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Nature of Operations and Summary of Significant Accounting Policies - Schedule of Changes in Allowance for Slow Moving and Obsolete Inventories (Detail) - USD ($) | 12 Months Ended
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Sep. 30, 2020 | Sep. 30, 2019
Inventory Disclosure [Abstract] |  |
Balance, beginning of year | $ 4,700,000 | $ 4,543,000
Charged to cost of sales | 401,000 | 304,000
Disposal of inventory, net of recoveries | (484,000) | (147,000)
Balance, end of year | $ 4,617,000 | $ 4,700,000

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- Definition Amount by which inventory stated at last-in first-out (LIFO) is less than (in excess of) inventory stated at other inventory cost methods. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.6(c)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
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- Definition Amount of loss from reductions in inventory due to subsequent measurement adjustments, including, but not limited to, physical deterioration, obsolescence, or changes in price levels. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 330 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=116847112&loc=d3e4542-108314 + Details
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