Litigation and Related Matters (Narrative) (Details) $ in Millions	1 Months Ended	12 Months Ended			36 Months Ended
	Sep. 30, 2010 Site	Dec. 31, 2021 USD ($) Site Litigation	Dec. 31, 2020 USD ($)	Dec. 31, 2007	Dec. 31, 2020 USD ($)
Loss Contingencies [Line Items]
Number of active and independent litigation matters for which pursuing coverage and recoveries | Litigation		2
Settlement agreement amount of litigation agreement		$ 0.5			$ 52.5
Environmental insurance recoveries received in excess of cumulative expenses incurred		4.8	$ 5.0		5.0
Environmental liabilities		0.7	1.2		1.2
Reserves for potential environmental liabilities		0.2	0.0
Accounts Payable and Accrued Expenses [Member]
Loss Contingencies [Line Items]
Environmental liabilities		$ 0.2	0.3		$ 0.3
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. 11, 2016
Elizabeth City [Member]
Loss Contingencies [Line Items]
Percentage of site costs Navy agreed to pay				33.33%
Cost of goods sold [Member]
Loss Contingencies [Line Items]
Settlement agreement amount of litigation agreement			9.2
SG&A Expenses [Member]
Loss Contingencies [Line Items]
Settlement agreement amount of litigation agreement			$ 38.3