Effect of Revision on Previously Reported Amounts (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2012
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Effect of revision on net cash provided by (used in) operating activities, net	$ 9.6
Effect of revision on net cash provided by (used in) financing activities	(9.6)
Eliminations
Condensed Financial Statements, Captions [Line Items]
Effect of revision on net cash provided by (used in) operating activities, net	(9.6)
Effect of revision on net cash provided by (used in) financing activities	$ 9.6