Note 3 - Earnings Per Common Share - Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings per common share - basic
Net income	$ 1,161	$ 1,707	$ 3,935	$ 3,704
Preferred stock dividends
Net income available to common stockholders	$ 1,161	$ 1,707	$ 3,935	$ 3,704
Average common shares outstanding - basic (in shares)	2,271,139	2,204,949	2,271,139	2,174,210
Basic earnings per common share (in dollars per share)	$ 0.51	$ 0.77	$ 1.73	$ 1.70
Earnings per common share - diluted
Net income available to common stockholders	$ 1,161	$ 1,707	$ 3,935	$ 3,704
Average common shares outstanding - basic (in shares)	2,271,139	2,204,949	2,271,139	2,174,210
Add: Dilutive effects of assumed issuance of restricted stock and exercise of stock options (in shares)	20,147	15,471	17,584	16,437
Average shares and dilutive potential common shares (in shares)	2,291,286	2,220,420	2,288,723	2,190,647
Diluted earnings per common share (in dollars per share)	$ 0.51	$ 0.77	$ 1.72	$ 1.69
Stock options not considered in computing earnings per share because they were antidilutive (in shares)