Note 7 - Income Taxes - Income Tax Rate Reconciliation (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statutory Federal income tax rate	21.00%	21.00%	21.00%	21.00%
State and local income taxes, net of Federal income tax benefit	4.30%	4.90%	3.70%	4.40%
Current year untaxed foreign income	(6.90%)	(9.10%)	(7.20%)	(8.10%)
Foreign taxes	3.80%	1.90%	3.20%	3.00%
GILTI tax	1.60%	4.20%	1.70%	3.70%
Compensation related		1.60%	0.10%	1.30%
Non-deductible acquisition expense		2.80%		1.70%
Federal tax credits			(0.50%)	(0.60%)
Other		(2.20%)	0.20%	(0.90%)
Effective income tax rate	23.80%	25.10%	22.20%	25.50%