived from audited consolidated financial statements.

X
- Definition Available for sale and held to maturity securities accumulated gross unrealized loss. + References No definition available. + Details
Name: | fxnc_AvailableForSaleAndHeldToMaturitySecuritiesAccumulatedGrossUnrealizedLoss
Namespace Prefix: | fxnc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Available for sale securities and held to maturity securities accumulated gross unrealized gain. + References No definition available. + Details
Name: | fxnc_AvailableForSaleSecuritiesAndHeldToMaturitySecuritiesAccumulatedGrossUnrealizedGain
Namespace Prefix: | fxnc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Available For Sale Securities And Held To Maturity Securities Amortized Cost + References No definition available. + Details
Name: | fxnc_AvailableForSaleSecuritiesAndHeldToMaturitySecuritiesAmortizedCost
Namespace Prefix: | fxnc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Schedule Of Available For Sale And Held To Maturity Securities [Line Items] + References No definition available. + Details
Name: | fxnc_ScheduleOfAvailableForSaleAndHeldToMaturitySecuritiesLineItems
Namespace Prefix: | fxnc_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 25 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=65884222&loc=d3e22054-111558 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=66010992&loc=d3e26610-111562 + Details
Name: | us-gaap_AvailableForSaleSecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27161-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedGainBeforeTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27161-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.2) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_AvailableForSaleSecuritiesAmortizedCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of debt and equity financial instruments classified as either held-to-maturity or available-for-sale. + References No definition available. + Details
Name: | us-gaap_AvailableForSaleSecuritiesAndHeldToMaturitySecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of accumulated unrealized gain on investments in debt securities classified as held-to-maturity. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563 + Details
Name: | us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of accumulated unrealized loss on investments in debt securities classified as held-to-maturity. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563 + Details
Name: | us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount before other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity. + References No definition available. + Details
Name: | us-gaap_HeldToMaturitySecuritiesAmortizedCostBeforeOtherThanTemporaryImpairment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value of investments in debt securities classified as held-to-maturity. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (f) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563 + Details
Name: | us-gaap_HeldToMaturitySecuritiesFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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

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

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

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