Schedule II - Valuation and Qualifying Account - Sales Return Reserve (Details) - Sales Return Reserve - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2018
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	$ 24.8	$ 32.7	$ 44.5
Charged as a Reduction in Revenues	60.7	59.5	70.7
Used	(57.1)	(67.4)	(82.5)
Balance at End of Year	28.4	24.8	32.7
Reduction in sales return reserve	$ (24.8)	$ (24.8)	$ (44.5)
Cumulative Effect, Period of Adoption, Adjustment
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Reduction in sales return reserve				$ 10.7