Summary of Significant Accounting Policies (Details) $ in Millions	3 Months Ended
	Mar. 31, 2020 USD ($) channel	Jan. 01, 2020 USD ($)	Dec. 31, 2019 USD ($)
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Number of products sales channels | channel	2
Ownership percentage	50.00%
Net investment	$ 22.1		$ 22.5
Effect of adoption of accounting principle		$ 6.5
Retained Earnings
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Effect of adoption of accounting principle		6.5
Retained Earnings | Accounting Standards Update 2016-13
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Effect of adoption of accounting principle		$ 6.5
Accrued expenses and other current liabilities
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Accrued sales returns	25.0		26.2
Warranty Term [Abstract]
Accrued warranty expense	19.1		19.4
Other noncurrent liabilities
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Accrued sales returns	13.4		13.1
Warranty Term [Abstract]
Accrued warranty expense	$ 22.2		$ 22.2
Mattresses | Non-prorated | International
Warranty Term [Abstract]
Warranty term (in years)	5 years
Mattresses | Prorated | International
Warranty Term [Abstract]
Warranty term (in years)	10 years
Mattresses | Minimum | North America
Warranty Term [Abstract]
Warranty term (in years)	10 years
Mattresses | Minimum | International
Warranty Term [Abstract]
Warranty term (in years)	5 years
Mattresses | Minimum | Non-prorated | North America
Warranty Term [Abstract]
Warranty term (in years)	10 years
Mattresses | Maximum | North America
Warranty Term [Abstract]
Warranty term (in years)	25 years
Mattresses | Maximum | International
Warranty Term [Abstract]
Warranty term (in years)	15 years
Mattresses | Maximum | Non-prorated | North America
Warranty Term [Abstract]
Warranty term (in years)	15 years
Pillows | North America
Warranty Term [Abstract]
Warranty term (in years)	3 years