Name:	ibkr_OverFiftyNinePercentUnvestedSharesEligible
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Data Type:	num:percentItemType
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Period Type:	instant

Percentage of unvested shares forfeited by employees who discontinue employment with the Company without cause and continue to meet the terms of the plans' post-employment provisions.

No definition available.

Name:	ibkr_PercentSharesForfeitedPostEmployment
Namespace Prefix:	ibkr_
Data Type:	num:percentItemType
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Significant Accounting Policies [Line Items]

No definition available.

Name:	ibkr_SignificantAccountingPoliciesLineItems
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Data Type:	xbrli:stringItemType
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Percent of fair value of stock grant expensed during the first year of the grant for employees who are over fifty nine years old.

No definition available.

Name:	ibkr_StockGrantedExpenseOverFiftyNine
Namespace Prefix:	ibkr_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

Percent of fair value of stock grant expensed over the related vesting period utilizing the “graded vesting” method permitted under ASC Topic 718.

No definition available.

Name:	ibkr_StockGrantedExpenseRemainingVestingPeriod
Namespace Prefix:	ibkr_
Data Type:	num:percentItemType
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Period Type:	instant

Percent of fair value of stock grant expensed in the year of the grant.

No definition available.

Name:	ibkr_StockGrantedExpenseYearOfGrant
Namespace Prefix:	ibkr_
Data Type:	num:percentItemType
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Period Type:	instant

Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

Name:	us-gaap_FiniteLivedIntangibleAssetUsefulLife
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Data Type:	xbrli:durationItemType
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Describes the periods of time over which an entity anticipates to receive utility from its property, plant and equipment (that is, the periods of time over which an entity allocates the initial cost of its property, plant and equipment).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 35
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=68071081&loc=d3e1205-110223

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=84158767&loc=d3e18780-107790

Name:	us-gaap_PropertyPlantAndEquipmentEstimatedUsefulLives
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Data Type:	xbrli:stringItemType
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Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

No definition available.

Name:	us-gaap_PropertyPlantAndEquipmentUsefulLife
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_ComputerEquipmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=ibkr_OfficeFurnitureAndEquipmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_SoftwareAndSoftwareDevelopmentCostsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_FiniteLivedIntangibleAssetsMember
Namespace Prefix:
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