Note 1 - Organization and Significant Accounting Policies (Details Textual)			3 Months Ended		8 Months Ended	12 Months Ended
	Mar. 16, 2023 USD ($)	Sep. 08, 2022 USD ($)	Mar. 31, 2023 USD ($)	Mar. 31, 2022 USD ($)	Mar. 31, 2023 USD ($)	Dec. 31, 2022 USD ($) shares	Sep. 30, 2022 USD ($)
Number of Reportable Segments					4
Investment Owned, Cost			$ 1,405,266		$ 1,405,266	$ 450,000
Financing Receivable, after Allowance for Credit Loss, Current			384,400		384,400	50,000
Payments to Acquire Investments, Total			547,667	$ (2,849)
Crossing Bridge Advisor LLC [Member]
Investments, Fair Value Disclosure			511,672		511,672
Triad Guaranty, Inc. [Member]
Financing Receivable, after Allowance for Credit Loss, Noncurrent						$ 50,000
Investment Owned, Balance, Shares (in shares) | shares						847,847
Equity Securities without Readily Determinable Fair Value, Amount						$ 0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Period Increase (Decrease)			(334,000)
Mutual Fund [Member] | Crossing Bridge Advisor LLC [Member]
Payments to Acquire Investments, Total						$ 4,500,000
Minimum [Member] | Triad Guaranty, Inc. [Member]
Percentage of Annual Interest Rate on Promissory Note						12.00%
Maximum [Member] | Triad Guaranty, Inc. [Member]
Percentage of Annual Interest Rate on Promissory Note						18.00%
Crossing Bridge Advisor LLC [Member] | Minimum [Member]
Assets under Management, Carrying Amount			1,300,000,000		1,300,000,000
eBuild Ventures, LLC [Member] | Start-up Phase Private Company [Member]
Payments to Acquire Equity Securities, FV-NI		$ 450,000
Investment Ownership Percentage		10.00%
Investment Owned, Cost							$ 450,000
eBuild Ventures, LLC [Member] | Private E-Commerce Company Fulfilled by Amazon [Member]
Payments to Acquire Equity Securities, FV-NI	$ 955,266
Investment Ownership Percentage	3.00%
Investment Owned, Cost			$ 955,266		$ 955,266