Note 4. Loans and Allowance for Loan Losses (Detail) - Risk Category of Commercial Loans (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Commercial Loans	$ 229,891	$ 252,655
Pass [Member] | Commercial Real Estate Owner Occupied [Member]
Commercial Loans	85,829	103,743
Pass [Member] | Commercial Real Estate Nonowner Occupied [Member]
Commercial Loans	33,931	30,375
Pass [Member] | Construction [Member]
Commercial Loans	22,166	19,519
Pass [Member] | Commercial and Industrial [Member]
Commercial Loans	38,809	36,633
Pass [Member]
Commercial Loans	180,735	190,270
Criticized [Member] | Commercial Real Estate Owner Occupied [Member]
Commercial Loans	13,152	15,030
Criticized [Member] | Commercial Real Estate Nonowner Occupied [Member]
Commercial Loans	8,448	12,815
Criticized [Member] | Commercial and Industrial [Member]
Commercial Loans	75	3,250
Criticized [Member]
Commercial Loans	21,675	31,095
Classified [Member] | Commercial Real Estate Owner Occupied [Member]
Commercial Loans	11,290	13,530
Classified [Member] | Commercial Real Estate Nonowner Occupied [Member]
Commercial Loans	7,519	10,491
Classified [Member] | Construction [Member]
Commercial Loans	1,574	1,952
Classified [Member] | Commercial and Industrial [Member]
Commercial Loans	7,098	5,317
Classified [Member]
Commercial Loans	27,481	31,290
Commercial Real Estate Owner Occupied [Member]
Commercial Loans	110,271	132,303
Commercial Real Estate Nonowner Occupied [Member]
Commercial Loans	49,898	53,681
Construction [Member]
Commercial Loans	23,740	21,471
Commercial and Industrial [Member]
Commercial Loans	$ 45,982	$ 45,200