Note 8 - Business Segments - Reconciling Information Between Reportable Segments and Consolidated Totals (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Revenue	$ 192,113	$ 199,038
Operating income (loss)	61,057	53,725
Interest income	402	293
Interest expense, net	(17,273)	(21,223)
Derivatives and foreign currency transaction gains (losses)	393	472
Income attributable to sale of tax benefits	4,132	7,764
Other non-operating income (expense), net	78	91
Total consolidated income before income taxes and equity in income of investees	48,789	41,122
Intersegment Eliminations [Member]
Revenue	8,656	18,261
Consolidation, Eliminations [Member]
Revenue	$ (8,656)	$ (18,261)