Note 4 - Earnings Per Common Share (Details) - Components Used in Computation of Basic and Diluted Earnings Per Common 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	$ 57,198	$ 56,463	$ 88,803	$ 94,622
Less: Net income allocated to preferred shareholder	(13,798)	(13,496)	(21,475)	(22,650)
Less: Net income allocated to unvested restricted stock	(112)	(77)	(181)	(134)
Net income available to common stockholders for basic earnings per common share	43,288	42,890	67,147	71,838
Effect of dilutive securities:
Net income allocated to preferred shareholder	13,798	13,496	21,475	22,650
Net income available to common and preferred stock for diluted earnings per share	$ 57,127	$ 56,427	$ 88,826	$ 94,692
Denominator:
Weighted average basic common shares outstanding (in Shares)	275,498,449	279,075,416	274,572,173	278,514,992
Weighted average additional common shares outstanding if preferred shares converted to common shares (if dilutive (in Shares)	87,812,786	87,812,786	87,812,786	87,812,786
Total weighted average common shares outstanding if preferred shares converted to common shares (in Shares)	363,311,235	366,888,202	362,384,959	366,327,778
Effect of dilutive securities:
Share-based awards (in Shares)	3,742,596	6,339,326	4,522,634	6,624,087
Weighted average diluted shares outstanding (in Shares)	398,366,681	404,540,378	398,220,443	404,264,715
Income per common share:
Basic (in Dollars per share)	$ 0.16	$ 0.15	$ 0.24	$ 0.26
Diluted (in Dollars per share)	$ 0.14	$ 0.14	$ 0.22	$ 0.23
1¼% Convertible Senior Notes Due August 2032 [Member]
Effect of dilutive securities:
Interest on 1¼% convertible senior notes due 2032, capitalized and amortized in cost of sales	$ 41	$ 41	$ 204	$ 204
Effect of dilutive securities:
1¼% convertible senior notes due 2032 (in Shares)	31,312,850	31,312,850	31,312,850	31,312,850