Guarantor and Non-Guarantor Subsidiaries Financial Information - Additional Information (Detail)	6 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
13.75% Holdings Notes due 2019
Parent Company Only Financial Information [Line Items]
Interest rate	13.75%
Due date of Senior Secured Notes	2019
6.00% Senior Secured Notes
Parent Company Only Financial Information [Line Items]
Interest rate	6.00%	6.00%
Due date of Senior Secured Notes	2021
6.25% Senior Secured Notes
Parent Company Only Financial Information [Line Items]
Interest rate	6.25%	6.25%
Due date of Senior Secured Notes	2021
11.5% Senior Notes due 2018
Parent Company Only Financial Information [Line Items]
Interest rate	11.50%
Due date of Senior Secured Notes	2018