Income Taxes - Reconciliation of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of period	$ 1,377	$ 1,409	$ 1,252
Increases related to tax positions taken during the current period	400	240	251
Increases related to tax positions taken during a prior period	112	92	75
Decreases related to expiration of statute of limitations	0	(327)	0
Decreases related to settlement with taxing authorities	0	(37)	(169)
Balance at end of period	$ 1,889	$ 1,377	$ 1,409