Note 2 - Per Share Data (Tables)

6 Months Ended

Jun. 30, 2015

Earnings Per Share [Abstract]

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

		Weighted-
		Average		Earnings
	Net	Common		Per
	Income	Shares		Share
Six Months Ended June 30, 2015
Earnings per share – basic	$8,172,000	12,233,964		$0.67
Dilutive effect of potential common stock arising from stock options:
Exercise of outstanding stock options		218,115
Hypothetical share repurchase at $19.97		(196,407	)
Earnings per share – diluted	$8,172,000	12,255,672		$0.67
Six Months Ended June 30, 2014
Earnings per share – basic	$8,451,000	12,429,717		$0.68
Dilutive effect of potential common stock arising from stock options:
Exercise of outstanding stock options		239,291
Hypothetical share repurchase at $19.25		(217,549	)
Earnings per share – diluted	$8,451,000	12,451,459		$0.68

		Weighted-
		Average		Earnings
	Net	Common		Per
	Income	Shares		Share
Three Months Ended June 30, 2015
Earnings per share – basic	$4,357,000	12,199,996		$0.36
Dilutive effect of potential common stock arising from stock options:
Exercise of outstanding stock options		205,024
Hypothetical share repurchase at $20.15		(182,494	)
Earnings per share – diluted	$4,357,000	12,222,526		$0.36
Three Months Ended June 30, 2014
Earnings per share – basic	$4,163,000	12,441,679		$0.33
Dilutive effect of potential common stock arising from stock options:
Exercise of outstanding stock options		174,840
Hypothetical share repurchase at $18.81		(157,135	)
Earnings per share – diluted	$4,163,000	12,459,384		$0.33