Note 4 - Loans and Allowance for Loan Losses - TDR Loan Modifications (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Troubled Debt Restructuring	$ 16,318	$ 16,043
Interest Only Payments [Member] | Commercial Real Estate Owner Occupied [Member]
Troubled Debt Restructuring	231
Interest Only Payments [Member] | Commercial Real Estate Nonowner Occupied [Member]
Troubled Debt Restructuring	2,742
Interest Rate Below Market Reduction [Member] | Commercial Real Estate Nonowner Occupied [Member]
Troubled Debt Restructuring	572
Contractual Interest Rate Reduction [Member] | Commercial Real Estate Owner Occupied [Member]
Troubled Debt Restructuring	232
Contractual Interest Rate Reduction [Member] | Commercial Real Estate Nonowner Occupied [Member]
Troubled Debt Restructuring	381
Reduction of Principal and Interest Payments [Member] | Commercial Real Estate Owner Occupied [Member]
Troubled Debt Restructuring	573
Extended Maturity [Member] | Commercial Real Estate Owner Occupied [Member]
Troubled Debt Restructuring	1,560
Residential Portfolio Segment [Member] | Interest Only Payments [Member]
Troubled Debt Restructuring	711	717
Residential Portfolio Segment [Member] | Interest Rate Below Market Reduction [Member]
Troubled Debt Restructuring	204
Commercial Real Estate Portfolio Segment [Member] | Interest Only Payments [Member] | Commercial Real Estate Owner Occupied [Member]
Troubled Debt Restructuring		284
Commercial Real Estate Portfolio Segment [Member] | Interest Only Payments [Member] | Commercial Real Estate Nonowner Occupied [Member]
Troubled Debt Restructuring		2,810
Commercial Real Estate Portfolio Segment [Member] | Interest Rate Below Market Reduction [Member] | Commercial Real Estate Owner Occupied [Member]
Troubled Debt Restructuring		574
Commercial Real Estate Portfolio Segment [Member] | Contractual Interest Rate Reduction [Member] | Commercial Real Estate Owner Occupied [Member]
Troubled Debt Restructuring		232
Commercial Real Estate Portfolio Segment [Member] | Contractual Interest Rate Reduction [Member] | Commercial Real Estate Nonowner Occupied [Member]
Troubled Debt Restructuring		384
Commercial Real Estate Portfolio Segment [Member] | Reduction of Principal and Interest Payments [Member] | Commercial Real Estate Owner Occupied [Member]
Troubled Debt Restructuring		579
Commercial Real Estate Portfolio Segment [Member] | Extended Maturity [Member] | Commercial Real Estate Owner Occupied [Member]
Troubled Debt Restructuring		1,582
Commercial and Industrial Portfolio Segment [Member] | Interest Only Payments [Member]
Troubled Debt Restructuring		8,074
Commercial and Industrial Portfolio Segment [Member] | Interest Only Payments [Member] | Commercial Real Estate Nonowner Occupied [Member]
Troubled Debt Restructuring	8,512
Commercial and Industrial Portfolio Segment [Member] | Interest Rate Below Market Reduction [Member]
Troubled Debt Restructuring		391
Commercial and Industrial Portfolio Segment [Member] | Interest Rate Below Market Reduction [Member] | Commercial Real Estate Nonowner Occupied [Member]
Troubled Debt Restructuring	391
Consumer Portfolio Segment [Member] | Interest Rate Below Market Reduction [Member] | Home Equity Loan [Member]
Troubled Debt Restructuring		203
Consumer Portfolio Segment [Member] | Extended Maturity [Member] | Home Equity Loan [Member]
Troubled Debt Restructuring	209	213
Performing Financial Instruments [Member]
Troubled Debt Restructuring	13,513	13,210
Performing Financial Instruments [Member] | Interest Only Payments [Member] | Commercial Real Estate Owner Occupied [Member]
Troubled Debt Restructuring	231
Performing Financial Instruments [Member] | Interest Only Payments [Member] | Commercial Real Estate Nonowner Occupied [Member]
Troubled Debt Restructuring	560
Performing Financial Instruments [Member] | Interest Rate Below Market Reduction [Member] | Commercial Real Estate Nonowner Occupied [Member]
Troubled Debt Restructuring	572
Performing Financial Instruments [Member] | Contractual Interest Rate Reduction [Member] | Commercial Real Estate Nonowner Occupied [Member]
Troubled Debt Restructuring	381
Performing Financial Instruments [Member] | Reduction of Principal and Interest Payments [Member] | Commercial Real Estate Owner Occupied [Member]
Troubled Debt Restructuring	573
Performing Financial Instruments [Member] | Extended Maturity [Member] | Commercial Real Estate Owner Occupied [Member]
Troubled Debt Restructuring	1,560
Performing Financial Instruments [Member] | Residential Portfolio Segment [Member] | Interest Only Payments [Member]
Troubled Debt Restructuring	711	717
Performing Financial Instruments [Member] | Residential Portfolio Segment [Member] | Interest Rate Below Market Reduction [Member]
Troubled Debt Restructuring	204
Performing Financial Instruments [Member] | Commercial Real Estate Portfolio Segment [Member] | Interest Only Payments [Member] | Commercial Real Estate Owner Occupied [Member]
Troubled Debt Restructuring		284
Performing Financial Instruments [Member] | Commercial Real Estate Portfolio Segment [Member] | Interest Only Payments [Member] | Commercial Real Estate Nonowner Occupied [Member]
Troubled Debt Restructuring		600
Performing Financial Instruments [Member] | Commercial Real Estate Portfolio Segment [Member] | Interest Rate Below Market Reduction [Member] | Commercial Real Estate Owner Occupied [Member]
Troubled Debt Restructuring		574
Performing Financial Instruments [Member] | Commercial Real Estate Portfolio Segment [Member] | Contractual Interest Rate Reduction [Member] | Commercial Real Estate Nonowner Occupied [Member]
Troubled Debt Restructuring		384
Performing Financial Instruments [Member] | Commercial Real Estate Portfolio Segment [Member] | Reduction of Principal and Interest Payments [Member] | Commercial Real Estate Owner Occupied [Member]
Troubled Debt Restructuring		579
Performing Financial Instruments [Member] | Commercial Real Estate Portfolio Segment [Member] | Extended Maturity [Member] | Commercial Real Estate Owner Occupied [Member]
Troubled Debt Restructuring		1,582
Performing Financial Instruments [Member] | Commercial and Industrial Portfolio Segment [Member] | Interest Only Payments [Member]
Troubled Debt Restructuring		8,074
Performing Financial Instruments [Member] | Commercial and Industrial Portfolio Segment [Member] | Interest Only Payments [Member] | Commercial Real Estate Nonowner Occupied [Member]
Troubled Debt Restructuring	8,512
Performing Financial Instruments [Member] | Commercial and Industrial Portfolio Segment [Member] | Interest Rate Below Market Reduction [Member]
Troubled Debt Restructuring
Performing Financial Instruments [Member] | Commercial and Industrial Portfolio Segment [Member] | Interest Rate Below Market Reduction [Member] | Commercial Real Estate Nonowner Occupied [Member]
Troubled Debt Restructuring
Performing Financial Instruments [Member] | Consumer Portfolio Segment [Member] | Interest Rate Below Market Reduction [Member] | Home Equity Loan [Member]
Troubled Debt Restructuring		203
Performing Financial Instruments [Member] | Consumer Portfolio Segment [Member] | Extended Maturity [Member] | Home Equity Loan [Member]
Troubled Debt Restructuring	209	213
Nonperforming Financial Instruments [Member]
Troubled Debt Restructuring	2,805	2,833
Nonperforming Financial Instruments [Member] | Interest Only Payments [Member] | Commercial Real Estate Nonowner Occupied [Member]
Troubled Debt Restructuring	2,182
Nonperforming Financial Instruments [Member] | Interest Rate Below Market Reduction [Member] | Commercial Real Estate Nonowner Occupied [Member]
Troubled Debt Restructuring
Nonperforming Financial Instruments [Member] | Contractual Interest Rate Reduction [Member] | Commercial Real Estate Owner Occupied [Member]
Troubled Debt Restructuring	232
Nonperforming Financial Instruments [Member] | Commercial Real Estate Portfolio Segment [Member] | Interest Only Payments [Member] | Commercial Real Estate Nonowner Occupied [Member]
Troubled Debt Restructuring		2,210
Nonperforming Financial Instruments [Member] | Commercial Real Estate Portfolio Segment [Member] | Contractual Interest Rate Reduction [Member] | Commercial Real Estate Owner Occupied [Member]
Troubled Debt Restructuring		232
Nonperforming Financial Instruments [Member] | Commercial and Industrial Portfolio Segment [Member] | Interest Rate Below Market Reduction [Member]
Troubled Debt Restructuring		391
Nonperforming Financial Instruments [Member] | Commercial and Industrial Portfolio Segment [Member] | Interest Rate Below Market Reduction [Member] | Commercial Real Estate Nonowner Occupied [Member]
Troubled Debt Restructuring	$ 391
Nonperforming Financial Instruments [Member] | Consumer Portfolio Segment [Member] | Interest Rate Below Market Reduction [Member] | Home Equity Loan [Member]
Troubled Debt Restructuring