Note 7 - Loans - Average Balance and Interest Income Recognized Related to Impaired Loans (Details) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Average Recorded Investment	$ 118,213	$ 137,405
Interest Income Recognized	1,000	1,207
Commercial Portfolio Segment [Member]
Average Recorded Investment	23,335	12,670
Interest Income Recognized	83,000	120,000
Real Estate Construction Portfolio Segment [Member]
Average Recorded Investment	16,930	20,292
Interest Income Recognized	340,000	65,000
Commercial Real Estate Portfolio Segment [Member]
Average Recorded Investment	61,405,000	87,452,000
Interest Income Recognized	445	890
Residential Mortgage and Equity Lines Portfolio Segment [Member]
Average Recorded Investment	16,543	16,991
Interest Income Recognized	$ 132	$ 132