Note 4 - Loans and Allowance for Loan Losses (Detail) - TDR Loan Modifications (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Residential real estate
Troubled Debt Restructurings	$ 12,158	$ 9,355
Performing to Modified Terms [Member] | Residential Real Estate Loans [Member] | Rate Reduction [Member]
Residential real estate
Troubled Debt Restructurings	420	420
Performing to Modified Terms [Member] | Commercial Real Estate Owner Occupied [Member] | Interest Only Payments [Member]
Residential real estate
Troubled Debt Restructurings		680
Performing to Modified Terms [Member] | Commercial Real Estate Owner Occupied [Member] | Rate Reduction [Member]
Residential real estate
Troubled Debt Restructurings		449
Performing to Modified Terms [Member] | Commercial Real Estate Owner Occupied [Member] | Maturity Extension at Lower Stated Rate Than Market Rate [Member]
Residential real estate
Troubled Debt Restructurings	199	219
Performing to Modified Terms [Member] | Commercial Real Estate Owner Occupied [Member] | Reduction of Principal and Interest Payments [Member]
Residential real estate
Troubled Debt Restructurings	4,244
Performing to Modified Terms [Member] | Commercial Real Estate Nonowner Occupied [Member] | Interest Only Payments [Member]
Residential real estate
Troubled Debt Restructurings	3,899	6,296
Performing to Modified Terms [Member] | Reduction of Principal and Interest Payments [Member] | Commercial Real Estate Nonowner Occupied [Member]
Residential real estate
Troubled Debt Restructurings	676
Performing to Modified Terms [Member] | Construction [Member] | Interest Only Payments [Member]
Residential real estate
Troubled Debt Restructurings		674
Performing to Modified Terms [Member] | Commercial and Industrial [Member] | Interest Only Payments [Member]
Residential real estate
Troubled Debt Restructurings		334
Performing to Modified Terms [Member]
Residential real estate
Troubled Debt Restructurings	9,438	9,072
Not Performing to Modified Terms [Member] | Residential Real Estate Loans [Member] | Interest Only Payments [Member]
Residential real estate
Troubled Debt Restructurings	252	283
Not Performing to Modified Terms [Member] | Commercial Real Estate Owner Occupied [Member] | Interest Only Payments [Member]
Residential real estate
Troubled Debt Restructurings	675
Not Performing to Modified Terms [Member] | Commercial Real Estate Owner Occupied [Member] | Rate Reduction [Member]
Residential real estate
Troubled Debt Restructurings	440
Not Performing to Modified Terms [Member] | Commercial Real Estate Nonowner Occupied [Member] | Interest Only Payments [Member]
Residential real estate
Troubled Debt Restructurings	958
Not Performing to Modified Terms [Member] | Construction [Member] | Interest Only Payments [Member]
Residential real estate
Troubled Debt Restructurings	395
Not Performing to Modified Terms [Member]
Residential real estate
Troubled Debt Restructurings	2,720	283
Residential Real Estate Loans [Member] | Interest Only Payments [Member]
Residential real estate
Troubled Debt Restructurings	252	283
Residential Real Estate Loans [Member] | Rate Reduction [Member]
Residential real estate
Troubled Debt Restructurings	420	420
Commercial Real Estate Owner Occupied [Member] | Interest Only Payments [Member]
Residential real estate
Troubled Debt Restructurings	675	680
Commercial Real Estate Owner Occupied [Member] | Rate Reduction [Member]
Residential real estate
Troubled Debt Restructurings	440	449
Commercial Real Estate Owner Occupied [Member] | Maturity Extension at Lower Stated Rate Than Market Rate [Member]
Residential real estate
Troubled Debt Restructurings	199	219
Commercial Real Estate Owner Occupied [Member] | Reduction of Principal and Interest Payments [Member]
Residential real estate
Troubled Debt Restructurings	4,244
Commercial Real Estate Nonowner Occupied [Member] | Interest Only Payments [Member]
Residential real estate
Troubled Debt Restructurings	4,857	6,296
Reduction of Principal and Interest Payments [Member] | Commercial Real Estate Nonowner Occupied [Member]
Residential real estate
Troubled Debt Restructurings	676
Construction [Member] | Interest Only Payments [Member]
Residential real estate
Troubled Debt Restructurings	395	674
Commercial and Industrial [Member] | Interest Only Payments [Member]
Residential real estate
Troubled Debt Restructurings		$ 334