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		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Net income available to the Company's common shareholders		$ 59,048	$ 85,624	$ 247,176	$ 365,977
Change in estimated redemption value of redeemable noncontrolling interests		0	(3,918)	0	(3,918)
Earnings attributable to participating securities		(654)	(604)	(1,939)	(1,818)
Net income available to the Company’s common shareholders for basic earnings per share		58,394	81,102	245,237	360,241
Distributions on convertible units		0	0	20	683
Net income available to the Company’s common shareholders for diluted earnings per share		$ 58,394	$ 81,102	$ 245,257	$ 360,924
Weighted average common shares outstanding – basic (in shares)		419,823	419,230	419,663	421,106
Equity awards (in shares)	[1]	1,120	534	1,273	515
Assumed conversion of convertible units (in shares)	[1]	59	0	50	822
Weighted average common shares outstanding – diluted (in shares)	[1]	421,002	419,764	420,986	422,443
Basic earnings per share (in dollars per share)		$ 0.14	$ 0.19	$ 0.58	$ 0.86
Diluted earnings per share (in dollars per share)		$ 0.14	$ 0.19	$ 0.58	$ 0.85

[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 0.5 million and 2.3 million stock options that were not dilutive as of September 30, 2019 and 2018, respectively.