Note 9 - Business Segments - Reconciling Information Between Reportable Segments and Consolidated Totals (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Revenues	$ 189,898	$ 151,594
Operating income	59,496	50,543
Interest income	244	320
Interest expense, net	(14,923)	(16,023)
Derivatives and foreign currency transaction gains (losses)	1,338	1,962
Income attributable to sale of tax benefits	6,157	4,398
Other non-operating income (expense), net	(92)	191
Total consolidated income before income taxes and equity in income of investees	52,220	41,391
Intersegment Eliminations [Member]
Revenues	16,213	1,941
Consolidation, Eliminations [Member]
Revenues	$ (16,213)	$ (1,941)