Represents the amortization period of repayment following the revolving period for home equity loans.

No definition available.

Name:	bokf_AmortizationPeriodFollowingRevolvingPeriodforHomeEquityLoans
Namespace Prefix:	bokf_
Data Type:	us-types:durationStringItemType
Balance Type:	na
Period Type:	duration

- Definition

-- None. No documentation exists for this element. --

+ References

No definition available.

+ Details

Name:	bokf_CreditCommitmentsAbstract
Namespace Prefix:	bokf_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Describes the general components and status of home equity loans serviced by the entity outstanding as of the Balance Sheet date.

+ References

No definition available.

+ Details

Name:	bokf_HomeEquityLoansDescription
Namespace Prefix:	bokf_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Represent additional revolving period that may be extended at the discretion of management.

+ References

No definition available.

+ Details

Name:	bokf_HomeEquityLoansDiscretionaryAdditionalRevolvingPeriod
Namespace Prefix:	bokf_
Data Type:	us-types:durationStringItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum dollar amount of loans in this category with individual loan amount less than specified threshold.

+ References

No definition available.

+ Details

Name:	bokf_MaximumAmountOfLoansWithBalancesBelowThreshold
Namespace Prefix:	bokf_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents the maximum debt-to-income (DTI) ratio on loans approved.

+ References

No definition available.

+ Details

Name:	bokf_MaximumDebtToIncomeRatioOnLoans
Namespace Prefix:	bokf_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Maximum loan amount for specified individual loans in category.

+ References

No definition available.

+ Details

Name:	bokf_MaximumLoanAmountForCertainIndividualLoansInCategory
Namespace Prefix:	bokf_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents the maximum loan-to-value (LTV) ratio on loans approved.

+ References

No definition available.

+ Details

Name:	bokf_MaximumLoanToValueRatioOnLoans
Namespace Prefix:	bokf_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Represent the maximum number of years that a variable rate jumbo residential mortgage loan will have a fixed rate of interest.

+ References

No definition available.

+ Details

Name:	bokf_MaximumPeriodforFixedRateonVariableRateJumboResidentialMortgageLoan
Namespace Prefix:	bokf_
Data Type:	us-types:durationStringItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the minimum FICO score required for loan approval.

+ References

No definition available.

+ Details

Name:	bokf_MinimumFicoRequiredForLoanApproval
Namespace Prefix:	bokf_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the minimum loan-to-value (LTV) ratio acceptable for loans to be approved.

+ References

No definition available.

+ Details

Name:	bokf_MinimumLoanToValueRatioOnLoans
Namespace Prefix:	bokf_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The minimum number o years that a variable rate jumbo residential mortgage loan will have a fixed rate of interest.

+ References

No definition available.

+ Details

Name:	bokf_MinimumPeriodForFixedRateOnVariableRateJumboResidentialMortgageLoans
Namespace Prefix:	bokf_
Data Type:	us-types:durationStringItemType
Balance Type:	na
Period Type:	duration

- Definition

An irrevocable guarantee to extend credit to a party based on current credit policies.

+ References

No definition available.

+ Details

Name:	bokf_OutstandingStandbyLettersOfCredit
Namespace Prefix:	bokf_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Percentage of committed energy production loans secured by properties producing natural gas

+ References

No definition available.

+ Details

Name:	bokf_PercentageOfCommittedEnergyProductionLoansSecuredByNaturalGas
Namespace Prefix:	bokf_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of committed energy production loans secured by properties primarily producing oil

+ References

No definition available.

+ Details

Name:	bokf_PercentageOfCommittedEnergyProductionLoansSecuredByOil
Namespace Prefix:	bokf_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of home equity portfolio comprised of first lien loans

+ References

No definition available.

+ Details

Name:	bokf_PercentageOfHomeEquityPortfolioComprisedOfFirstLienLoans
Namespace Prefix:	bokf_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of home equity portfolio comprised of junior lien loans

+ References

No definition available.

+ Details

Name:	bokf_PercentageOfHomeEquityPortfolioComprisedOfJuniorLienLoans
Namespace Prefix:	bokf_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of junior lien home equity loans that are amortizing term loans

+ References

No definition available.

+ Details

Name:	bokf_PercentageOfJuniorLienHomeEquityLoansThatAreAmortizingTermLoans
Namespace Prefix:	bokf_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of junior lien home equity loans that are revolving lines of credit

+ References

No definition available.

+ Details

Name:	bokf_PercentageOfJuniorLienHomeEquityLoansThatAreRevolvingLinesOfCredit
Namespace Prefix:	bokf_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Reflects the percentage of the loan in portfolio secured by property in the state of Oklahoma.

+ References

No definition available.

+ Details

Name:	bokf_PercentageOfLoanPortfolioSecuredByPropertyInOklahoma
Namespace Prefix:	bokf_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Reflects the percentage of the loan in portfolio secured by property in the state of Texas.

+ References

No definition available.

+ Details

Name:	bokf_PercentageOfLoanPortfolioSecuredByPropertyInTexas
Namespace Prefix:	bokf_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage Of Loan Portfolio Secured By Property in Colorado

+ References

No definition available.

+ Details

Name:	bokf_PercentageOfLoanPortfolioSecuredByPropertyinColorado
Namespace Prefix:	bokf_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents percentage of given loan class to total loans.

+ References

No definition available.

+ Details

Name:	bokf_PercentageofLoanClasstoTotalLoans
Namespace Prefix:	bokf_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the revolving period for home equity loans.

+ References

No definition available.

+ Details

Name:	bokf_RevolvingPeriodforHomeEquityLoans
Namespace Prefix:	bokf_
Data Type:	us-types:durationStringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of financing receivable 90 days or more past due and still accruing.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 16
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=119407570&loc=SL82919258-210447

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5111-111524

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 55
-Paragraph 80
-URI http://asc.fasb.org/extlink&oid=118955255&loc=SL82922355-210448

+ Details

Name:	us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- References

No definition available.

+ Details

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

- Definition

Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=118952595&loc=d3e4428-111522

+ Details

Name:	us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Reflects the amount of additional interest income that would have been recorded if impaired or nonperforming loans were instead current, in compliance with their original terms, and outstanding throughout the reporting period or since origination (if held for part of the period).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 40
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=118939409&loc=d3e18794-111554

+ Details

Name:	us-gaap_LoansAndLeasesReceivableImpairedInterestLostOnNonaccrualLoans
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Reflects the carrying amount of loans deemed to be questionable as to collection on which no interest is continuing to be recognized.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5111-111524

+ Details

Name:	us-gaap_LoansAndLeasesReceivableImpairedNonperformingNonaccrualOfInterest
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

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

- Definition

Amount of loan with fixed rate of interest.

+ References

+ Details

Name:	us-gaap_LoansReceivableWithFixedRatesOfInterest1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of loan with variable or adjustable rate of interest.

+ References

+ Details

Name:	us-gaap_LoansReceivableWithVariableRatesOfInterest1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Unused amount of commitments to extend credit to customers.

+ References

No definition available.

+ Details

Name:	us-gaap_UnusedCommitmentsToExtendCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_ConcentrationRiskByTypeAxis=us-gaap_GeographicConcentrationRiskMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementGeographicalAxis=stpr_TX
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementGeographicalAxis=stpr_OK
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementGeographicalAxis=stpr_CO
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=bokf_ServicesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConcentrationRiskByTypeAxis=us-gaap_CreditConcentrationRiskMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=bokf_EnergyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=bokf_EnergyProducersMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_HealthCareMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialRealEstatePortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ResidentialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=bokf_PermanentResidentialMortgageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=bokf_PermanentMortgagesGuaranteedByUsGovernmentAgenciesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_HomeEquityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: