Borrowings - Schedule of Long-term Debt (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Sep. 30, 2015
Debt Instrument [Line Items]
Unamortized debt discounts	$ (4,819)	$ (3,639)
Total debt, net	1,429,483	1,528,275
Senior Notes
Debt Instrument [Line Items]
Unamortized debt discounts	(3,069)	(3,639)
Total debt, net	$ 1,234,249	$ 1,427,240
Senior Notes | 8 1/8% Senior Notes Maturing June 2016
Debt Instrument [Line Items]
Stated interest rate on debt instrument (percent)	8.125%	8.125%
Total debt, net	$ 0	$ 170,879
Senior Notes | 6 5/8% Senior Secured Notes April 2018
Debt Instrument [Line Items]
Stated interest rate on debt instrument (percent)	6.625%	6.625%
Total debt, net	$ 300,000	$ 300,000
Senior Notes | 9 1/8% Senior Notes Maturing May 2019
Debt Instrument [Line Items]
Stated interest rate on debt instrument (percent)	9.125%	9.125%
Total debt, net	$ 215,925	$ 235,000
Senior Notes | 5 3/4% Senior Notes Maturing June 2019
Debt Instrument [Line Items]
Stated interest rate on debt instrument (percent)	5.75%	5.75%
Total debt, net	$ 321,393	$ 325,000
Senior Notes | 7 1/2% Senior Notes Maturing September 2021
Debt Instrument [Line Items]
Stated interest rate on debt instrument (percent)	7.50%	7.50%
Total debt, net	$ 200,000	$ 200,000
Senior Notes | 7 1/4% Senior Notes Maturing February 2023
Debt Instrument [Line Items]
Stated interest rate on debt instrument (percent)	7.25%	7.25%
Total debt, net	$ 200,000	$ 200,000
Term Loan
Debt Instrument [Line Items]
Unamortized debt discounts	(1,750)
Total debt, net	$ 120,750	0
Junior Subordinated Notes
Debt Instrument [Line Items]
Stated interest rate on debt instrument (percent)	7.987%
Unamortized debt discounts	$ (41,420)	(42,970)
Total debt, net	59,353	57,803
Cash Secured Loans
Debt Instrument [Line Items]
Total debt, net	0	22,368
Other Secured Notes payable
Debt Instrument [Line Items]
Total debt, net	$ 15,131	$ 20,864