Impairment Charges (Components of Fair Values In Relation to Their Respective Carrying Values) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2023	Dec. 31, 2022	Jun. 30, 2023	Jun. 30, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill value	$ 1,489.8	$ 1,489.8	$ 1,474.4
Terminal Values Long-term Growth Rate for Debt-Free Cash Flow	3.00%	3.00%	3.00%
Less than 50%
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill value	$ 1,018.1	$ 1,018.1	$ 107.8
Terminal Values Long-term Growth Rate for Debt-Free Cash Flow	3.00%	3.00%	3.00%
Discount Rate Ranges			12.00%
50-100%
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill value	$ 99.6	$ 99.6	$ 998.7
Compound Annual Growth Rate Range for Sales		1.00%
Terminal Values Long-term Growth Rate for Debt-Free Cash Flow	3.00%	3.00%	3.00%
Discount Rate Ranges		8.00%	10.00%
101-300%
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill value	$ 372.1	$ 372.1	$ 248.3
Terminal Values Long-term Growth Rate for Debt-Free Cash Flow	3.00%	3.00%	3.00%
Discount Rate Ranges			10.00%
Greater than 300%
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value over Carrying Value divided by Carrying Value			300.00%
Goodwill value			$ 119.6
Compound Annual Growth Rate Range for Sales			8.00%
Terminal Values Long-term Growth Rate for Debt-Free Cash Flow			3.00%
Discount Rate Ranges			12.00%
Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Compound Annual Growth Rate Range for Sales		1.00%	1.00%
Discount Rate Ranges		8.00%	10.00%
Minimum | Less than 50%
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Compound Annual Growth Rate Range for Sales		1.00%	4.00%
Discount Rate Ranges		10.00%
Minimum | 50-100%
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value over Carrying Value divided by Carrying Value		50.00%	50.00%
Compound Annual Growth Rate Range for Sales			3.00%
Minimum | 101-300%
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value over Carrying Value divided by Carrying Value		101.00%	101.00%
Compound Annual Growth Rate Range for Sales		3.00%	1.00%
Discount Rate Ranges		8.00%
Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Compound Annual Growth Rate Range for Sales		17.00%	9.00%
Discount Rate Ranges		12.00%	12.00%
Maximum | Less than 50%
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value over Carrying Value divided by Carrying Value		50.00%	50.00%
Compound Annual Growth Rate Range for Sales		17.00%	9.00%
Discount Rate Ranges		12.00%
Maximum | 50-100%
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value over Carrying Value divided by Carrying Value		100.00%	100.00%
Compound Annual Growth Rate Range for Sales			5.00%
Maximum | 101-300%
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value over Carrying Value divided by Carrying Value		300.00%	300.00%
Compound Annual Growth Rate Range for Sales		6.00%	3.00%
Discount Rate Ranges		10.00%
Bedding
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill value	$ 906.5	$ 906.5	$ 900.3
Compound Annual Growth Rate Range for Sales	2.00%
Discount Rate Ranges	10.00%
Fair value in excess of carrying value for the goodwill impairment testing performed (as a percent)	19.00%	19.00%		40.00%	54.00%
Work Furniture
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill value	$ 99.6	$ 99.6	98.4
Fair value in excess of carrying value for the goodwill impairment testing performed (as a percent)				74.00%	78.00%
Aerospace Products
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill value	67.0	67.0	66.3
Fair value in excess of carrying value for the goodwill impairment testing performed (as a percent)				44.00%	40.00%
Hydraulic Cylinders
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill value	$ 44.6	$ 44.6	$ 41.5
Fair value in excess of carrying value for the goodwill impairment testing performed (as a percent)				18.00%	32.00%