Revenue - By Major Source (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Net sales	$ 1,144.9	$ 1,239.3	$ 1,213.2	$ 1,155.1	$ 1,046.7	$ 1,091.5	$ 1,102.5	$ 1,028.8	$ 4,752.5	$ 4,269.5	$ 3,943.8
Residential Products
Disaggregation of Revenue [Line Items]
Net sales									2,331.0	1,703.7	1,620.2
Residential Products | Bedding group
Disaggregation of Revenue [Line Items]
Net sales									1,502.0	905.1	837.2
Residential Products | Fabric & Flooring Products group
Disaggregation of Revenue [Line Items]
Net sales									776.4	735.8	720.1
Residential Products | Machinery group
Disaggregation of Revenue [Line Items]
Net sales									52.6	62.8	62.9
Industrial Products
Disaggregation of Revenue [Line Items]
Net sales									295.6	367.4	291.7
Industrial Products | Wire group
Disaggregation of Revenue [Line Items]
Net sales									295.6	367.4	291.7
Furniture Products
Disaggregation of Revenue [Line Items]
Net sales									1,059.1	1,142.1	1,096.4
Furniture Products | Consumer Products group
Disaggregation of Revenue [Line Items]
Net sales									404.6	460.2	413.3
Furniture Products | Home Furniture group
Disaggregation of Revenue [Line Items]
Net sales									357.2	388.6	410.2
Furniture Products | Work Furniture group
Disaggregation of Revenue [Line Items]
Net sales									297.3	293.3	272.9
Specialized Products
Disaggregation of Revenue [Line Items]
Net sales									1,066.8	1,056.3	935.5
Specialized Products | Automotive group
Disaggregation of Revenue [Line Items]
Net sales									816.1	823.3	772.5
Specialized Products | Aerospace Products group
Disaggregation of Revenue [Line Items]
Net sales									157.7	148.9	137.9
Specialized Products | Hydraulic Cylinders group
Disaggregation of Revenue [Line Items]
Net sales									93.0	84.1	0.0
Specialized Products | Commercial Vehicle Products (CVP) group
Disaggregation of Revenue [Line Items]
Net sales									$ 0.0	$ 0.0	$ 25.1