Note 1 - Summary of Significant Accounting Policies - Net Income Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net income	$ 2,545	$ 4,324	$ 3,556	$ 6,180	$ 3,584	$ 3,832	$ 3,502	$ 4,074	$ 16,605	$ 14,992	$ 16,459
Less preferred stock dividends and discount accretion							170	225		395	1,927
Net income available to common shareholders, basic and diluted	$ 2,545	$ 4,324	$ 3,556	$ 6,180	$ 3,584	$ 3,832	$ 3,332	$ 3,849	$ 16,605	$ 14,597	$ 14,532
Average common shares outstanding, basic and diluted (in shares)	7,508	7,505	7,502	7,500	7,497	7,495	7,492	7,490	7,504	7,494	7,483
Net income per common share, basic and diluted (in dollars per share)	$ 0.34	$ 0.58	$ 0.47	$ 0.82	$ 0.48	$ 0.51	$ 0.44	$ 0.51	$ 2.21	$ 1.95	$ 1.94