Commitments and Contingencies - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended		24 Months Ended	57 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2010	Sep. 30, 2012	Jun. 10, 2011
Contingencies And Commitments [Line Items]
Certain Claims Selling General and Administrative Net						$ 388.2
Selling General and Administrative expenses	0	1.2	0	4.2
Certain claims				50.0
Estimated liability outstanding	229.7		229.7			229.7
Estimated liability classified as short-term	50.0		50.0			50.0
Estimated liability classified as long-term	179.7		179.7			179.7
Compensatory Damages Awarded					27.6
Percentage of Fault Apportioned to Plaintiffs					30.00%
Percentage of Fault Apportioned to Company					34.00%
Percentage of Fault Apportioned to Unrelated Third Party					36.00%
Verdict in full and entered judgment							$ 20.3