XML 52 R42.htm IDEA: XBRL DOCUMENT v3.10.0.1

Loans and Allowance for Credit Losses, Loans by Portfolio Type (Details) - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017
Loan receivables disclosure [Abstract]
Loans, fixed rate of interest		$ 4,508,969	$ 4,529,296	$ 4,532,914
Loans, variable rate of interest		13,687,498	12,436,254	12,448,284
Loans, non-accrual		152,992	187,874	225,636
Total		18,349,459	17,153,424	17,206,834
Accruing loans past due (90 days)	[1]	518	633	253
Credit Commitments [Abstract]
Outstanding commitments to extend credit		10,700,000
Outstanding standby letters of credit		672,000
Texas [Member] | Geographic Concentration Risk [Member]
Loan receivables disclosure [Abstract]
Total		$ 6,100,000
Loans receivable, other information [Abstract]
Percentage of loan portfolio attributed to Texas (in hundredths)		33.00%
Oklahoma [Member] | Geographic Concentration Risk [Member]
Loan receivables disclosure [Abstract]
Total		$ 3,600,000
Loans receivable, other information [Abstract]
Percentage of loan portfolio attributed to Oklahoma (in hundredths)		20.00%
Commercial [Member]
Loan receivables disclosure [Abstract]
Loans, fixed rate of interest		$ 2,150,138	2,217,432	2,225,470
Loans, variable rate of interest		9,316,473	8,379,240	8,393,564
Loans, non-accrual		109,490	137,303	176,900
Total		11,576,101	10,733,975	10,795,934
Commercial [Member] | Texas [Member] | Geographic Concentration Risk [Member]
Loan receivables disclosure [Abstract]
Total		$ 3,800,000
Loans receivable, other information [Abstract]
Percentage of loan portfolio attributed to Texas (in hundredths)		33.00%
Commercial [Member] | Oklahoma [Member] | Geographic Concentration Risk [Member]
Loan receivables disclosure [Abstract]
Total		$ 2,300,000
Loans receivable, other information [Abstract]
Percentage of loan portfolio attributed to Oklahoma (in hundredths)		20.00%
Commercial [Member] | Energy [Member]
Loan receivables disclosure [Abstract]
Total		$ 3,294,867	2,930,156	2,867,981
Commercial [Member] | Energy [Member] | Credit Concentration Risk [Member]
Loan receivables disclosure [Abstract]
Total		$ 3,300,000
Loans receivable, other information [Abstract]
Percentage of loan class to total loans		18.00%
Commercial [Member] | Energy Producers [Member] | Credit Concentration Risk [Member]
Loan receivables disclosure [Abstract]
Total		$ 2,700,000
Loans receivable, other information [Abstract]
Percentage of committed energy production loans secured by oil		57.00%
Percentage of committed energy production loans secured by natural gas		43.00%
Commercial [Member] | Services [Member]
Loan receivables disclosure [Abstract]
Total		$ 3,017,311	2,986,949	2,967,513
Commercial [Member] | Services [Member] | Credit Concentration Risk [Member]
Loan receivables disclosure [Abstract]
Total		$ 3,000,000
Loans receivable, other information [Abstract]
Percentage of loan class to total loans		16.00%
Amount of loans with individual balances less than $10 million		$ 1,500,000
Maximum loan amount for certain individual loans in category		10,000
Commercial [Member] | Healthcare [Member]
Loan receivables disclosure [Abstract]
Total		2,437,323	2,314,753	2,239,451
Commercial [Member] | Healthcare [Member] | Credit Concentration Risk [Member]
Loan receivables disclosure [Abstract]
Total		$ 2,400,000
Loans receivable, other information [Abstract]
Percentage of loan class to total loans		13.00%
Commercial real estate [Member]
Loan receivables disclosure [Abstract]
Loans, fixed rate of interest		$ 603,515	548,692	564,681
Loans, variable rate of interest		3,199,844	2,928,440	2,950,486
Loans, non-accrual		1,316	2,855	2,975
Total		$ 3,804,675	3,479,987	3,518,142
Commercial real estate [Member] | Texas [Member] | Geographic Concentration Risk [Member]
Loans receivable, other information [Abstract]
Percentage of loan portfolio secured by property in Texas (in hundredths)		32.00%
Commercial real estate [Member] | Oklahoma [Member] | Geographic Concentration Risk [Member]
Loans receivable, other information [Abstract]
Percentage of loan portfolio secured by property in Oklahoma (in hundredths)		12.00%
Residential mortgage [Member]
Loan receivables disclosure [Abstract]
Loans, fixed rate of interest		$ 1,592,249	1,608,655	1,589,013
Loans, variable rate of interest		337,576	317,584	311,231
Loans, non-accrual		41,917	47,447	45,506
Total		1,971,742	1,973,686	1,945,750
Residential mortgage [Member] | Permanent mortgage [Member]
Loan receivables disclosure [Abstract]
Total		$ 1,094,926	1,043,435	1,013,965
Loans receivable, other information [Abstract]
Minimum FICO required for jumbo loan approval		720
Maximum debt-to-income ratio on jumbo loans (in hundredths)		38.00%
Minimum loan-to-value ratio on jumbo loans (in hundredths)		60.00%
Maximum loan-to-value ratio on jumbo loans (in hundredths)		100.00%
Minimum period for fixed rate on variable rate jumbo loans (in years)		3 years
Maximum period for fixed rate on variable rate jumbo loans (in years)		10 years
Residential mortgage [Member] | Permanent mortgages guaranteed by US government agencies [Member]
Loan receivables disclosure [Abstract]
Total		$ 180,718	197,506	187,370
Residential mortgage [Member] | Home equity [Member]
Loan receivables disclosure [Abstract]
Total		$ 696,098	732,745	744,415
Loans receivable, other information [Abstract]
Percentage of home equity portfolio comprised of first lien loans		61.00%
Percentage of home equity portfolio comprised of junior lien loans		39.00%
Percentage of junior lien home equity loans that are amortizing term loans		44.00%
Percentage of junior lien home equity loans that are revolving lines of credit		56.00%
Home equity loans, description		Home equity loans generally require a minimum FICO score of 700 and a maximum DTI of 40 percent.
Home equity loans, maximum		$ 400
Home equity loans, revolving period		5 years
Home equity loans, amortization period following revolving period		15 years
Home equity loans, discretionary additional revolving period		5 years
Personal [Member]
Loan receivables disclosure [Abstract]
Loans, fixed rate of interest		$ 163,067	154,517	153,750
Loans, variable rate of interest		833,605	810,990	793,003
Loans, non-accrual		269	269	255
Total		$ 996,941	$ 965,776	$ 947,008
[1] Excludes residential mortgage loans guaranteed by agencies of the U.S. government

X

- Definition

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

+ References

No definition available.

+ Details

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

X

- 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

X

- Definition

Represents additional revolving period that may be extended at the discretion of management following the initial revolving period for home equity loans.

+ References

No definition available.

+ Details

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

X

- 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

X

- Definition

The generally accepted maximum loan amount for a home equity loan issued by the Company.

+ References

No definition available.

+ Details

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

X

- 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

X

- 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

X

- 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

X

- 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

X

- 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

X

- 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

X

- 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

X

- 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

X

- 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

X

- 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

X

- 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

X

- 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

X

- 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

X

- 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

X

- 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

X

- 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

X

- 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

X

- Definition

Reflects the percentage of the loan portfolio attributed to Oklahoma.

+ References

No definition available.

+ Details

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

X

- Definition

Reflects the percentage of the loan portfolio attributed to Texas.

+ References

No definition available.

+ Details

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

X

- 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

X

- Definition

Recorded investment in financing receivables that are 90 days or more past due and still accruing.

+ 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 (d)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5111-111524

+ Details

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

X

- 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

X

- References

No definition available.

+ Details

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

X

- 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=82891408&loc=d3e4428-111522

+ Details

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

X

- 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=84173941&loc=d3e5111-111524

+ Details

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

X

- References

No definition available.

+ Details

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

X

- Definition

Amount of loan with fixed rate of interest.

+ 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=82891408&loc=d3e4428-111522

+ Details

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

X

- Definition

Amount of loan with variable or adjustable rate of interest.

+ 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=82891408&loc=d3e4428-111522

+ Details

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

X

- 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

X

- Details

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

X

- Details

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

X

- Details

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

X

- Details

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

X

- Details

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

X

- Details

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

X

- Details

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

X

- Details

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

X

- Details

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

X

- Details

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

X

- Details

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

X

- Details

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

X

- Details

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

X

- Details

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

X

- Details

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