Transactions with Controlled Companies - NMMB, Inc. (Details) - USD ($) $ in Thousands		3 Months Ended		12 Months Ended
	Dec. 30, 2019	Sep. 30, 2022	Sep. 30, 2021	Jun. 30, 2022
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Interest Income		$ 174,318	$ 146,271
Dividend Income		2,901	1,267
Realized Loss		(23,177)	(601)
Interest Receivable		18,781		$ 12,925
Other Receivables		$ 1,309		$ 745
NMMB, Inc.
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Recapitalization equity securities converted	92.42%
Dividends received	$ 2,797
NMMB, Inc. | First Lien Term Loan
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Recapitalization	$ 15,100
NMMB Holdings, Inc. | NMMB, Inc.
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Ownership interest		90.42%		90.42%
NMMB, Inc. | Armed Forces Communications, Inc.
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Ownership interest		100.00%
Refuel Agency, Inc. | NMMB, Inc.
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Ownership interest		100.00%
Reportable Legal Entities | Subsidiaries | NMMB Holdings, Inc.
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Ownership interest		100.00%
Reportable Legal Entities | Subsidiaries | NMMB, Inc.
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Interest Income		$ 818	131
Dividend Income		1,093	0
Realized Loss		(1,093)	0
Repayment of Loan Receivable		0	38
Interest Receivable		10		$ 9
Other Receivables		5		$ 5
Reportable Legal Entities | Subsidiaries | NMMB, Inc. | Prospect Administration
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Managerial Assistance		$ 100	$ 100