Note 9 - Business Segments - Reconciling Information Between Reportable Segments and Consolidated Totals (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenues	$ 199,038	$ 184,023
Operating income (loss)	53,725	54,593
Interest income	293	113
Interest expense, net	(21,223)	(14,344)
Derivatives and foreign currency transaction gains (losses)	472	(1,599)
Income attributable to sale of tax benefits	7,764	7,361
Other non-operating income (expense), net	91	(20)
Total consolidated income from operations before income taxes and equity in earnings of investees	41,122	46,104
Intersegment Eliminations [Member]
Revenues	18,261	24,827
Consolidation, Eliminations [Member]
Revenues	$ (18,261)	$ (24,827)