Borrowings - Schedule of Long-term Debt (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Sep. 30, 2012	Mar. 31, 2013 Senior Notes	Sep. 30, 2012 Senior Notes	Jul. 17, 2012 Senior Notes Tangible Equity Units	May 31, 2010 Senior Notes Tangible Equity Units	Mar. 31, 2013 Senior Notes 6 7/8% Senior Notes Maturing July 2015	Sep. 30, 2012 Senior Notes 6 7/8% Senior Notes Maturing July 2015	Mar. 31, 2013 Senior Notes 8 1/8% Senior Notes Maturing June 2016	Sep. 30, 2012 Senior Notes 8 1/8% Senior Notes Maturing June 2016	Mar. 31, 2013 Senior Notes 6 5/8% Senior Secured Notes	Sep. 30, 2012 Senior Notes 6 5/8% Senior Secured Notes	Mar. 31, 2013 Senior Notes 9 1/8% Senior Notes Maturing June 2018	Sep. 30, 2012 Senior Notes 9 1/8% Senior Notes Maturing June 2018	Mar. 31, 2013 Senior Notes 9 1/8% Senior Notes Maturing May 2019	Sep. 30, 2012 Senior Notes 9 1/8% Senior Notes Maturing May 2019	Mar. 31, 2013 Senior Notes TEU Senior Amortizing Notes	Sep. 30, 2012 Senior Notes TEU Senior Amortizing Notes	Mar. 31, 2013 Senior Notes TEU Senior Amortizing Notes	Sep. 30, 2012 Senior Notes TEU Senior Amortizing Notes	Mar. 31, 2013 Senior Notes 7 1/4% Senior Notes Maturing February 2023 [Member]	Feb. 01, 2013 Senior Notes 7 1/4% Senior Notes Maturing February 2023 [Member]	Sep. 30, 2012 Senior Notes 7 1/4% Senior Notes Maturing February 2023 [Member]	Mar. 31, 2013 Convertible Subordinated Debt	Sep. 30, 2012 Convertible Subordinated Debt	Mar. 31, 2013 Junior Subordinated Notes	Sep. 30, 2012 Junior Subordinated Notes	Mar. 31, 2013 Cash Secured Loan	Sep. 30, 2012 Cash Secured Loan	Mar. 31, 2013 Other Secured Notes Payable	Sep. 30, 2012 Other Secured Notes Payable
Debt Instrument [Line Items]
Debt instrument stated interest rate (percent)					7.50%	7.25%	6.875%	6.875%	8.125%	8.125%	6.625%	6.625%	9.125%	9.125%	9.125%	9.125%					7.25%	7.25%	0.00%			7.987%
Senior notes							$ 0	$ 172,454	$ 172,879	$ 172,879	$ 300,000	$ 300,000	$ 298,000	$ 300,000	$ 235,000	$ 235,000	$ 161	$ 316	$ 19,885	$ 23,500	$ 200,000		$ 0
Unamortized debt discounts	(2,440)	(3,082)	(2,440)	(3,082)																						48,100
Long-term debt	$ 1,507,153	$ 1,498,198	$ 1,223,485	$ 1,201,067																				$ 0	$ 9,402	$ 52,637	$ 51,603	$ 222,368	$ 227,368	$ 8,663	$ 8,758