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Transactions with Controlled Companies - MITY, Inc. (Details) - USD ($) $ in Thousands	3 Months Ended			12 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Dec. 31, 2016	Jun. 30, 2026
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Interest Income	$ 132,608	$ 152,394
Structuring Fee	10,605	1,299
Total Other Income	13,658	1,657
Realized (Loss) Gain	(71,607)	(1,891)
Interest Receivable	$ 23,039			$ 17,350
MITY, Inc. \| MITY Holdings of Delaware Inc.
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Ownership interest	100.00%			100.00%
MITY-Lite, Inc. \| MITY, Inc.
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Ownership interest	100.00%			100.00%
Broda USA, Inc. \| MITY, Inc.
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Ownership interest	100.00%			100.00%
Broda Enterprises ULC \| MITY, Inc.
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Ownership interest	100.00%			100.00%
Reportable Legal Entities \| Subsidiaries \| MITY, Inc.
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Interest Income	$ 2,321	2,380
Structuring Fee	50	0
Total Other Income	50	0
Realized (Loss) Gain	6	5
Additions	2,015	0
Interest Receivable	25			$ 27
Other Receivables	17			$ 2
Reportable Legal Entities \| Subsidiaries \| MITY, Inc. \| Prospect Administration
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Managerial Assistance	$ 113	113
Reportable Legal Entities \| Subsidiaries \| MITY Holdings of Delaware Inc.
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Ownership interest	100.00%			100.00%
Reportable Legal Entities \| Subsidiaries \| MITY, Inc. \| MITY, Inc.
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Interest Income	$ 2,192	2,380
Reportable Legal Entities \| Subsidiaries \| MITY FSC, Inc.
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Ownership interest	100.00%		100.00%	100.00%
Reportable Legal Entities \| Subsidiaries \| Borda Canada \| MITY, Inc.
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Interest Income	$ 129	$ 0