Note 9 - Income Taxes (Details Textual) - USD ($)	3 Months Ended		6 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022
Income Tax Expense (Benefit)	$ 3,835,000	$ (10,630,000)	$ 9,935,000	$ (6,070,000)
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	$ 13,268,000	$ (38,443,000)	37,195,000	(27,005,000)
Effective Income Tax Rate Reconciliation, Realized Gains on Marketable Securities, Amount			110,000	3,841,000
Effective Income Tax Rate Reconciliation, Unrealized Gains (Losses) on Marketable Securities, Amount			8,770,000	11,971,000
Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount			1,005,000	(740,000)
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount			210,000	1,445,000
Effective Income Tax Rate Reconciliation, Deduction, Dividends, Amount			$ 160,000	$ 125,000
Effective Income Tax Rate Reconciliation, Percent			0.00%	22.50%
Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount			$ (1,005,000)	$ 740,000
Domestic Tax Authority [Member]
Open Tax Year			2020 2021 2022
State and Local Jurisdiction [Member]
Open Tax Year			2019 2020 2021 2022