Litigation and Related Matters (Narrative) (Details) $ in Millions	1 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended	60 Months Ended
	Sep. 30, 2010 Site	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($) Site	Sep. 30, 2021 USD ($)	Dec. 31, 2007	Dec. 31, 2021 USD ($)
Loss Contingencies [Line Items]
Settlement agreement amount of litigation agreement							$ 53.0
Environmental insurance recoveries received in excess of cumulative expenses incurred		$ 3.7		$ 3.7			4.8
Environmental liabilities		0.4		0.4			$ 0.7
Accrual for environmental loss contingencies, period increase (Decrease)		$ 0.0	$ 0.0	$ 0.6	$ 0.2
Accounts Payable and Accrued Expenses [Member]
Loss Contingencies [Line Items]
Environmental Loss Contingency, Statement of Financial Position [Extensible Enumeration]							Accounts Payable and Accrued Liabilities, Current
Environmental liabilities							$ 0.2
Other Long-Term Liabilities [Member]
Loss Contingencies [Line Items]
Environmental Loss Contingency, Statement of Financial Position [Extensible Enumeration]		Other Liabilities, Noncurrent		Other Liabilities, Noncurrent			Other Liabilities, Noncurrent
Environmental liabilities		$ 0.4		$ 0.4			$ 0.5
Macon Site [Member]
Loss Contingencies [Line Items]
Number of landfills listed as Superfund site | Site				2
Number of landfills AWI entered into an Administrative Order on Consent for a Removal Action | Site	1
Submission date of final report to EPA	Oct. 31, 2016
Elizabeth City [Member]
Loss Contingencies [Line Items]
Percentage of site costs Navy agreed to pay						33.33%