Note 4. Loans and Allowance for Loan Losses (Detail) (USD $)	3 Months Ended	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2012	Dec. 31, 2011
Change in Troubled Debt Restructurings		23.10%
Percentage of Loan Portfolio	80.00%	80.00%
Impaired Financing Receivable, Related Allowance	$ 1,845,000	$ 1,845,000	$ 655,000
Other Commitment	94	94	81
Minimum Loan Balance for Loans Evaluated by Risk Categories	500	500
Troubled Debt Restructurings [Member]
Increase (Decrease) in Other Loans		2,159,000
Financing Receivable, Allowance for Credit Losses, Write-downs	4,266,000
Impaired Financing Receivable, Related Allowance	$ 1,553,000	$ 1,553,000	$ 655,000
Commercial and Industrial [Member]
Financing Receivable, Modifications, Number of Contracts	1	1
Troubled Debt Restructurings Performing According to Modified Terms [Member]
Percentage of Loan Portfolio			97.00%
Unsecured [Member]
Percentage of Loan Portfolio	4.12%	4.12%	3.98%