Borrowings - Schedule of Debt Redemption (Details) - Senior Notes	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Feb. 01, 2013
8 1/8% Senior Notes Maturing June 2016
Debt Instrument, Redemption [Line Items]
Debt instrument stated interest rate (percent)	8.125%	8.125%
6 5/8% Senior Secured Notes Maturing April 2018
Debt Instrument, Redemption [Line Items]
Debt instrument stated interest rate (percent)	6.625%	6.625%
6 5/8% Senior Secured Notes Maturing April 2018 | Debt Instrument, Redemption, Period One
Debt Instrument, Redemption [Line Items]
Debt Instrument, Redemption Price, Percentage	103.313%
6 5/8% Senior Secured Notes Maturing April 2018 | Debt Instrument, Redemption, Period Two
Debt Instrument, Redemption [Line Items]
Debt Instrument, Redemption Price, Percentage	101.656%
9 1/8% Senior Notes Maturing May 2019
Debt Instrument, Redemption [Line Items]
Debt instrument stated interest rate (percent)	9.125%	9.125%
9 1/8% Senior Notes Maturing May 2019 | Debt Instrument, Redemption, Period One
Debt Instrument, Redemption [Line Items]
Debt Instrument, Redemption Price, Percentage	104.563%
9 1/8% Senior Notes Maturing May 2019 | Debt Instrument, Redemption, Period Two
Debt Instrument, Redemption [Line Items]
Debt Instrument, Redemption Price, Percentage	102.281%
7 1/2% Senior Notes Maturing September 2021
Debt Instrument, Redemption [Line Items]
Debt instrument stated interest rate (percent)	7.50%	7.50%
7 1/2% Senior Notes Maturing September 2021 | Debt Instrument, Redemption, Period One
Debt Instrument, Redemption [Line Items]
Debt Instrument, Redemption Price, Percentage	100.00%
7 1/2% Senior Notes Maturing September 2021 | Debt Instrument, Redemption, Period Two
Debt Instrument, Redemption [Line Items]
Debt Instrument, Redemption Price, Percentage	105.625%
7 1/2% Senior Notes Maturing September 2021 | Debt Instrument, Redemption, Period Three
Debt Instrument, Redemption [Line Items]
Debt Instrument, Redemption Price, Percentage	103.75%
7 1/2% Senior Notes Maturing September 2021 | Debt Instrument, Redemption, Period Four
Debt Instrument, Redemption [Line Items]
Debt Instrument, Redemption Price, Percentage	101.875%
7 1/4% Senior Notes Maturing February 2023
Debt Instrument, Redemption [Line Items]
Debt instrument stated interest rate (percent)	7.25%	7.25%	7.25%
7 1/4% Senior Notes Maturing February 2023 | Debt Instrument, Redemption, Period One
Debt Instrument, Redemption [Line Items]
Debt Instrument, Redemption Price, Percentage	100.00%
7 1/4% Senior Notes Maturing February 2023 | Debt Instrument, Redemption, Period Two
Debt Instrument, Redemption [Line Items]
Debt Instrument, Redemption Price, Percentage	103.625%
7 1/4% Senior Notes Maturing February 2023 | Debt Instrument, Redemption, Period Three
Debt Instrument, Redemption [Line Items]
Debt Instrument, Redemption Price, Percentage	102.41%
7 1/4% Senior Notes Maturing February 2023 | Debt Instrument, Redemption, Period Four
Debt Instrument, Redemption [Line Items]
Debt Instrument, Redemption Price, Percentage	101.208%