Note 3 - Revenue - Contract Liabilities (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Sales Incentives [Member]
Beginning balance	$ 12.1	$ 13.7
Additions to sales incentive accrual	5.2	5.4
Contract payments	(5.7)	(8.2)
Foreign currency fluctuations	(0.2)	(0.2)
Divestiture of business	(0.1)	0.0
Ending balance	11.3	10.7
Maintenance [Member]
Foreign currency fluctuations	0.0	(0.1)
Beginning balance	9.3	10.7
Increase in deferred revenue representing our obligation to satisfy future performance obligations	4.1	2.7
Decrease in deferred revenue for amounts recognized in Net Sales for satisfied performance obligations	(3.4)	(2.5)
Ending balance	$ 10.0	$ 10.8