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Note 2 - Summary of Significant Accounting Policies (Tables)

12 Months Ended

Sep. 30, 2021

Notes Tables

Schedule of Available-for-sale Securities Reconciliation [Table Text Block]

		September 30, 2021												September 30, 2020
		Aggregate fair value				Amortized/ Adjusted cost basis				Pretax unrealized gains				Aggregate fair value				Amortized/ Adjusted cost basis				Pretax unrealized gains
Marketable securities
Common stocks		$	347,573,000			$	103,480,000			$	244,093,000			$	179,368,000			$	41,775,000			$	137,593,000

Valuation and Qualifying Accounts [Table Text Block]

Description		Balance at Beginning of Year				Additions (Reductions) Charged to Costs and Expenses				Accounts Charged off less Recoveries				Balance at End of Year
Fiscal 2021
Allowance for doubtful accounts		$	250,000			$	(3,000	)		$	3,000			$	250,000
Fiscal 2020
Allowance for doubtful accounts		$	200,000			$	116,000			$	(66,000	)		$	250,000

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