Note 9 - Basic and Diluted Earnings Per Common Share - Reconciliation of Net Income and Number of Shares Used in Computations of Basic and Diluted EPS (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Net income	$ 804,000	$ 797,000	$ 1,354,000	$ 1,304,000
Shares (denominator):
Basic weighted average common shares outstanding (in shares)	14,953,217	17,211,268	15,079,733	17,440,299
Add: dilutive effect of common stock options (in shares)	52,872		71,299
Diluted weighted average common shares outstanding (in shares)	15,006,089	17,211,268	15,151,032	17,440,299
Earnings per common share:
Basic (in dollars per share)	$ 0.05	$ 0.05	$ 0.09	$ 0.07
Diluted (in dollars per share)	$ 0.05	$ 0.05	$ 0.09	$ 0.07