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Regulatory Requirements and Subsidiary Dividend Restrictions - Narrative (Details) | 12 Months Ended
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Sep. 30, 2020 USD ($)
Capital and Other Regulatory Requirements [Line Items] |
Adjusted net capital | $ 5,000,000.0
Net capital under commodity exchange act computation | 20,000,000.0
Required net capital under commodity exchange act | 10,000,000.0
StoneX Financial [Member] |
Capital and Other Regulatory Requirements [Line Items] |
Adjusted net capital | 1,000,000
Adjusted net capital of percentage | $ 0.08
Broker-dealer, minimum net capital required, dividend withdrawal threshold, percent | 120.00%
Gain Capital Group, LLC [Member] |
Capital and Other Regulatory Requirements [Line Items] |
Adjusted net capital | $ 1,000,000.0
Adjusted net capital of percentage | 0.08
Net capital under commodity exchange act computation | $ 71,500,000
Percentage of net capital under commodity exchange act computation | 5.00%
Required net capital under commodity exchange act | $ 32,200,000
Percentage of required net capital under commodity exchange act | 10.00%

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- Definition Broker-Dealer, Minimum Net Capital Required, Parent, Dividend Withdrawal Threshold, Percent + References No definition available. + Details
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- Definition Capital and Other Regulatory Requirements [Line Items] + References No definition available. + Details
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- Definition Futures Commission Merchant, Commodity Exchange Act, Adjusted Net Capital, Percent Of Retail Customer Liabilities Over Threshold + References No definition available. + Details
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- Definition Futures Commission Merchant, Commodity Exchange Act, Required Net Capital, Percent Of Liabilities Owed to Counterparties + References No definition available. + Details
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- Definition Minimum amount of net capital required to be maintained by broker-dealer subsidiary to engage in security transaction, calculated under Aggregate Indebtedness Standard. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher SEC -Name Rule 15c3-1 -Number 240 -Section 15c3-1 + Details
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- Definition Minimum amount of net capital required to be maintained by broker-dealer parent, calculated under Aggregate Indebtedness Standard. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher SEC -Name Rule 15c3-1 -Number 240 -Section 15c3-1 + Details
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- Definition Amount of adjusted net capital of futures commission merchant (FCM) per Commodity Futures Trading Commission's (CFTC) requirement. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher CFTC -Name Rule 17 -Number 1 -Section 17 -Paragraph (a) -Subparagraph (5) + Details
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- Definition Amount of net capital required to be maintained by futures commission merchant (FCM) per Commodity Futures Trading Commission's (CFTC) requirement. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher CFTC -Name Rule 17 -Number 1 -Section 17 -Paragraph (a) -Subparagraph (1)(i) + Details
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- Details
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