XML 39 R53.htm IDEA: XBRL DOCUMENT
v2.4.0.6

Earnings per Common Share (Details) | 3 Months Ended
--- | ---
Mar. 31, 2013 | Mar. 31, 2012
Earnings per Common Share (Textual) [Abstract] |  |
Number of Common Stock Having Dilutive Effect | 0 |
Average number of common shares outstanding basic and diluted | 4,901,464 | 2,955,649

X
- Details
Name: | fxnc_EarningsPerCommonShareTextualAbstract
Namespace Prefix: | fxnc_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of common stock having dilutive effect. + References No definition available. + Details
Name: | fxnc_NumberOfCommonStockHavingDilutiveEffect
Namespace Prefix: | fxnc_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Average number of shares or units issued and outstanding that are used in calculating basic and diluted earnings per share (EPS). + References No definition available. + Details
Name: | us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration