Note 2 - Investments in Debt and Equity Securities (Details Textual) - USD ($)	3 Months Ended
	Dec. 31, 2018	Dec. 31, 2019	Sep. 30, 2019
Equity Securities, FV-NI		$ 8,234,000	$ 8,136,000
Debt Securities, Available-for-sale, Total		$ 60,587,000	$ 56,123,000	[1]
US Treasury Securities [Member]
Debt Securities, Available-for-sale, Total	$ 35,800,000
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, after Tax, Total	135,000
Other Comprehensive Income (Loss), Securities, Available-for-sale, Tax, Total	$ 52,000

[1] At September 30, 2018, the Company reported investments in equity securities and available for sale debt securities as a single line item on the Company's condensed consolidated balance sheet. With the Company's adoption of ASU No. 2016-01 on October 1, 2018, the Company has included the current breakout above for comparability purposes only.