Note 23 - 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								12 Months Ended
		Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Net income available to the Company's common shareholders										$ 439,604	$ 372,461	$ 332,630
Change in estimated redemption value of redeemable noncontrolling interests										(7,521)
Earnings attributable to participating securities										(2,375)	(2,132)	(2,018)
Net income available to the Company’s common shareholders for basic earnings per share										429,708	370,329	330,612
Distributions on convertible units										99
Net income available to the Company’s common shareholders for diluted earnings per share										$ 429,807	$ 370,329	$ 330,612
Weighted average common shares outstanding – basic (in shares)										420,641	423,614	418,402
Effect of dilutive securities (1):
Equity awards (in shares)	[1]									628	405	1,307
Assumed conversion of convertible units (in shares)	[1]									110
Weighted average common shares outstanding – diluted (in shares)	[1]									421,379	424,019	419,709
Basic earnings per share (in dollars per share)		$ 0.17	$ 0.19	$ 0.36	$ 0.30	$ 0.17	$ 0.24	$ 0.31	$ 0.15	$ 1.02	$ 0.87	$ 0.79
Diluted earnings per share (in dollars per share)		$ 0.17	$ 0.19	$ 0.36	$ 0.30	$ 0.17	$ 0.24	$ 0.31	$ 0.15	$ 1.02	$ 0.87	$ 0.79

[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 1.3 million, 3.1 million and 3.5 million stock options that were not dilutive as of December 31, 2018, 2017 and 2016, respectively.