Note 9 - Business Segments (Details) - Reconciling Information Between Reportable Segments and Consolidated Totals - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Revenue:
Revenue	$ 162,852	$ 140,242	$ 423,570	$ 410,281
Operating income:
Operating income	46,479	43,788	114,973	108,689
Interest income	53	35	106	236
Interest expense, net	(17,748)	(22,494)	(54,435)	(65,084)
Foreign currency translation and transaction gains (losses)	1,296	(2,946)	(641)	(3,639)
Income attributable to sale of equity interest	8,634	5,487	18,917	18,334
Gain from sale of property, plant and equipment			(531)	7,628
Other non-operating income (expense), net	(131)	243	(1,523)	649
Total consolidated income before income taxes and equity in income of investees	38,583	24,113	77,397	66,813
Total Segment Revenues [Member]
Revenue:
Revenue	162,852	140,242	423,570	410,281
Intersegment Eliminations [Member]
Revenue:
Revenue	10,657	7,244	41,314	43,580
Consolidation, Eliminations [Member]
Revenue:
Revenue	$ (10,658)	$ (7,244)	$ (41,314)	$ (43,580)