Note 9 - Earnings Per Share (Details) - Basic and Diluted Earnings Per Share - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Numerator:
Net income	$ 6,634	$ 6,672	$ 12,871	$ 12,959
Less dividends on convertible preferred stock	(1,104)		(1,698)
Less amortization of convertible preferred stock discount	(825)		(1,071)
Less income allocated to participating securities	(524)		(859)
Net income available to common stockholders	$ 4,181	$ 6,672	$ 9,243	$ 12,959
Denominator:
Denominator for basic earnings per share -- weighted-average shares	16,097,198	14,171,013	16,036,959	14,006,944
Effect of dilutive securities:
Denominator for diluted earnings per share -- adjusted weighted-average shares assumed conversion	16,240,898	14,453,964	16,193,372	14,306,898
Basic earnings per share	$ 0.26	$ 0.47	$ 0.58	$ 0.93
Diluted earnings per share	$ 0.26	$ 0.46	$ 0.57	$ 0.91
Stock Options and RSAs [Member]
Effect of dilutive securities:
Common stock options and restricted stock awards	143,700	265,779	156,413	282,782
Restricted Stock Units (RSUs) [Member]
Effect of dilutive securities:
Performance-based restricted stock units		17,172		17,172