Note 1 - Summary of Significant Interim Accounting Policies - Reconciliation of Basic and Diluted Earnings Per Share (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Net earnings used in the computation of basic and diluted earnings per share	$ 4,386,000	$ 4,031,000	$ 9,721,000	$ 9,698,000
Weighted average shares outstanding - basic (in shares)	14,118,354	13,833,561	14,055,345	13,716,376
Common stock equivalents (in shares)	865,730	752,127	814,726	853,995
Weighted average shares outstanding - diluted (in shares)	14,984,084	14,585,688	14,870,071	14,570,371
Net earnings, basic (in dollars per share)	$ 0.31	$ 0.29	$ 0.69	$ 0.71
Net earnings, diluted (in dollars per share)	$ 0.29	$ 0.28	$ 0.65	$ 0.67