Note 5 - Net Income Per Common Share - Net Income Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Net income, basic and diluted	$ 3,556,000	$ 3,502,000	$ 9,736,000	$ 7,576,000
Less preferred stock dividends	0	170,000	0	395,000
Net income available to common shareholders, basic and diluted	$ 3,556,000	$ 3,332,000	$ 9,736,000	$ 7,181,000
Average common shares issued and outstanding, basic and diluted (in shares)	7,502	7,492	7,501	7,491
Net income per common share, basic and diluted (in dollars per share)	$ 0.47	$ 0.44	$ 1.30	$ 0.96