Income Taxes - Aggregate Changes in Balance of Gross Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Balance at the beginning of the year	$ 87,144	$ 67,358
Beginning balance adjustment	(13,181)	9,884
Increases related to tax positions taken from prior periods	2,277	9,367
Increases related to tax positions taken during current period	2,088	768
Decreases for tax settlements and lapse in statutes	(1,738)	(233)
Balance at the end of the year	$ 76,590	$ 87,144