Condensed Consolidated Balance Sheets - USD ($)	Dec. 31, 2020	Sep. 30, 2020
Current assets:
Cash and cash equivalents	$ 23,957,000	$ 35,584,000
Marketable securities at fair value (cost of $90,158,000 at December 31, 2020 and $89,514,000 at September 30, 2020)	92,049,000	89,498,000
Accounts receivable, less allowance for doubtful accounts of $360,000 at December 31, 2020 and $442,000 at September 30, 2020	2,764,000	1,992,000
Costs and estimated earnings in excess of billings	4,709,000	6,405,000
Inventories, net	35,473,000	27,090,000
Prepaid expenses	1,114,000	1,189,000
Total current assets	160,066,000	161,758,000
Property and equipment, net	12,087,000	8,341,000
Other long-term assets	1,159,000	995,000
Total Assets	173,312,000	171,094,000
Current liabilities:
Accounts payable	3,224,000	1,728,000
Customer deposits	2,697,000	3,853,000
Accrued expenses	2,386,000	2,605,000
Current operating lease liabilities	420,000	328,000
Total current liabilities	8,727,000	8,514,000
Deferred and other income taxes	1,128,000	746,000
Non-current operating lease liabilities	686,000	614,000
Total liabilities	10,541,000	9,874,000
Commitments and contingencies
Shareholders' equity:
Preferred stock, par value $.10 per share; 300,000 shares authorized; none issued
Capital in excess of par value	12,331,000	12,331,000
Retained earnings	148,979,000	147,428,000
Total shareholders' equity	162,771,000	161,220,000
Total Liabilities and Shareholders' Equity	173,312,000	171,094,000
Common Stock [Member]
Shareholders' equity:
Common stock	1,229,000	1,229,000
Total shareholders' equity	1,229,000	1,229,000
Class B Stock [Member]
Shareholders' equity:
Common stock	232,000	232,000
Total shareholders' equity	$ 232,000	$ 232,000