Document And Entity Information	3 Months Ended
	Mar. 31, 2012	May 09, 2012
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2012
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	Q1
Entity Registrant Name	CARDINAL BANKSHARES CORP
Entity Central Index Key	0001022759
Current Fiscal Year End Date	--12-31
Entity Filer Category	Smaller Reporting Company
Entity Common Stock, Shares Outstanding		1,535,733