Note 4 - Earnings Per Share - Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Warrant [Member]
Dilutive effect of weighted-average outstanding common share equivalents
Warrants (in shares)	569,949	606,803	520,686	507,002
Employee Stock Option [Member]
Dilutive effect of weighted-average outstanding common share equivalents
Warrants (in shares)	95,850	123,910	90,461	124,135
Restricted Stock Units (RSUs) [Member]
Dilutive effect of weighted-average outstanding common share equivalents
Warrants (in shares)	165,410	79,477	143,860	51,343
Net Income (Loss) Attributable to Parent	$ 46,090	$ 38,483	$ 127,084	$ 119,663
Basic weighted-average number of common shares outstanding (in shares)	78,865,860	81,475,288	79,147,839	80,422,711
Diluted weighted-average number of common shares outstanding (in shares)	79,697,069	82,285,478	79,902,846	81,105,191
Average stock options and warrants with anti-dilutive effect (in shares)	207,183	760,291	247,974	1,082,400
Basic (in dollars per share)	$ 0.58	$ 0.47	$ 1.61	$ 1.49
Diluted (in dollars per share)	$ 0.58	$ 0.47	$ 1.59	$ 1.48