Borrowings - Schedule of Long-term Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Sep. 30, 2025
Debt Instrument [Line Items]
Total outstanding borrowings of unconsolidated entities	$ 1,125,055	$ 1,029,114
Unamortized debt issuance costs	(6,187)	(6,611)
Senior Unsecured Revolving Credit Facility
Debt Instrument [Line Items]
Senior Unsecured Revolving Credit Facility	95,000	0
Senior Notes
Debt Instrument [Line Items]
Total outstanding borrowings of unconsolidated entities	951,068	950,644
Unamortized debt issuance costs	$ (6,187)	$ (6,611)
Senior Notes | 5.875%
Debt Instrument [Line Items]
Stated interest rate on debt instrument	5.875%	5.875%
Total outstanding borrowings of unconsolidated entities	$ 357,255	$ 357,255
Senior Notes | 7.250%
Debt Instrument [Line Items]
Stated interest rate on debt instrument	7.25%	7.25%
Total outstanding borrowings of unconsolidated entities	$ 350,000	$ 350,000
Senior Notes | 7.500%
Debt Instrument [Line Items]
Stated interest rate on debt instrument	7.50%	7.50%
Total outstanding borrowings of unconsolidated entities	$ 250,000	$ 250,000
Junior Subordinated Notes
Debt Instrument [Line Items]
Unamortized accretion	21,786	22,303
Total outstanding borrowings of unconsolidated entities	$ 78,987	$ 78,470