Note 2 - Stock-Based Compensation (Details) - Plan Option Plan Status (USD $)	9 Months Ended	12 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Plan Option Plan Status [Abstract]
Stock Options Outstanding		3,813,361
Weighted Average Exercise Price of Stock Options Outstanding (in Dollars per share)		$ 15.62
Weighted Average Remaining Contractual Term of Stock Options Outstanding	2 years 3 days	2 years 204 days
Aggregate Intrinsic Value of Stock Options Outstanding (in Dollars)		$ 25,379,573
Options exercisable at September 30, 2013 and expected to become exercisable	1,693,071
Options exercisable at September 30, 2013 and expected to become exercisable (in Dollars per share)	$ 15.77
Options exercisable at September 30, 2013 and expected to become exercisable (in Dollars)	24,594,612
Options exercisable at September 30, 2013 and expected to become exercisable	2 years
Options vested and exercisable at September 30, 2013	1,592,588
Options vested and exercisable at September 30, 2013 (in Dollars per share)	$ 15.82
Options vested and exercisable at September 30, 2013 (in Dollars)	23,044,939
Options vested and exercisable at September 30, 2013	1 year 310 days
Options exercised	(2,106,632)
Options exercised (in Dollars per share)	$ 15.50
Options forfeited and expired	(9,168)
Options forfeited and expired (in Dollars per share)	$ 16.87
Stock Options Outstanding	1,697,561
Weighted Average Exercise Price of Stock Options Outstanding (in Dollars per share)	$ 15.76
Weighted Average Remaining Contractual Term of Stock Options Outstanding	2 years 3 days	2 years 204 days
Aggregate Intrinsic Value of Stock Options Outstanding (in Dollars)	$ 24,670,713