Effect of Revision on Previously Reported Amounts (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2012
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Effect of revision on net cash provided by (used in) operating activities, net	$ 10.5
Effect of revision on net cash provided by (used in) financing activities	(10.5)
Eliminations
Condensed Financial Statements, Captions [Line Items]
Effect of revision on net cash provided by (used in) operating activities, net	(10.5)
Effect of revision on net cash provided by (used in) financing activities	$ 10.5