Segment and Geographic Information - Reconciliation of Reportable Segment Assets to Corresponding Consolidated Amounts (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Sep. 30, 2022
Segment Reporting Information [Line Items]
Cash and cash equivalents, restricted cash, and marketable securities	$ 1,451,703	$ 2,305,081
Deferred tax asset	490	1,169
Other assets	23	181,479
Assets	3,249,814	3,716,122
Operating Segments
Segment Reporting Information [Line Items]
Assets	$ 1,797,598	$ 1,228,393