Note 24 - Supplemental Financial Information (Unaudited) - Quarterly Results of Operations (Details) - USD ($) $ / shares in Units, $ 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
Revenues	$ 284,201	$ 283,080	$ 293,403	$ 304,078	$ 315,225	$ 294,845	$ 297,176	$ 293,588	$ 1,164,762	$ 1,200,834	$ 1,170,792
Net income attributable to the Company	$ 88,161	$ 100,158	$ 165,386	$ 144,090	$ 84,896	$ 121,030	$ 143,416	$ 76,733	$ 497,795	$ 426,075	$ 378,850
Basic (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 (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