Contractual interest rate for funds borrowed, under the debt agreement.

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Borrowings - Schedule of Long-term Debt (Details) - USD ($)	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019	Oct. 31, 2017	Mar. 31, 2017
Debt Instrument [Line Items]
Unamortized debt issuance costs	$ (8,983,000)	$ (10,891,000)
Total debt, net	1,054,030,000	1,130,801,000
Revolving Credit Facility
Debt Instrument [Line Items]
Revolving Credit Facility	0	0
Senior Notes
Debt Instrument [Line Items]
Senior Unsecured Term Loan	50,000,000	100,000,000
Unamortized debt issuance costs	(8,983,000)	(10,891,000)
Total debt, net	983,827,000	1,062,664,000
Junior Subordinated Notes
Debt Instrument [Line Items]
Total debt, net	70,203,000	68,137,000
Unamortized discount	30,570,000	32,636,000
6 3/4% Senior Notes (2025 Notes) \| Senior Notes
Debt Instrument [Line Items]
Total debt, net	229,555,000	229,555,000
5 7/8% Senior Notes (2027 Notes) \| Senior Notes
Debt Instrument [Line Items]
Total debt, net	363,255,000	394,000,000
7 1/4% Senior Notes (2029 Notes) \| Senior Notes
Debt Instrument [Line Items]
Total debt, net	$ 350,000,000	$ 350,000,000
Senior Notes \| 6 3/4% Senior Notes (2025 Notes)
Debt Instrument [Line Items]
Stated interest rate on debt instrument	6.75%				0.0675%
Senior Notes \| 5 7/8% Senior Notes (2027 Notes)
Debt Instrument [Line Items]
Stated interest rate on debt instrument	5.88%			0.0588%
Senior Notes \| 7 1/4% Senior Notes (2029 Notes)
Debt Instrument [Line Items]
Stated interest rate on debt instrument	7.25%		0.0725%
Junior Subordinated Notes
Debt Instrument [Line Items]
Unamortized discount	$ 30,600,000