Commitments and Contingencies Marshalltown Tornado and Recovery (Details) - USD ($) $ in Millions	3 Months Ended			12 Months Ended			18 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Insurance recoveries received for property damage incurred from natural disaster				$ 0.0	$ 79.6	$ 10.9
Loss(gain) from natural disaster, net of Insurance recoveries				(3.1)	178.8	38.3
Insurance Recoveries				0.0	243.2	124.3	$ 367.5
Write-off of property, plant and equipment						4.0
Gain from insurance recoveries, net of losses incurred	$ 93.4	$ 7.1	$ 31.9		46.4
Loss Contingencies [Line Items]
Loss(gain) from natural disaster, net of Insurance recoveries				3.1	(178.8)	(38.3)
Insurance recoveries received				0.0	243.2	124.3	$ 367.5
Write-off of property, plant and equipment						4.0
Gain from insurance recoveries, net of losses incurred	$ 93.4	$ 7.1	$ 31.9		46.4
Insurance recoveries received for property damage incurred from natural disaster				0.0	79.6	10.9
Marshalltown Tornado [Member]
Commitments and Contingencies Disclosure [Abstract]
Insurance recoveries received for property damage incurred from natural disaster				3.0	(79.6)	(10.9)
Loss(gain) from natural disaster, net of Insurance recoveries				(3.0)	178.8	38.3
Insurance Recoveries				0.0	243.2	124.3
Write-off of inventory				0.0	0.0	5.8
Write-off of property, plant and equipment				0.0	0.0	4.2
Factory inefficiencies				0.0	9.3	7.4
Gain from insurance recoveries, net of losses incurred				3.0	(178.8)	(38.3)
Insurance proceeds for lost profits				0.0	(99.2)	(27.4)
Loss Contingencies [Line Items]
Loss(gain) from natural disaster, net of Insurance recoveries				3.0	(178.8)	(38.3)
Insurance recoveries received				0.0	243.2	124.3
Write-off of inventory				0.0	0.0	5.8
Write-off of property, plant and equipment				0.0	0.0	4.2
Factory inefficiencies				0.0	9.3	7.4
Gain from insurance recoveries, net of losses incurred				3.0	(178.8)	(38.3)
Insurance proceeds for lost profits				0.0	(99.2)	(27.4)
Insurance recoveries received for property damage incurred from natural disaster				3.0	(79.6)	(10.9)
Site clean-up and remediation				0.0	20.4	50.9
Other Nonrecurring Expense				3.0	34.7	17.7
Total expense due to natural disaster				3.0	64.4	86.0
Marshalltown Wind Storm [Member]
Commitments and Contingencies Disclosure [Abstract]
Loss(gain) from natural disaster, net of Insurance recoveries				(0.1)	0.0	0.0
Insurance Recoveries				6.6
Write-off of inventory				0.1
Building And Building Improvement				3.0
Factory inefficiencies				0.2
Loss Contingencies [Line Items]
Loss(gain) from natural disaster, net of Insurance recoveries				0.1	$ 0.0	$ 0.0
Insurance recoveries received				6.6
Write-off of inventory				0.1
Building And Building Improvement				3.0
Factory inefficiencies				0.2
Site clean-up and remediation				1.7
Other Nonrecurring Expense				1.7
Total expense due to natural disaster				$ 6.7