Loans and Allowance for Credit Losses, Loans by Portfolio Type (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Loan receivables disclosure [Abstract]
Loans, fixed rate of interest	$ 6,697,080	$ 6,633,234
Loans, variable rate of interest	17,355,965	17,126,265
Loans, non-accrual	119,515	145,469
Total	24,172,560	23,904,968
Credit Commitments [Abstract]
Outstanding commitments to extend credit	14,400,000
Outstanding standby letters of credit	734,000
Commercial [Member]
Loan receivables disclosure [Abstract]
Loans, fixed rate of interest	3,597,543	3,558,563
Loans, variable rate of interest	11,460,704	11,135,075
Loans, non-accrual	74,620	110,131
Total	15,132,867	14,803,769
Commercial real estate [Member]
Loan receivables disclosure [Abstract]
Loans, fixed rate of interest	784,301	791,757
Loans, variable rate of interest	4,430,289	4,538,570
Loans, non-accrual	22,087	7,320
Total	5,236,677	5,337,647
Loans to individuals [Member]
Loan receivables disclosure [Abstract]
Loans, fixed rate of interest	2,315,236	2,282,914
Loans, variable rate of interest	1,464,972	1,452,620
Loans, non-accrual	22,808	28,018
Total	$ 3,803,016	$ 3,763,552

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

No definition available.

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

- 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
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481990/310-10-45-2

+ Details

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

- 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
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481962/310-10-50-7

+ Details

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

- 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_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
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=bokf_LoanstoindividualsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: