Note 2 - Summary of Significant Accounting Policies - Revenue From Asset Management Operations (Details) - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Management Fee Revenue [Member] | Willow Oak Asset Management LLC [Member]
Asset management operations revenue	$ 15,167
Asset Management [Member] | Willow Oak Asset Management LLC [Member]
Asset management operations revenue	24,513
Asset Management [Member] | Crossing Bridge Advisor LLC [Member]
Asset management operations revenue	1,727,254	$ 1,707,124
Asset Management [Member] | Crossing Bridge Advisor LLC [Member] | CrossingBridge Family of Funds [Member]
Asset management operations revenue	1,025,464	999,258
Asset Management [Member] | Crossing Bridge Advisor LLC [Member] | Two 1940 Act Regulated Mutual Funds [Member]
Asset management operations revenue	547,926	707,866
Fund Management Services Revenue [Member] | Willow Oak Asset Management LLC [Member]
Asset management operations revenue	9,346
Fund Management Services Revenue [Member] | Crossing Bridge Advisor LLC [Member]
Asset management operations revenue	153,864	$ 0
Performance Fee Revenue [Member] | Willow Oak Asset Management LLC [Member]
Asset management operations revenue	$ 0