Note 6 - Earnings Per Share - Calculation of Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Net income	$ 2,064	$ 1,573
Basic earnings per common share (in dollars per share)	$ 0.42	$ 0.32
Diluted earnings per common share (in dollars per share)	$ 0.40	$ 0.31
Basic shares (in shares)	4,911	4,842
Diluted shares (in shares)	5,164	5,058