Note 10 - Income Taxes (Details Textual) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Unrecognized Tax Benefits, Ending Balance	$ 27.7		$ 29.1
Liability for Uncertainty in Income Taxes, Current	2.4		2.2
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense, Total	0.6	$ 0.5
Income Tax Expense (Benefit) on Reversal of Interest and Penalties	0.5
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued, Total	$ 5.0		$ 4.9