Fair Value of shares granted under the 2007 Stock Incentive Plan.

No definition available.

Name:	ibkr_FairValueShareBasedCompensationSIPSharesGranted
Namespace Prefix:	ibkr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Fair Value of all shares granted under the 2007 Stock Incentive Plan from the IPO to date.

No definition available.

Name:	ibkr_FairValueShareBasedCompensationSIPSharesGrantedIPOToDate
Namespace Prefix:	ibkr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Number of shares granted under the 2007 Stock Incentive Plan.

No definition available.

Name:	ibkr_ShareBasedCompensationSharesGranted
Namespace Prefix:	ibkr_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

Shares granted under the Stock Incentive Plan from the IPO to date.

No definition available.

Name:	ibkr_ShareBasedCompensationSharesGrantedIPOToDate
Namespace Prefix:	ibkr_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

Stock Incentive Plan Granted Shares Adjustment for prior year end

No definition available.

Name:	ibkr_StockIncentivePlanGrantedSharesAdjustment
Namespace Prefix:	ibkr_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

No definition available.

Name:	us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration