XML 84 R62.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Assets and Liabilities, at Fair Value - Details of Level 3 Assets and Liabilities (Details) - USD ($) $ in Millions | Sep. 30, 2017 | Sep. 30, 2016 | Sep. 30, 2015
--- | --- | --- | ---
Assets and Liabilities, at Fair Value [Abstract] |  |  |
Total Level 3 Assets | $ 0.1 | $ 3.2 |
Level 3 assets for which the company bears economic exposure | 0.1 | 3.2 |
Assets | 6,243.4 | $ 5,950.3 | $ 5,070.0
Assets, Fair Value Disclosure | $ 2,068.0 |  |
Total level 3 assets as a percentage of total assets | 0.00% | 0.10% |
Level 3 assets for which the company bears economic exposure as a percertange of total assets | 0.00% | 0.10% |
Total level 3 assets as a percentage of total financial assets at fair value | 0.00% | 0.10% |

X
- Definition Assets and Liabilities, at Fair Value [Abstract] + References No definition available. + Details
Name: | intl_AssetsAndLiabilitiesAtFairValueAbstract
Namespace Prefix: | intl_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Level 3 assets for which the company bears economic exposure + References No definition available. + Details
Name: | intl_Level3AssetsForWhichCompanyBearsEconomicExposure
Namespace Prefix: | intl_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Level 3 assets for which the company bears economic exposure as a percertange of total assets + References No definition available. + Details
Name: | intl_Level3AssetsForWhichCompanyBearsEconomicExposureAsPercertangeOfTotalAssets
Namespace Prefix: | intl_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Total Level 3 Assets + References No definition available. + Details
Name: | intl_TotalLevel3Assets
Namespace Prefix: | intl_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Total level 3 assets as a percentage of total assets + References No definition available. + Details
Name: | intl_TotalLevel3AssetsAsPercentageOfTotalAssets
Namespace Prefix: | intl_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Total level 3 assets as a percentage of total financial assets at fair value + References No definition available. + Details
Name: | intl_TotalLevel3AssetsAsPercentageOfTotalFinancialAssetsAtFairValue
Namespace Prefix: | intl_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(12)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(11)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
Name: | us-gaap_Assets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258 + Details
Name: | us-gaap_AssetsFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant