Consolidated Statements of Shareholders' Equity - USD ($)	Total	Capital in Excess of Par Value [Member]	Retained Earnings [Member]	Common Stock [Member] Common Stock [Member]	Class B Stock [Member] Common Stock [Member]
Beginning balance at Sep. 30, 2021	$ 167,289,000	$ 12,590,000	$ 153,233,000	$ 1,234,000	$ 232,000
Beginning balance, shares at Sep. 30, 2021				12,338,845	2,318,857
Net income (loss)	(372,000)		(372,000)
Ending balance at Sep. 30, 2022	166,917,000	12,590,000	152,861,000	$ 1,234,000	$ 232,000
Ending balance, shares at Sep. 30, 2022				12,338,845	2,318,857
Net income (loss)	14,666,000		14,666,000
Ending balance at Sep. 30, 2023	$ 181,583,000	$ 12,590,000	$ 167,527,000	$ 1,234,000	$ 232,000
Ending balance, shares at Sep. 30, 2023				12,338,845	2,318,857