Note 14 - Earnings Per Share - Reconciliation of Earnings (Loss) and the Weighted Average Number of Shares (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Net income available to the Company's common shareholders		$ 86,493	$ 150,852	$ 188,128	$ 280,353
Earnings attributable to participating securities		(660)	(863)	(1,285)	(1,472)
Net income available to the Company’s common shareholders for basic earnings per share		85,833	149,989	186,843	278,881
Distributions on convertible units		0	282	20	521
Net income available to the Company’s common shareholders for diluted earnings per share		$ 85,833	$ 150,271	$ 186,863	$ 279,402
Weighted average common shares outstanding – basic (in shares)		419,697	420,731	419,581	422,060
Effect of dilutive securities (1):
Equity awards (in shares)	[1]	949	350	1,166	352
Assumed conversion of convertible units (in shares)	[1]	0	847	51	824
Weighted average common shares outstanding – diluted (in shares)		420,646	421,928	420,798	423,236
Basic earnings per share (in dollars per share)		$ 0.20	$ 0.36	$ 0.45	$ 0.66
Diluted earnings per share (in dollars per share)		$ 0.20	$ 0.36	$ 0.44	$ 0.66

[1] The effect of the assumed conversion of certain convertible units had an anti-dilutive effect upon the calculation of Net income available to the Company’s common shareholders per share. Accordingly, the impact of such conversions has not been included in the determination of diluted earnings per share calculations. Additionally, there were 1.3 million and 3.2 million stock options that were not dilutive as of June 30, 2019 and 2018, respectively, and 2.3 million of restricted stock that were not dilutive for the three months ended  June 30, 2018.