Note 2 - Stock-Based Compensation (Detail) - 2004 Plan Option Plan Status (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2013	Dec. 31, 2012
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 113 days	2 years 204 days
Aggregate Intrinsic Value of Stock Options Outstanding (in Dollars)		$ 25,379,573
Options exercisable at March 31, 2013 and expected to become exercisable	3,006,437
Options exercisable at March 31, 2013 and expected to become exercisable (in Dollars per share)	$ 15.63
Options exercisable at March 31, 2013 and expected to become exercisable (in Dollars)	26,290,048
Options exercisable at March 31, 2013 and expected to become exercisable	2 years 109 days
Options vested and exercisable at March 31, 2013	2,848,738
Options vested and exercisable at March 31, 2013 (in Dollars per share)	$ 15.61
Options vested and exercisable at March 31, 2013 (in Dollars)	24,966,361
Options vested and exercisable at March 31, 2013	2 years 62 days
Options exercised	(626,970)
Options exercised (in Dollars per share)	$ 15.69
Options forfeited and expired	(169,325)
Options forfeited and expired (in Dollars per share)	$ 15.18
Stock Options Outstanding	3,017,066
Weighted Average Exercise Price of Stock Options Outstanding (in Dollars per share)	$ 15.63
Weighted Average Remaining Contractual Term of Stock Options Outstanding	2 years 113 days	2 years 204 days
Aggregate Intrinsic Value of Stock Options Outstanding (in Dollars)	$ 26,390,327