XML 64 R51.htm IDEA: XBRL DOCUMENT v2.4.0.6

Earnings per Common Share (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Earnings per Common Share (Textual) [Abstract]
Average number of common shares outstanding basic and diluted	4,901,464	2,955,649	3,623,191	2,952,568

X

- Details

Name:	fxnc_EarningsPerCommonShareTextualAbstract
Namespace Prefix:	fxnc_
Data Type:	xbrli:stringItemType
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