v2.4.0.8

Employee Incentive Plans (2007 Stock Incentive Plan, ROI Summary) (Details) (2007 Stock Incentive Plan (Shares)) | 6 Months Ended
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Jun. 30, 2014
2007 Stock Incentive Plan (Shares) |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Beginning Balance | 11,647,117 |
Shares Granted |  |
Shares Forfeited | (143,185) |
Shares Distributed | (2,434,794) | [1]
Ending Balance | 9,069,138 |
[1] | Shares cumulatively distributed under the 2007 Stock Incentive Plan include 16,238 shares from Treasury representing shares acquired at the IPO to satisfy obligations under the 2007 ROI Unit Stock Plan.

X
- Definition Shares granted, net of shares distributed and forfeited. + References No definition available. + Details
Name: | ibkr_NetShares
Namespace Prefix: | ibkr_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Total shares distributed during the period. + References No definition available. + Details
Name: | ibkr_SharesDistributed
Namespace Prefix: | ibkr_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Shares forfeited during the period. + References No definition available. + Details
Name: | ibkr_SharesForfeited
Namespace Prefix: | ibkr_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Shares granted during the period. + References No definition available. + Details
Name: | ibkr_StockPlanCompensationSharesGranted
Namespace Prefix: | ibkr_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration