Note 8 - Net Income Per Common Share (Details) - Net Income Per Common Share Calculation - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Basic:
Net income available to common shareholders (in Dollars)	$ 21,283	$ 13,937	$ 61,280	$ 39,097
Average common shares outstanding	33,401	26,024	32,625	25,978
Basic net income per common share (in Dollars per share)	$ 0.64	$ 0.54	$ 1.88	$ 1.50
Diluted:
Adjustment for common share equivalents	625	630	653	640
Average common shares outstanding-diluted	34,026	26,654	33,278	26,618
Diluted net income per common share (in Dollars per share)	$ 0.63	$ 0.52	$ 1.84	$ 1.47
Anti-dilutive shares		21	11	21