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Regulatory Requirements and Subsidiary Dividend Restrictions - Minimum Regulatory Net Capital (Details) $ in Millions | Sep. 30, 2020 USD ($)
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Capital and Other Regulatory Requirements [Line Items] |
Actual | $ 20.0
Minimum Requirement | 10.0
StoneX Financial Inc. [Member] |
Capital and Other Regulatory Requirements [Line Items] |
Actual | 229.8
Minimum Requirement | 137.6
StoneX Financial Ltd. [Member] |
Capital and Other Regulatory Requirements [Line Items] |
Actual | 264.3
Minimum Requirement | 145.1
Gain Capital Group, LLC [Member] |
Capital and Other Regulatory Requirements [Line Items] |
Actual | 71.5
Minimum Requirement | 32.2
Gain Capital U.K. Ltd [Member] |
Capital and Other Regulatory Requirements [Line Items] |
Actual | 185.4
Minimum Requirement | $ 65.2

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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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