Revenue - Summary of Accounts Receivable Billed and Unbilled and Deferred Revenue (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022
Revenue from Contract with Customer [Abstract]
Accounts receivable - billed (net of allowances for doubtful accounts of $19,801 and $16,627 as of September 30, 2023 and 2022, respectively)	$ 732,979	$ 789,611
Accounts receivable — unbilled (current)	211,498	157,166
Accounts receivable — unbilled (non-current)	45,176	27,417
Total Accounts receivable — unbilled	256,674	184,583
Deferred revenue (current)	(170,634)	(253,686)
Deferred revenue (non-current)	(805)	(69,907)
Total Deferred revenue	$ (171,439)	$ (323,593)

Unbilled receivables noncurrent.

No definition available.

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- Definition

Amounts due for billed services rendered or to be rendered, actions taken or to be taken, or a promise to refrain from taking certain actions in accordance with the terms of a legally binding agreement between the Company and, at a minimum, one other party. An example would be amounts billed to customers under contracts or programs but not paid as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 912
-SubTopic 310
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482312/912-310-45-2

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of deferred income and obligation to transfer product and service to customer for which consideration has been received or is receivable.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(26)(c))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of deferred income and obligation to transfer product and service to customer for which consideration has been received or is receivable, classified as current.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(20))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

+ Details

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- Definition

Amount of deferred income and obligation to transfer product and service to customer for which consideration has been received or is receivable, classified as noncurrent.

+ References

+ Details

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Namespace Prefix:	us-gaap_
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Balance Type:	credit
Period Type:	instant

- References

No definition available.

+ Details

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- Definition

Unbilled amounts due for services rendered or to be rendered, actions taken or to be taken, or a promise to refrain from taking certain actions in accordance with the terms of a legally binding agreement between the entity and, at a minimum, one other party. An example would be amounts associated with contracts or programs where the recognized revenue for performance thereunder exceeds the amounts billed under the terms thereof as of the date of the balance sheet.

+ References

+ Details

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Balance Type:	debit
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- Definition

Amount received for services rendered and products shipped, but not yet billed, for non-contractual agreements due within one year or the normal operating cycle, if longer.

+ References

No definition available.

+ Details

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Period Type:	instant