Condensed Consolidated Balance Sheets (Parenthetical) - USD ($)	Dec. 31, 2025	Sep. 30, 2025
Marketable securities, cost	$ 108,356,000	$ 107,237,000
Accounts receivable, allowance for doubtful accounts	$ 498,000	$ 434,000
Preferred stock, par value	$ 0.10	$ 0.10
Preferred stock, shares authorized	300,000	300,000
Preferred stock, shares issued	0	0
Common Stock [Member]
Common stock, par value	$ 0.10	$ 0.10
Common stock, shares authorized	15,000,000	15,000,000
Common stock, shares issued	12,338,845	12,338,845
Common stock, shares outstanding	12,338,845	12,338,845
Class B common stock [Member]
Common stock, par value	$ 10	$ 10
Common stock, shares authorized	6,000,000	6,000,000
Common stock, shares issued	2,318,857	2,318,857
Common stock, shares outstanding	2,318,857	2,318,857