Contingencies - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	1 Months Ended		9 Months Ended	1 Months Ended
	Jun. 30, 2012	Jul. 31, 2012	Jul. 31, 2012 Augustus	May 31, 2012 Superior Court	Mar. 14, 2012 Khadera	Mar. 14, 2012 Simpson	Apr. 06, 2011 Las and Yanez	May 17, 2012 Bojorquez
Loss Contingencies [Line Items]
Loss contingency amount accrued for probable losses		$ 6.9
Range of loss for all reasonably possible losses, minimum		0
Range of loss for all reasonably possible losses, maximum		92.3
Possible contingency losses			89.7
Break claim which seeks damages			103.0
Payment to plaintiffs			89.7
Settlement made				3.2
Gross litigation settlement value					1.8	1.2	2.1
Agreement settlement date for litigation							May 4, 2012
Gross settlement value percentage							100.00%
Proposed gross settlement value							5.5
Gross settlement value percentage							30.00%
Gross litigation settlement value, maximum							2.9
The jury awarded the plaintiff in damages for suit filed								0.8
Payment to other party in for settlement	$ 1.8