Note 3 - Revenue - Contract Liabilities (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Sales Incentives [Member]
Beginning balance	$ 19.9	$ 12.1
Additions to sales incentive accrual	4.4	5.2
Contract payments	(12.8)	(5.7)
Foreign currency fluctuations	(0.2)	(0.3)
Ending balance	11.3	11.3
Maintenance [Member]
Foreign currency fluctuations	0.1	0.0
Beginning balance	11.2	9.3
Increase in deferred revenue representing our obligation to satisfy future performance obligations	7.4	4.1
Decrease in deferred revenue for amounts recognized in net sales for satisfied performance obligations	(6.5)	(3.4)
Ending balance	$ 12.2	$ 10.0