Note 8 - Income Taxes (Details Textual) - USD ($)	3 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Tax Expense (Benefit), Total	$ 4,560,000	$ 22,180,000
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest, Total	11,438,000	81,450,000
Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount	230,000	63,000
Effective Income Tax Rate Reconciliation, Deduction, Dividends, Amount	91,000	84,000
Effective Income Tax Rate Reconciliation, Unrealized Gains (Losses) on Marketable Securities, Amount	(9,747,000)	22,360,000
Effective Income Tax Rate Reconciliation, Realized Gains on Marketable Securities, Amount	12,612,000
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount	$ 1,556,000	$ 159,000
Effective Income Tax Rate Reconciliation, Percent, Total	40.00%	27.00%
Domestic Tax Authority [Member]
Open Tax Year	2018
State and Local Jurisdiction [Member]
Open Tax Year	2017