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Summary of Significant Accounting Policies - Summary of Cash, Cash Equivalents and Restricted Cash (Detail) - USD ($) $ in Thousands	Jun. 30, 2025	Sep. 30, 2024	Jun. 30, 2024	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Regulatory Assets [Line Items]
Cash and cash equivalents	$ 42,472	$ 15,621		$ 32,940
Restricted cash	$ 45,520	18,630	$ 19,285	36,072	$ 61,025	$ 123,867
Cash and Cash Equivalents [Member]
Regulatory Assets [Line Items]
Cash and cash equivalents		15,621		32,940
Restricted cash		3,009		3,132
Total cash, cash equivalents and restricted cash		$ 18,630		$ 36,072

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Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

+ References

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Amount of cash and cash equivalents, and cash and cash equivalents restricted to withdrawal or usage. Excludes amount for disposal group and discontinued operations. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Amount of cash and cash equivalents, and cash and cash equivalents restricted to withdrawal or usage; including, but not limited to, disposal group and discontinued operations. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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