Amount of the cumulative effect on retained earnings net of related income tax effect.

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Amount by which inventory stated at last-in first-out (LIFO) is less than (in excess of) inventory stated at other inventory cost methods.

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-SubTopic 10
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Inventories - Additional Information (Detail) - USD ($)	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Inventory [Line Items]
Slow moving and obsolete inventory reserve	$ 4,700,000	$ 4,543,000	$ 4,575,000
Inventory Valuation Adjustment [Member]
Inventory [Line Items]
Cumulative impact of change in accounting method inventory	$ 2,708,000