Long-term Debt (Details) (USD $)	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 Senior Secured Notes 7.625 Percent Due April 2019	Sep. 30, 2013 Senior Secured Notes 7.625 Percent Due April 2019	Sep. 30, 2011 Senior Secured Notes 7.625 Percent Due April 2019	Sep. 30, 2014 Senior Notes 7.25 Percent Due January 2019	Dec. 31, 2013 Senior Notes 7.25 Percent Due January 2019	Sep. 30, 2013 Senior Notes 7.25 Percent Due January 2019	Sep. 30, 2014 Convertible Subordinated Debt	Sep. 30, 2013 Convertible Subordinated Debt	Sep. 30, 2014 Convertible Senior Subordinated Notes 2.50 Percent Due 2014	Sep. 30, 2013 Convertible Senior Subordinated Notes 2.50 Percent Due 2014	Sep. 30, 2014 Convertible Senior Subordinated Notes 8.75 Percent Due 2016	Sep. 30, 2013 Convertible Senior Subordinated Notes 8.75 Percent Due 2016	Sep. 30, 2012 Convertible Senior Subordinated Notes 8.75 Percent Due 2016
Long-term debt
Debt instrument, face amount	$ 599,800,000	$ 457,500,000										$ 7,687,000	$ 49,791,000	$ 49,791,000
Carrying amount of long-term debt, net of discounts	599,579,000	456,973,000	400,000,000	400,000,000		150,000,000		0	49,579,000	56,973,000	0	7,553,000	49,579,000	49,420,000
Less current portion	0	(7,553,000)
Long-term debt	$ 599,579,000	$ 449,420,000
Interest rate on long-term debt (as a percent)			7.625%	7.625%	7.625%	7.25%	7.25%				2.50%	2.50%	8.75%	8.75%	8.75%