Note 11 - Income Taxes (Details Textual) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Unrecognized Tax Benefits, Ending Balance	$ 28.7		$ 28.4
Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations	4.1
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense, Total	0.2	$ 0.2
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued, Total	$ 5.2		$ 5.0