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		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Net income	$ 1,103,000	$ 1,019,000	$ 2,457,000	$ 2,323,000
Shares (denominator):
Basic weighted average common shares outstanding (in shares)	14,732,173	16,695,059	14,962,606	17,190,073
Add: dilutive effect of common stock options (in shares)	201,253	11,473	113,334
Diluted weighted average common shares outstanding (in shares)	14,933,426	16,706,532	15,075,940	17,190,073
Earnings per common share:
Basic (in dollars per share)	$ 0.07	$ 0.06	$ 0.16	$ 0.14
Diluted (in dollars per share)	$ 0.07	$ 0.06	$ 0.16	$ 0.14