Income Taxes - Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Unrecognized Tax Benefits [Roll Forward]
Gross unrecognized tax benefits at beginning of year	$ 19,879	$ 13,849	$ 12,980
Gross increases for tax positions in prior years	678	4,769	0
Gross decreases for tax positions in prior years	0	(1,956)	(1,127)
Gross increases based on tax positions related to the current year	3,675	4,277	3,650
Decreases for settlements and payments	0	0	(523)
Decreases due to statute expiration	(4,727)	(1,060)	(1,131)
Gross unrecognized tax benefits at end of year	$ 19,505	$ 19,879	$ 13,849

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

No definition available.

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- Definition

Amount of unrecognized tax benefits.

+ References

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Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

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Amount of decrease in unrecognized tax benefits resulting from settlements with taxing authorities.

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Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return.

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Amount of increase in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

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Amount of decrease in unrecognized tax benefits resulting from lapses of applicable statutes of limitations.

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