Retirement Plans - Defined Benefit Plans (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($) facility	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Retirement plans
Number of active plants at which a defined benefit pension plan for current and former hourly employees is provided | facility	2
Number of previously closed U.S. facilities at which a defined benefit pension plan for current and former hourly employees was provided | facility	10
Components of net periodic pension cost for employees
Service cost	$ 0.9	$ 1.0	$ 0.9
Interest cost	1.2	1.1	1.2
Expected return on assets	(1.3)	(1.5)	(1.5)
Amortization of prior service cost	0.1	0.1	0.1
Amortization of net gain	0.1	0.0	0.0
Net periodic pension cost	1.0	0.7	0.7
Other changes in plan assets and benefit obligations recognized in accumulated other comprehensive income
Net loss	2.2	0.6	0.4
New prior service cost	0.6	0.1	0.5
Amortization of prior service cost	(0.1)	(0.1)	(0.1)
Amortization or settlement recognition of net loss	(0.1)	0.0	0.0
Total recognized in other comprehensive loss	$ 2.6	$ 0.6	$ 0.8
Assumptions, calculated on a weighted-average basis, were used to determine pension costs
Discount rate (as a percent)	4.10%	3.58%	4.07%
Expected long term return on plan assets (as a percent)	6.16%	6.25%	6.64%
Change in Benefit Obligation:
Projected benefit obligation at beginning of year	$ 30.0	$ 32.1
Service cost	0.9	1.0	$ 0.9
Interest cost	1.2	1.1	1.2
Plan amendments	0.5	0.1
Actuarial (gain) loss	5.5	(3.0)
Benefits paid	(1.3)	(0.9)
Expenses paid	(0.1)	(0.1)
Foreign currency exchange rate changes	0.2	(0.3)
Projected benefit obligation at end of year	36.9	30.0	32.1
Change in Plan Assets:
Fair value of plan assets at beginning of year	22.2	25.3
Actual return on plan assets	4.6	(2.1)
Employer contribution	1.4	0.3
Benefits paid	(1.3)	(0.9)
Expenses paid	(0.1)	(0.1)
Foreign currency exchange rate changes	0.2	(0.3)
Fair value of plan assets at end of year	27.0	22.2	$ 25.3
Funded status	(9.9)	(7.8)
Amounts recognized in the Consolidated Balance Sheets:
Non-current benefit liability	10.0	8.1
Non-current benefit asset	$ 0.1	$ 0.3
Assumptions, calculated on a weighted-average basis, were used to determine benefit obligations
Discount rate (percentage)	3.16%	4.13%
United States Retirement Plan
Assumptions, calculated on a weighted-average basis, were used to determine pension costs
Discount rate (as a percent)	4.16%	3.54%	4.06%
Assumptions, calculated on a weighted-average basis, were used to determine benefit obligations
Discount rate (percentage)	3.15%	4.16%
Canadian Retirement Plan
Assumptions, calculated on a weighted-average basis, were used to determine pension costs
Discount rate (as a percent)	3.90%	3.70%	4.10%
Assumptions, calculated on a weighted-average basis, were used to determine benefit obligations
Discount rate (percentage)	3.20%	3.90%
Sealy
Retirement plans
Number of facilities where employees are covered by defined benefit pension plan | facility	1
Sealy | United States Retirement Plan
Change in Benefit Obligation:
Projected benefit obligation at beginning of year	$ 26.5
Projected benefit obligation at end of year	32.6	$ 26.5
Change in Plan Assets:
Fair value of plan assets at beginning of year	18.4
Fair value of plan assets at end of year	22.6	18.4
Sealy | Canadian Retirement Plan
Change in Benefit Obligation:
Projected benefit obligation at beginning of year	3.5
Projected benefit obligation at end of year	4.3	3.5
Change in Plan Assets:
Fair value of plan assets at beginning of year	3.8
Fair value of plan assets at end of year	$ 4.4	$ 3.8