Document And Entity Information	6 Months Ended
Jun. 30, 2011	Dec. 05, 2011
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	true
Amendment Description	Cardinal Bankshares Corporation (the "Company") files this Amendment No. 1 on Form 10-Q/A to amend its Quarterly Report on Form 10-Q for the quarter ended June 30, 2011 that was originally filed with Securities and Exchange Commission on August 12, 2011 (the "Original Filing".) We file this Form 10-Q/A to correct the inadvertent omission of the additional required disclosures regarding loans and the allowance for loan losses contained in Part I, Item 1, Note 2 of the Consolidated Financial Statements in the Original Filing. The appropriate information is set forth in the revised tables included in this Form 10-Q/A. Other than the correction of minor typographical errors, no other changes have been made to the Form 10-Q. This Form 10-Q/A does not reflect events that may have occurred subsequent to the Original Filing and does not modify or update in any way other disclosures made in the Form 10-Q. Pursuant to Exchange Act Rule 12b-5, new certifications by the Company's principal executive officer and principal financial officer are filed or furnished with this Form 10-Q/A as Exhibits 31.1, 31.2, and 32.1.
Document Period End Date	Jun. 30, 2011
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	Q2
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

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