Note 2 - Per Share Data (Details) - Net Income Per Share - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Net Income Per Share [Abstract]
Net income (in Dollars)	$ 4,357,000	$ 4,163,000	$ 8,172,000	$ 8,451,000
Weighted average common shares - basic	12,199,996	12,441,679	12,233,964	12,429,717
Earnings per share – basic (in Dollars per share)	$ 0.36	$ 0.33	$ 0.67	$ 0.68
Dilutive effect of potential common stock arising from stock options:
Exercise of outstanding stock options	205,024	174,840	218,115	239,291
Hypothetical share repurchase	(182,494)	(157,135)	(196,407)	(217,549)
Weighted average common shares - diluted	12,222,526	12,459,384	12,255,672	12,451,459
Earnings per share – diluted (in Dollars per share)	$ 0.36	$ 0.33	$ 0.67	$ 0.68