Net Sales - Disaggregation of Revenue (Details) $ in Millions	12 Months Ended
Dec. 31, 2022 USD ($) channel product_category	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Disaggregation of Revenue [Line Items]
Net sales	$ 4,921.2	$ 4,930.8	$ 3,676.9
Number of products sales channels \| channel	2
Number of product categories \| product_category	2
Royalty income, net of royalty expense	$ 31.8	29.1	21.9
Shipping and handling included in net sales	8.1	7.4	14.4
United States
Disaggregation of Revenue [Line Items]
Net sales			2,886.6
All Other
Disaggregation of Revenue [Line Items]
Net sales	1,325.2	1,179.5	790.3
Bedding
Disaggregation of Revenue [Line Items]
Net sales			3,353.8
Other
Disaggregation of Revenue [Line Items]
Net sales			323.1
Operating Segments
Disaggregation of Revenue [Line Items]
Net sales	4,921.2	4,930.8	3,676.9
Operating Segments \| Wholesale
Disaggregation of Revenue [Line Items]
Net sales	3,772.5	4,034.4	3,185.8
Operating Segments \| Direct
Disaggregation of Revenue [Line Items]
Net sales	1,148.7	896.4	491.1
Operating Segments \| United States
Disaggregation of Revenue [Line Items]
Net sales	3,596.0	3,751.3	2,886.6
Operating Segments \| All Other
Disaggregation of Revenue [Line Items]
Net sales	1,325.2	1,179.5	790.3
Operating Segments \| Bedding
Disaggregation of Revenue [Line Items]
Net sales	4,477.8	4,512.9	3,353.8
Operating Segments \| Other
Disaggregation of Revenue [Line Items]
Net sales	443.4	417.9	323.1
Operating Segments \| North America Segment
Disaggregation of Revenue [Line Items]
Net sales	3,886.1	4,079.2	3,159.2
Operating Segments \| North America Segment \| Wholesale
Disaggregation of Revenue [Line Items]
Net sales	3,390.1	3,584.1	2,806.7
Operating Segments \| North America Segment \| Direct
Disaggregation of Revenue [Line Items]
Net sales	496.0	495.1	352.5
Operating Segments \| North America Segment \| United States
Disaggregation of Revenue [Line Items]
Net sales	3,596.0	3,751.3	2,886.6
Operating Segments \| North America Segment \| All Other
Disaggregation of Revenue [Line Items]
Net sales	290.1	327.9	272.6
Operating Segments \| North America Segment \| Bedding
Disaggregation of Revenue [Line Items]
Net sales	3,618.7	3,825.9	2,956.3
Operating Segments \| North America Segment \| Other
Disaggregation of Revenue [Line Items]
Net sales	267.4	253.3	202.9
Operating Segments \| International Segment
Disaggregation of Revenue [Line Items]
Net sales	1,035.1	851.6	517.7
Operating Segments \| International Segment \| Wholesale
Disaggregation of Revenue [Line Items]
Net sales	382.4	450.3	379.1
Operating Segments \| International Segment \| Direct
Disaggregation of Revenue [Line Items]
Net sales	652.7	401.3	138.6
Operating Segments \| International Segment \| United States
Disaggregation of Revenue [Line Items]
Net sales	0.0	0.0	0.0
Operating Segments \| International Segment \| All Other
Disaggregation of Revenue [Line Items]
Net sales	1,035.1	851.6	517.7
Operating Segments \| International Segment \| Bedding
Disaggregation of Revenue [Line Items]
Net sales	859.1	687.0	397.5
Operating Segments \| International Segment \| Other
Disaggregation of Revenue [Line Items]
Net sales	$ 176.0	$ 164.6	$ 120.2