Note 11 - Summary of Basic and Diluted Earnings Per Share (Details) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Net income	$ 24,527	$ 13,947	$ 39,997
Weighted average common shares outstanding-basic (in shares)	87,881	87,673	87,598
Plus: net effect of dilutive stock options and restricted common shares (in shares)	480	491	746
Weighted average common shares outstanding-diluted (in shares)	88,361	88,164	88,344
Net income per common share - basic (in dollars per share)	$ 0.28	$ 0.16	$ 0.46
Net income per common share - diluted (in dollars per share)	$ 0.28	$ 0.16	$ 0.45