Condensed Consolidated Statements of Cash Flows - USD ($)	9 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash flows from operations:
Net income	$ 6,174,000	$ 6,156,000
Adjustments to reconcile net income to cash flows provided by operating activities:
Purchases of marketable securities	(101,040,000)	(112,668,000)
Proceeds from sale and maturity of marketable securities	99,638,000	110,805,000
Change in fair value of marketable securities	(4,445,000)	1,510,000
Deferred income taxes	457,000	(2,066,000)
Depreciation and amortization	1,931,000	1,244,000
Provision for doubtful accounts	125,000	50,000
Stock-based compensation		53,000
Changes in assets and liabilities:
Accounts receivable	(1,253,000)	(56,000)
Costs and estimated earnings in excess of billings	7,090,000	3,774,000
Inventories (excluding the effect of the Blaw-Knox acquisition)	(3,357,000)	804,000
Prepaid expenses and other current assets	(44,000)	(1,150,000)
Accounts payable	2,678,000	182,000
Customer deposits	(92,000)	733,000
Accrued expenses and other current liabilities	268,000	34,000
Total adjustments	1,956,000	3,249,000
Cash flows provided by operating activities	8,130,000	9,405,000
Cash flows used in investing activities:
Acquisition of Blaw-Knox assets	(13,777,000)
Capital expenditures	(2,449,000)	(1,246,000)
Cash flows used in investing activities	(16,226,000)	(1,246,000)
Cash flows from financing activities:
Proceeds from stock option exercises	56,000	103,000
Cash flows provided by financing activities	56,000	103,000
Net increase (decrease) in cash	(8,040,000)	8,262,000
Cash at:
Beginning of period	35,584,000	10,302,000
End of period	27,544,000	$ 18,564,000
Non-cash investing activities:
Operating lease right of use assets	254,000
Operating lease liabilities	$ 254,000