Note 1 - Interim Financial Statements - Reconciliation of Earnings (Loss) and the Weighted Average Number of Shares (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
Net income available to the Company's common shareholders		$ 65,178	$ 129,158
Earnings attributable to participating securities		(531)	(629)
Net income available to the Company’s common shareholders for basic earnings per share		64,647	128,529
Distributions on convertible units			13
Net income available to the Company’s common shareholders for diluted earnings per share		$ 64,647	$ 128,542
Weighted average common shares outstanding – basic (in shares)		423,381	412,630
Effect of dilutive securities (a):
Equity awards (in shares)	[1]	765	1,453
Assumed conversion of convertible units (in shares)	[1]		62
Weighted average common shares outstanding – diluted (in shares)		424,146	414,145
-Basic (in dollars per share)		$ 0.15	$ 0.31
-Diluted (in dollars per share)		$ 0.15	$ 0.31

[1] The effect of the assumed conversion of certain convertible units had an anti-dilutive effect upon the calculation of Income from continuing operations per share. Accordingly, the impact of such conversions has not been included in the determination of diluted earnings per share calculations. Additionally, there were 3,445,600 and 5,235,280 stock options that were not dilutive as of March 31, 2017 and 2016, respectively.