Note 4 - Share-Based Compensation (Detail) - Stock option activity (USD $) In Thousands, except Share data, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Outstanding at December 31, 2011	769,401
Outstanding at December 31, 2011 (in Dollars per share)	$ 25.73
Granted	79,630	116,008
Granted (in Dollars per share)	$ 45.28
Exercised	(116,358)
Exercised (in Dollars per share)	$ 19.07
Cancelled	(107,505)
Cancelled (in Dollars per share)	$ 26.65
Outstanding at June 30, 2012	625,168
Outstanding at June 30, 2012 (in Dollars per share)	$ 29.30
Outstanding at June 30, 2012	6 years 226 days
Outstanding at June 30, 2012 (in Dollars)	$ 14,411
Exercisable at June 30, 2012	354,166
Exercisable at June 30, 2012 (in Dollars per share)	$ 24.82
Exercisable at June 30, 2012	5 years 153 days
Exercisable at June 30, 2012 (in Dollars)	$ 9,749