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, 2020	$ 161,220,000	$ 12,331,000	$ 147,428,000	$ 1,229,000	$ 232,000
Beginning balance, shares at Sep. 30, 2020				12,287,337	2,318,857
Net income (loss)	5,805,000		5,805,000
Stock options exercised	$ 264,000	259,000		$ 5,000	$ 0
Stock options exercised, shares	51,508			51,508	0
Ending balance at Sep. 30, 2021	$ 167,289,000	12,590,000	153,233,000	$ 1,234,000	$ 232,000
Ending 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