Note 8 - Investments in Marketable Securities (Tables)

6 Months Ended

Mar. 31, 2023

Notes Tables

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

	March 31, 2023						September 30, 2022
	Aggregate fair value		Amortized/ Adjusted cost basis		Pretax unrealized gains		Aggregate fair value		Amortized/ Adjusted cost basis		Pretax unrealized gains
Marketable securities
Common stocks	$	318,773,000	$	165,412,000	$	153,361,000	$	275,529,000	$	154,837,000	$	120,692,000