Note 17 - 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, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Net income available to the Company's common shareholders		$ 150,852	$ 131,861	$ 280,353	$ 197,039
Earnings attributable to participating securities		(863)	(647)	(1,472)	(1,070)
Net income available to the Company’s common shareholders for basic earnings per share		149,989	131,214	278,881	195,969
Distributions on convertible units		282	259	521	29
Net income available to the Company’s common shareholders for diluted earnings per share		$ 150,271	$ 131,473	$ 279,402	$ 195,998
-Basic (in shares)		420,731	423,650	422,060	423,516
Effect of dilutive securities (1):
Equity awards (in shares)	[1]	350	432	352	505
Assumed conversion of convertible units (in shares)	[1]	847	862	824	63
Weighted average common shares outstanding – diluted (in shares)	[1]	421,928	424,944	423,236	424,084
Basic earnings per share (in dollars per share)		$ 0.36	$ 0.31	$ 0.66	$ 0.46
Diluted earnings per share (in dollars per share)		$ 0.36	$ 0.31	$ 0.66	$ 0.46

[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 3.2 million and 4.0 million stock options that were not dilutive as of June 30, 2018 and 2017, respectively, and 2.3 million shares of restricted stock that were not dilutive for the three months ended June 30, 2018.