Long-term Debt (Details 2) (USD $) In Millions, unless otherwise specified	9 Months Ended	12 Months Ended		9 Months Ended			1 Months Ended	9 Months Ended		9 Months Ended
	Jun. 30, 2014 Senior Secured Notes7.625 Percent Due April2019 [Member]	Sep. 30, 2011 Senior Secured Notes7.625 Percent Due April2019 [Member]	Sep. 30, 2013 Senior Secured Notes7.625 Percent Due April2019 [Member]	Jun. 30, 2014 Senior Secured Notes7.625 Percent Due April2019 [Member] Debt Instrument Redemption Period Commencing After March312015 [Member] Maximum [Member]	Jun. 30, 2014 Senior Secured Notes7.625 Percent Due April2019 [Member] Debt Instrument Redemption Period Commencing After March312015 [Member] Minimum [Member]	Jun. 30, 2014 Senior Secured Notes7.625 Percent Due April2019 [Member] Debt Instrument Redemption Period On Or Prior To March312015 [Member]	Dec. 31, 2013 Senior Notes7.25 Percent Due January2019 [Member]	Jun. 30, 2014 Senior Notes7.25 Percent Due January2019 [Member]	Sep. 30, 2013 Senior Notes7.25 Percent Due January2019 [Member]	Jun. 30, 2014 Senior Notes7.25 Percent Due January2019 [Member] Debt Instrument Redemption Period Commencing After January152016 [Member] Maximum [Member]	Jun. 30, 2014 Senior Notes7.25 Percent Due January2019 [Member] Debt Instrument Redemption Period Commencing After January152016 [Member] Minimum [Member]	Jun. 30, 2014 Senior Notes7.25 Percent Due January2019 [Member] Debt Instrument Redemption Period On Or Prior To January152016 [Member]	Jun. 30, 2014 Senior Notes7.25 Percent Due January2019 [Member] Debt Instrument Redemption Period On Or Prior To January152016 [Member] Maximum [Member]
Long-term debt
Additional borrowings		$ 400.0					$ 150.0
Net proceeds from senior secured notes		$ 392.8					$ 146.2
Interest rate on secured notes (as a percent)	7.625%	7.625%	7.625%				7.25%	7.25%	7.25%
Debt instrument redemption price (as a percent)				103.80%	100.00%					103.625%	100.00%
Percentage of the principal amount of the debt instrument which the entity may redeem with proceeds from qualified equity offerings													35.00%
Redemption price of debt instrument if redeemed with proceeds from qualified equity offerings (as a percent)												107.25%
Debt instrument redemption price in addition to a make-whole premium (as a percent)						100.00%						100.00%
Purchase price of debt instrument, if there is a change in control (as a percent)	101.00%							101.00%