Note 18 - Income Taxes - Difference Between US Federal Statutory Tax Rate and Company's Effective Tax Rate (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
U.S. federal statutory tax rate	21.00%	35.00%	35.00%
Impact of federal tax reform	2.60%	(12.40%)
Transition tax inclusion	(5.70%)	42.10%
Foreign tax credits	(4.20%)	(50.50%)
Tax basis adjustment			(4.90%)
Withholding tax	5.90%	34.10%
State income tax, net of federal benefit	1.00%	1.10%	(0.60%)
Uncertain Tax Positions	2.10%
Effect of foreign income tax, net	5.60%	(10.70%)	(10.30%)
Production tax credits	(3.10%)	(1.20%)	(8.30%)
Subpart F income	0.50%	1.70%	0.30%
Tax on global intangible low-tax income	18.60%
Intra-entity transfers of assets other than inventory	(2.10%)
Other, net	0.30%	(3.90%)	(1.40%)
Effective tax rate	25.30%	12.70%	26.30%
Domestic Tax Authority [Member]
Valuation allowance	(17.20%)	(22.60%)	16.50%