Schedule II (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Provision For Bad Debts [Member]
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at beginning of year	$ 0.3	$ 0.3	$ 0.4
Additions charged to earnings	0.7	0.1
Deductions	(0.3)	(0.1)	(0.1)
Balance at end of year	0.7	0.3	0.3
Provision For Discounts [Member]
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at beginning of year	1.3	1.5	1.3
Additions charged to earnings	21.0	19.2	17.6
Deductions	(20.9)	(19.4)	(17.4)
Balance at end of year	1.4	1.3	1.5
Provision For Warranties [Member]
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at beginning of year	0.4	0.1	0.2
Additions charged to earnings	3.0	4.2	3.2
Deductions	(3.2)	(3.9)	(3.3)
Balance at end of year	0.2	$ 0.4	$ 0.1
Provision For Inventory Obsolescence [Member]
Valuation And Qualifying Accounts Disclosure [Line Items]
Additions charged to earnings	0.6
Deductions	(0.1)
Balance at end of year	$ 0.5