Income Taxes - Narrative (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Tax Credit Carryforward [Line Items]
Federal net operating loss carryforwards	$ 21,300
Federal and state net operating loss and tax credit carryforwards	126,547	$ 138,856
State net operating loss carryforwards	33,600
Valuation allowance	(27,578)	(30,438)
Pre-tax income required to realize deferred tax assets prior to expiration	654,800
Unrecognized tax benefits	2,420	$ 3,358	$ 3,358	$ 3,358
Uncertain tax positions that will reverse within next twelve months	400
Federal tax authority
Tax Credit Carryforward [Line Items]
Federal and state net operating loss and tax credit carryforwards	$ 74,100