Severances And Related Costs (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Jun. 30, 2012	Mar. 31, 2011
Schedule Of Severances And Related Costs [Line Items]
Severance and related costs	$ 3.4
Positions eliminated	35
Cost Of Goods Sold [Member]
Schedule Of Severances And Related Costs [Line Items]
Severance and related costs	0.2	3.0
SG&A Expense [Member]
Schedule Of Severances And Related Costs [Line Items]
Severance and related costs	$ 3.2	$ 0.5

The charge against earnings in the period for known and estimated costs of termination benefits provided to current employees that are involuntarily terminated not related to a restructuring initiatives, excluding costs or losses pertaining to an entity newly acquired in a business combination or a discontinued operation as defined by generally accepted accounting principles and costs associated with one-time termination benefits.

No definition available.

Name:	awi_SeveranceAndRelatedCosts
Namespace Prefix:	awi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration