Income Taxes - Narrative (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Tax Credit Carryforward [Line Items]
Federal net operating loss carryforwards	$ 61,000
Federal and state net operating loss carryforwards	149,299	$ 177,611
State net operating loss carryforwards	33,900
Valuation allowance	(25,396)	(29,059)
Pre-tax income required to realize deferred tax assets prior to expiration	907,100
Unrecognized tax benefits	3,358	$ 3,358	$ 3,441	$ 3,473
Federal tax authority
Tax Credit Carryforward [Line Items]
Federal and state net operating loss carryforwards	$ 57,800