Note 18 - Income Taxes - Difference Between US Federal Statutory Tax Rate and Company's Effective Tax Rate (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
U.S. federal statutory tax rate	21.00%	21.00%	35.00%
Impact of federal tax reform	0.00%	2.60%	(12.40%)
Transition tax inclusion		(5.70%)	42.10%
Foreign tax credits	(22.80%)	(4.20%)	(50.50%)
Withholding tax	10.40%	5.90%	34.10%
State income tax, net of federal benefit	3.70%	1.00%	1.10%
Uncertain tax positions	2.10%	2.10%
Effect of foreign income tax, net	9.70%	5.60%	(10.70%)
Production tax credits	(5.00%)	(3.10%)	(1.20%)
Subpart F income	0.50%	0.50%	1.70%
Tax on global intangible low-tax income	16.90%	18.60%
Intra-entity transfers of assets other than inventory	0.30%	(2.10%)
Other, net	0.10%	0.30%	(3.90%)
Effective tax rate	33.20%	25.30%	12.70%
Domestic Tax Authority [Member]
Valuation allowance	(3.70%)	(17.20%)	(22.60%)