Stockholders Equity - Treasury stock activity (Details) - shares	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Stockholder's Equity
Number of shares at beginning of year	375,032	195,638	58,909
Repurchases of common stock to satisfy employee payroll taxes	17,708	37,002	23,751
Repurchases of common stock from share repurchase plan		142,392	112,978
Number of shares at end of year	392,740	375,032	195,638