Note 3 - Revenue - Contract Liabilities (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Sales Incentives [Member]
Beginning balance	$ 12.1	$ 13.7
Additions to sales incentive accrual	29.9	15.0
Contract payments	(26.1)	(15.6)
Foreign currency fluctuations	0.2	(0.1)
Divestiture of business	(0.1)	0.0
Ending balance	16.0	13.0
Maintenance [Member]
Foreign currency fluctuations	0.0	(0.8)
Beginning balance	9.3	10.7
Increase in deferred revenue representing our obligation to satisfy future performance obligations	25.9	15.3
Decrease in deferred revenue for amounts recognized in net sales for satisfied performance obligations	(25.2)	(15.0)
Ending balance	$ 10.0	$ 10.2