Note 5 - Loans - Average Recorded Investment and Interest Income Recognized on Impaired Loans by Loan Class (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Average recorded investment	$ 18,323	$ 25,299	$ 36,119
Interest income recognized	286	298	423
Commercial Portfolio Segment [Member]
Average recorded investment	2,605	3,533	6,222
Interest income recognized	23	22	33
Commercial Portfolio Segment [Member] | Commercial Owner Occupied Loan [Member]
Interest income recognized	25
Commercial Real Estate Portfolio Segment [Member] | Commercial Non-owner Occupied [Member]
Average recorded investment	2,013	7,306	11,277
Interest income recognized	47	49	165
Commercial Real Estate Portfolio Segment [Member] | Commercial Owner Occupied Loan [Member]
Average recorded investment	1,281	2,212	5,233
Interest income recognized		59	78
Residential Portfolio Segment [Member] | Individual Tax Identification Number Loan [Member]
Average recorded investment	8,939	9,679	10,668
Interest income recognized	165	141	114
Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Mortgage Receivable [Member]
Average recorded investment	1,788	1,786	1,561
Interest income recognized
Residential Portfolio Segment [Member] | Home Equity Loan [Member]
Average recorded investment	1,535	750	1,141
Interest income recognized	26	27	33
Consumer Portfolio Segment [Member]
Average recorded investment	162	33	17
Interest income recognized