Transactions with Controlled Companies - QC Holdings TopCo, LLC (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Sep. 30, 2026	Sep. 30, 2025	Jun. 30, 2026
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Interest Income	$ 132,608	$ 152,394
Interest Receivable	23,039		$ 17,350
Subsidiaries \| Reportable Legal Entities \| QC Holdings TopCo, LLC
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Interest Income	3,482	3,374
Additions	3,430	1,706
Interest Receivable	40	40
Other Receivables	(119)	(122)
Subsidiaries \| Reportable Legal Entities \| QC Holdings TopCo, LLC \| Prospect Administration
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Managerial Assistance	163	163
Reimbursement of Legal, Tax, etc	$ 20	$ 269
QC Holdings TopCo, LLC
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Ownership interest	95.40%		95.40%

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