Note 4 - Income Taxes (Details Textual) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Effective Income Tax Rate Reconciliation, Percent, Total	24.80%	9.80%	22.70%	2.30%
Effective Income Tax Rate Change, Share-based Compensation	$ 1,300,000		$ 4,100,000
Change in Tax Law, Deferral of Social Security Tax Payments					$ 1,313,000
Social Security Tax Payable, Current	$ 656,000		$ 656,000