Note 8 - Investments in Marketable Securities (Tables)

3 Months Ended

Dec. 31, 2023

Notes Tables

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

	December 31, 2023						September 30, 2023
	Aggregate fair value		Amortized/ Adjusted cost basis		Pretax unrealized gains		Aggregate fair value		Amortized/ Adjusted cost basis		Pretax unrealized gains
Marketable securities
Common stocks	$	317,818,000	$	165,412,000	$	152,406,000	$	303,128,000	$	165,412,000	$	137,716,000