Note 4 - Earnings Per Share (Details) - Earnings Per Share Calculation (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Numerator for basic and diluted earnings per share –
Net income available to common shareholders (in Dollars)	$ 16,781	$ 12,014
Denominator–
Denominator for basic earnings per share – weighted average shares outstanding	40,066	39,332
Effect of dilutive securities–
Employee and director stock options and restricted share awards	919	1,179
Denominator for diluted earnings per share – adjusted weighted average shares outstanding and assumed conversions	40,985	40,511
Basic earnings per common share (in Dollars per share)	$ 0.42	$ 0.31
Diluted earnings per common share and common share equivalents (in Dollars per share)	$ 0.41	$ 0.30