Accounts Receivable Securitization Program - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2012		Dec. 31, 2011
Maximum purchase limit for receivable interests under Accounts Receivable Securitization Program	$ 125
Accounts receivable securitization program expiration date	2012-12
Accounts receivable securitization program extended maturity period	2013-09
Amount available for accounts receivable securitization program	118.0	[1]	92.0	[1]
Level of eligible assets available under accounts receivable securitization program	Less than $125 million
Amount outstanding under accounts receivable securitization program	$ 0		$ 0

[1] See Note 9, "Accounts Receivable Securitization Program," for further details of this program.