Note 6 - Income Taxes - Reconciliation of Income Taxes Rates (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Statutory rate	21.00%	21.00%
State and local taxes, net of federal benefit	4.70%	3.70%
Equity compensation	0.30%	(5.70%)
Foreign tax credit	(2.70%)
Other	(0.10%)	(0.20%)
Effective rate	23.20%	18.80%