Stock-Based Employee Benefit Plans - Summary of ESPP activities (Details) - $ / shares	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
ESPP, Discount from Market Price, Purchase Date	15.00%
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
ESPP, Discount from Market Price, Purchase Date	85.00%
ESPP, Shares Issued in Period	13,721	21,876	32,528
ESPP, Per Share Weighted Average Price of Shares Purchased	$ 1,217.05	$ 646.37	$ 393.95