Condensed Consolidated Statements of Cash Flows - USD ($)	9 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Cash flows from operating activities:
Net income	$ 13,106,000	$ 11,561,000
Adjustments to reconcile net income to cash provided by (used in) operating activities:
Purchase of marketable securities	(45,945,000)	(118,867,000)
Proceeds from sale and maturity of marketable securities	44,125,000	122,282,000
Change in value of marketable securities	(1,733,000)	(2,528,000)
Deferred and other income taxes	(106,000)	1,021,000
Depreciation and amortization	1,971,000	2,091,000
Provision for credit losses		290,000
Loss on disposal of assets		157,000
Changes in assets and liabilities:
Accounts receivable	(456,000)	(771,000)
Costs and estimated earnings in excess of billings	(1,192,000)	(4,795,000)
Inventories	8,295,000	(10,976,000)
Prepaid expenses and other current assets	1,638,000	(326,000)
Accounts payable	(923,000)	(851,000)
Customer deposits	(4,255,000)	(30,000)
Accrued expenses	(2,013,000)	93,000
Total adjustments	(594,000)	(13,210,000)
Cash flows provided by (used in) operating activities	12,512,000	(1,649,000)
Cash flows from investing activities:
Capital expenditures	(763,000)	(1,726,000)
Cash flows used in investing activities	(763,000)	(1,726,000)
Net increase (decrease) in cash and cash equivalents	11,749,000	(3,375,000)
Cash and cash equivalents at:
Beginning of period	17,031,000	9,581,000
End of period	28,780,000	6,206,000
Non-cash investing and financing activities:
Right-of-use assets obtained in exchange for operating lease liabilities	$ 361,000	$ 352,000