Stock-Based Compensation - Additional Information (Details) $ in Thousands	12 Months Ended
	Sep. 30, 2023 USD ($) shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	40,000
2003 Plan | Class A common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized (in shares)	19,700,000
Shares reserved for outstanding equity awards (in shares)	0
Shares reserved for future awards (in shares)	9,600,000
2003 Plan | Common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized (in shares)	5,800,000
Shares reserved for outstanding equity awards (in shares)	3,500,000
Shares reserved for future awards (in shares)	4,600,000
2003 Plan | Preferred Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized (in shares)	500,000,000
Shares reserved for outstanding equity awards (in shares)	3,500,000
Shares reserved for future awards (in shares)	500,000
Director Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	0
Director Plan | Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted shares maximum value | $	$ 120