Litigation (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2012 homes
Litigation (Textual) [Abstract]
Loss Contingency, Estimate of Possible Loss	$ 8
Approximate number of property damage claims resolved	250
Homeowners opted out of class action settlement	10
Receivables Related to Settlement	4
Accrual potential liability for environmental cleanup	$ 12
Approximate number of homes where the presence of Knauf Tianjin wallboard has been confirmed	290
Minimum [Member]
Litigation (Textual) [Abstract]
Range of average-size houses that the amount of Knauf Tianjin wallboard potentially sold by L&W Supply Corporation could completely furnish	250
Maximum [Member]
Litigation (Textual) [Abstract]
Range of average-size houses that the amount of Knauf Tianjin wallboard potentially sold by L&W Supply Corporation could completely furnish	300