Securitization - Maturities of the Securitized Long-term Debt and Amortization Expense to the Securitized Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Sep. 30, 2024
Maturities of Securitized Long-Term Debt
2026	$ 10,000
2027	500,000
2028	150,000
2029	500,000
2030	0
Thereafter	7,775,000
Amortization Expense of Securitized Intangible Asset
Total	75,127	$ 82,844
Variable Interest Entity, Primary Beneficiary
Maturities of Securitized Long-Term Debt
2026	8,767
2027	9,086
2028	9,561
2029	10,060
2030	10,585
Thereafter	28,944
Total	77,003
Amortization Expense of Securitized Intangible Asset
2026	8,555
2027	9,001
2028	9,471
2029	9,966
2030	10,486
Thereafter	27,648
Total	$ 75,127	$ 82,844