Note 9 - Income Taxes (Details Textual) - USD ($)	3 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Income Tax Expense (Benefit), Total	$ 6,100,000	$ 4,560,000
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest, Total	23,927,000	11,438,000
Effective Income Tax Rate Reconciliation, Realized Gains on Marketable Securities, Amount	110,000	1,556,000
Effective Income Tax Rate Reconciliation, Unrealized Gains (Losses) on Marketable Securities, Amount	6,360,000	$ 12,612,000
Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount	140,000
Effective Income Tax Rate Reconciliation, Deduction, Dividends, Amount	80,000
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount	$ 150,000
Effective Income Tax Rate Reconciliation, Percent, Total	0.00%	39.87%
Effective Income Tax Rate Reconciliation, Tax Contingency, State and Local, Amount		$ 9,747,000
Domestic Tax Authority [Member]
Open Tax Year	2020 2021 2022
State and Local Jurisdiction [Member]
Open Tax Year	2019 2020 2021 2022