Long-term Debt (Details 5) (USD $)	3 Months Ended		6 Months Ended			1 Months Ended	3 Months Ended	6 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012	Mar. 31, 2011	Sep. 30, 2011	Mar. 31, 2011 11-3/8% senior secured notes	Mar. 31, 2011 11-3/8% senior secured notes	Mar. 31, 2011 11-3/8% senior secured notes
Long-term Debt
Interest expense	$ 13,500,000	$ 82,700,000	$ 26,100,000	$ 99,600,000
Non-cash interest expense	2,800,000	11,200,000	5,863,000	14,496,000
Capitalized interest costs			100,000	0
Interest income	0	100,000	100,000	100,000
Weighted average interest rate (as a percent)	6.70%		6.70%		6.80%
Long-term debt
Debt instrument prepayment premium						$ 59,000,000	$ 59,000,000	$ 59,000,000