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IBG LLC Ownership of Member Interests (Table) (Details) | Sep. 30, 2016 shares
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IBG Inc [Member] |
Ownership Percentage | 16.60%
Membership Interests | 67,987,957
Holdings [Member] |
Ownership Percentage | 83.40%
Membership Interests | 341,444,304

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- Definition The amount of membership interests in IBG LLC + References No definition available. + Details
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Namespace Prefix: | ibkr_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

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- Definition The percent of ownership in IBG LLC membership interests + References No definition available. + Details
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Namespace Prefix: | ibkr_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

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- Details
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Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
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Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |