Note 2 - Net Income per Common Share (Details) - Computation of Basic and Diluted Net Income per Share (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Computation of Basic and Diluted Net Income per Share [Abstract]
Net income (in Dollars)	$ 10,102	$ 8,287
Basic - weighted-average shares outstanding:	25,573,851	25,014,907
Effect of dilutive securities:
Employee stock options and other	517,218	630,837
Diluted - weighted-average shares outstanding:	26,091,069	25,645,744
Net income per share:
Basic (in Dollars per share)	$ 0.40	$ 0.33
Diluted (in Dollars per share)	$ 0.39	$ 0.32