Schedule II- Valuation and Qualifying Account (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2018	Dec. 31, 2017
Allowance for Doubtful Accounts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	$ 4.9	$ 5.7	$ 7.6
Charged to (Reversed from) Costs and Expenses	1.7	(0.8)	(2.0)
Write-offs, Net of Recoveries	(1.1)	0.0	0.1
Balance at End of Year	5.5	4.9	5.7
Sales return reserve	5.5	5.7	7.6		$ 5.7
Sales Return Reserve
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	32.7	55.2	71.4
Balance at beginning of year, excluding reduction of cumulative effect adjustment, topic 606					44.5
Charged as a Reduction in Revenues	59.5	70.7	25.0
Charged to Other Accounts	0.0	0.0	65.9
Used	(67.4)	(82.5)	(107.1)
Balance at End of Year	24.8	32.7	55.2
Sales return reserve	$ 32.7	$ 55.2	$ 55.2		$ 55.2
Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09 | Sales Return Reserve
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Sales return reserve				$ (10.7)