Income Taxes (Unrecognized Tax Benefits, Additional Information) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Income Tax Contingency [Line Items]
Unrecognized tax benefits that would impact effective tax rate	$ 3,300
Unrecognized tax benefits	3,316	$ 2,908	$ 2,600	$ 1,713
Unrecognized Tax Benefits, Interest on Income Taxes Expense	100	100
Unrecognized Tax Benefits, Income Tax Penalties Accrued	0	$ 0
Noncurrent income taxes payable
Income Tax Contingency [Line Items]
Unrecognized tax benefits	2,400
Noncurrent deferred tax assets
Income Tax Contingency [Line Items]
Unrecognized tax benefits	900
Maximum
Income Tax Contingency [Line Items]
Decrease in unrecognized tax benefits that is reasonably possible	$ 300