Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Name:	us-gaap_GoodwillImpairmentLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Goodwill - Additional Information (Details) - USD ($)	12 Months Ended
Goodwill - Additional Information (Details) - USD ($)	Sep. 30, 2020	Sep. 30, 2018
Semiconductor
Goodwill [Line Items]
Impairment of goodwill	$ 0
SiC/LED
Goodwill [Line Items]
Impairment of goodwill	$ 0
Solar
Goodwill [Line Items]
Impairment of goodwill		$ 5,700,000