Commitments and Contingencies	6 Months Ended
Commitments and Contingencies	Mar. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Contingencies The Company had receivables, net of collections and other allowable deductions, of $11.1 million as of March 31, 2024, due from account holders in connection with the OptionSellers matter previously disclosed in the Company’s Annual Report on Form 10-K for the fiscal year ended September 30, 2023. The allowance against these uncollected balances was $3.5 million as of March 31, 2024. The Company is pursuing collection of the outstanding balances through arbitration proceedings against the account holders. The Company will consider developments in these proceedings, and any other relevant matters, in determining whether any changes in the allowance against the uncollected balances are required. In these and other arbitration proceedings, clients are seeking damages from StoneX Financial Inc. related to the trading losses in their accounts. During the six months ended March 31, 2024, the Company favorably resolved several of these arbitration claims through arbitration decisions and privately negotiated settlements. All of the arbitration panels that issued decisions during the period awarded StoneX Financial Inc. the full amount of the uncollected balances. As noted, several of the arbitrations were resolved through privately negotiated settlement, pursuant to which the account holders agreed to pay some or all of their outstanding deficit balances. The Company intends to continue vigorously pursuing claims through arbitration and settling cases in what the Company determines to be appropriate circumstances. The ultimate outcome of remaining arbitrations cannot presently be determined. Depending on future collections and the outcomes of arbitration proceedings, any provisions for bad debts and actual losses may be material to the Company’s financial results. However, the Company believes that the likelihood of a material adverse outcome is remote, and does not currently believe that any potential losses related to this matter would impact its ability to comply with its ongoing liquidity, capital, and regulatory requirements. Legal Proceedings From time to time and in the ordinary course of business, the Company is involved in various legal actions and proceedings, including tort claims, contractual disputes, employment matters, workers’ compensation claims and collections. The Company carries insurance that provides protection against certain types of claims, up to the relevant policy’s limits. On November 13, 2023, BTIG filed a civil complaint (the “BTIG complaint”) against the Company and StoneX Financial Inc. in San Francisco Superior Court (CGC-23-610525) seeking monetary damages and injunctive relief for, among other things, alleged theft of purported trade secrets by former BTIG employees later employed at StoneX. The Company intends to vigorously defend itself. In addition, the Company subsequently received from the U.S. Department of Justice (the “DOJ”) and the SEC subpoenas that the Company believes are related to conduct alleged in the BTIG complaint, and the Company is cooperating with these agencies. The ultimate outcomes of the BTIG complaint and the DOJ and SEC subpoenas cannot presently be determined. As of March 31, 2024 and September 30, 2023, the Condensed Consolidated Balance Sheets include loss contingency accruals which are not material, individually or in the aggregate, to the Company’s financial position or liquidity. In the opinion of management, possible exposure from loss contingencies in excess of the amounts accrued, is not likely to be material to the Company’s earnings, financial position or liquidity. Contractual Commitments Self-Insurance The Company self-insures its costs related to medical and dental claims. The Company is self-insured, up to a stop loss amount, for eligible participating employees and retirees, and for qualified dependent medical and dental claims, subject to deductibles and limitations. As of March 31, 2024, the Company had $1.7 million accrued for self-insured medical and dental claims included in Accounts payable and other accrued liabilities in the Condensed Consolidated Balance Sheet.