Note 3 - Stock-based Compensation and Shareholders' Equity (Details) - Stock Option Activity (USD $) In Thousands, except Share data, unless otherwise specified	6 Months Ended
	Jun. 30, 2013
Stock Option Activity [Abstract]
Outstanding at December 31, 2012	128,225
Outstanding at December 31, 2012 (in Dollars per share)	$ 22.72
Outstanding at June 30, 2013	116,900
Outstanding at June 30, 2013 (in Dollars per share)	$ 23.45
Outstanding at June 30, 2013	2 years 149 days
Outstanding at June 30, 2013 (in Dollars)	$ 370
Exercisable at June 30, 2013	55,900
Exercisable at June 30, 2013 (in Dollars per share)	$ 25.52
Exercisable at June 30, 2013	1 year 58 days
Exercisable at June 30, 2013 (in Dollars)	$ 190
Granted	20,000
Granted (in Dollars per share)	$ 23.20
Exercised	(28,725)
Exercised (in Dollars per share)	$ 20.35
Forfeited	(2,600)
Forfeited (in Dollars per share)	$ 19.79