Segment and Geographic Information - Reconciliation of Reportable Segment Assets to Corresponding Consolidated Amounts (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting Information [Line Items]
Cash and cash equivalents, restricted cash, and marketable securities	$ 244,012	$ 260,678
Deferred tax asset	10,043	3,976
Assets held for sale	495,213	321,581
Assets	1,819,512	1,559,265
Operating Segments
Segment Reporting Information [Line Items]
Assets	1,059,007	956,701
Segment Reconciling Items
Segment Reporting Information [Line Items]
Other assets	$ 11,237	$ 16,329