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
	Mar. 31, 2017	Mar. 31, 2016
Net income	$ 550,000	$ 507,000
Shares (denominator):
Basic weighted average common shares outstanding (in shares)	15,207,659	17,669,331
Add: dilutive effect of common stock options (in shares)	94,142
Diluted weighted average common shares outstanding (in shares)	15,301,801	17,669,331
Earnings per common share:
Basic (in dollars per share)	$ 0.04	$ 0.03
Diluted (in dollars per share)	$ 0.04	$ 0.03