XML 20 R56.htm IDEA: XBRL DOCUMENT
v2.4.0.8

Fair Value Measurements - Summary of Assets Measured at Fair Value on a Nonrecurring Basis (Detail) (Fair Value, Measurements, Nonrecurring [Member], USD $) In Thousands, unless otherwise specified | Sep. 30, 2013 | Dec. 31, 2012
--- | --- | ---
Assets |  |
Impaired loans, net | $ 3,671 | $ 7,944
Other real estate owned, net | 3,833 | 5,590
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] |  |
Assets |  |
Impaired loans, net |  |
Other real estate owned, net |  |
Significant Other Observable Inputs (Level 2) [Member] |  |
Assets |  |
Impaired loans, net |  |
Other real estate owned, net |  |
Significant Unobservable Inputs (Level 3) [Member] |  |
Assets |  |
Impaired loans, net | 3,671 | 7,944
Other real estate owned, net | $ 3,833 | $ 5,590

X
- Definition Impaired loans fair value disclosures. + References No definition available. + Details
Name: | fxnc_ImpairedLoansFairValueDisclosures
Namespace Prefix: | fxnc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Other real estate fair value disclosure. + References No definition available. + Details
Name: | fxnc_OtherRealEstateFairValueDisclosure
Namespace Prefix: | fxnc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration