Stock-Based Compensation Plans - Schedule of Stock Option Activity (Detail) (USD $)	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Shares Outstanding, Beginning balance	1,325,438	1,515,188	1,492,321
Number of Shares, Granted	178,924	299,832	551,773
Number of Shares, Exercised	(10,273)	(11,379)	0
Number of Shares, Forfeited	(125,105)	(478,203)	(528,906)
Number of Shares Outstanding, Ending balance	1,368,984	1,325,438	1,515,188
Number of Shares, Exercisable	771,640
Weighted Average Exercise Price, Beginning Balance	$ 21.25	$ 25.59	$ 31.22
Weighted Average Exercise Price, Granted	$ 20.85	$ 12.46	$ 9.96
Weighted Average Exercise Price, Exercised	$ 14.40	$ 10.03
Weighted Average Exercise Price, Forfeited	$ 33.47	$ 29.76	$ 25.15
Weighted Average Exercise Price, Ending balance	$ 20.13	$ 21.25	$ 25.59
Weighted Average Exercise Price, Exercisable	$ 24.47