Name:	ibkr_OverFiftyNinePercentUnvestedSharesEligible
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Data Type:	dtr-types:percentItemType
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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
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Significant Accounting Policies [Line Items]

No definition available.

Name:	ibkr_SignificantAccountingPoliciesLineItems
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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:	dtr-types:percentItemType
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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
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Data Type:	dtr-types: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:	dtr-types: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
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
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Period Type:	instant

Remaining lease term of operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 7A
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478964/842-20-50-7A

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478964/842-20-50-3

Name:	us-gaap_LesseeOperatingLeaseRemainingLeaseTerm
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Data Type:	xbrli:durationItemType
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Period Type:	instant

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
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Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

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:
Data Type:	na
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