Contract Balance - Receivables (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Sep. 30, 2022
Revenue from Contract with Customer [Abstract]
Billed	$ 235,564	$ 203,351
Unbilled	201,296	165,386
Receivables Gross	436,860	368,737
Less: allowance for doubtful accounts	(4,941)	(4,218)
Accounts Receivable, after Allowance for Credit Loss	431,919	364,519
Less: long-term receivables	(47,895)	(42,109)
Accounts receivable, net	$ 384,024	$ 322,410

Receivables, Gross

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Amount, before allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business.

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Amount, after allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business.

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Amount, after allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business, classified as current.

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Amount, after allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business, classified as noncurrent.

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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.

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