Note 5 - Loans - Average Recorded Investment and Interest Income Recognized on Impaired Loans by Loan Class (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Average recorded investment	$ 17,745	$ 17,747
Interest income recognized	68	65
Commercial Portfolio Segment [Member]
Average recorded investment	3,396	2,215
Interest income recognized	10	1
Commercial Portfolio Segment [Member] | Commercial Owner Occupied Loan [Member]
Interest income recognized	2
Commercial Real Estate Portfolio Segment [Member] | Commercial Non-owner Occupied [Member]
Average recorded investment	2,004	2,020
Interest income recognized	11	12
Commercial Real Estate Portfolio Segment [Member] | Commercial Owner Occupied Loan [Member]
Average recorded investment	809	1,449
Interest income recognized		6
Residential Portfolio Segment [Member] | Individual Tax Identification Number Loan [Member]
Average recorded investment	8,272	9,158
Interest income recognized	40	40
Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Mortgage Receivable [Member]
Average recorded investment	1,728	1,753
Interest income recognized
Residential Portfolio Segment [Member] | Home Equity Loan [Member]
Average recorded investment	1,361	1,120
Interest income recognized	5	6
Consumer Portfolio Segment [Member]
Average recorded investment	175	32
Interest income recognized