Note 2 - Per Share Data (Details) - Net Income Per Share (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Net Income Per Share [Abstract]
Net Income (in Dollars)	$ 4,974,000	$ 5,685,000	$ 9,680,000	$ 11,272,000
Weighted Average Number of Shares Outstanding, Basic	12,342,755	12,225,808	12,331,943	12,216,339
Earnings per share – basic (in Dollars per share)	$ 0.40	$ 0.46	$ 0.78	$ 0.92
Dilutive effect of potential common stock arising from stock options:
Weighted Average Number of Shares Outstanding	252,380	137,591	254,900	204,836
Weighted Average Number of Shares Outstanding	(225,824)	(120,566)	(227,559)	(177,872)
Weighted Average Number of Shares Outstanding, Diluted	12,369,311	12,242,833	12,359,284	12,243,303
Earnings per share – diluted (in Dollars per share)	$ 0.40	$ 0.46	$ 0.78	$ 0.92