Note 4 - Earnings Per Share (Details) - Earnings Per Share - Basic and Diluted Loss Per Share (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Numerator
Net income	$ 21,542	$ 224,909	$ 33,046	$ 247,425
Less: distributed earnings allocated to participating securities	(49)		(101)
Less: undistributed earnings allocated to participating securities	(37)	(2,069)	(39)	(2,310)
Net income attributable to common stockholders (numerator for basic earnings per share)	21,456	222,840	32,906	245,115
Add back: undistributed earnings allocated to participating securities	37	2,069	39	2,310
Less: undistributed earnings reallocated to participating securities	(37)	(2,049)	(38)	(2,286)
Numerator for diluted earnings per share under two class method	$ 21,456	$ 222,860	$ 32,907	$ 245,139
Denominator
Weighted-average common shares outstanding (in Shares)	48,640,979	48,478,076	48,613,521	48,410,486
Denominator for diluted earnings per share under two class method (in Shares)	48,852,696	48,946,055	48,842,527	48,916,988
Basic Earnings Per Common Share (in Dollars per share)	$ 0.44	$ 4.60	$ 0.68	$ 5.06
Diluted Earnings Per Common Share (in Dollars per share)	$ 0.44	$ 4.55	$ 0.67	$ 5.01
Employee Stock Option [Member]
Denominator
Add: dilutive effect of stock options (in Shares)	211,717	467,979	229,006	506,502