Mortgage Banking Activities Mortgage Banking Activities, Loans Serviced for Others (Details) (USD $) In Thousands, unless otherwise specified
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Dec. 31, 2014
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Financing Receivable, Recorded Investment, Aging [Abstract] |
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Mortgage Loans Serviced For Others, Current |
$ 15,832,249bokf_LoansServicedForOthersCurrent |
Mortgage Loans Serviced For Others, 30 To 59 Days Past Due |
204,324bokf_LoansServicedForOthers30To59DaysPastDue |
Mortgage Loans Serviced For Others, 60 To 89 Days Past Due |
51,247bokf_LoansServicedForOthers60To89DaysPastDue |
Mortgage Loans Serviced For Others, Greater Than 90 Days or More Past Due |
75,067bokf_LoansServicedForOtherstEqualToGreaterThan90DaysPastDue |
Mortgage Loans Serviced For Others |
16,162,887bokf_LoansServicedForOthers |
Federal Home Loan Mortgage Corporation Certificates and Obligations (FHLMC) [Member] |
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Financing Receivable, Recorded Investment, Aging [Abstract] |
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Mortgage Loans Serviced For Others, Current |
5,289,078bokf_LoansServicedForOthersCurrent / bokf_AgingOfMortgageLoansServicedForOthersByInvestorAxis = us-gaap_FederalHomeLoanMortgageCorporationCertificatesAndObligationsFHLMCMember |
Mortgage Loans Serviced For Others, 30 To 59 Days Past Due |
37,881bokf_LoansServicedForOthers30To59DaysPastDue / bokf_AgingOfMortgageLoansServicedForOthersByInvestorAxis = us-gaap_FederalHomeLoanMortgageCorporationCertificatesAndObligationsFHLMCMember |
Mortgage Loans Serviced For Others, 60 To 89 Days Past Due |
9,418bokf_LoansServicedForOthers60To89DaysPastDue / bokf_AgingOfMortgageLoansServicedForOthersByInvestorAxis = us-gaap_FederalHomeLoanMortgageCorporationCertificatesAndObligationsFHLMCMember |
Mortgage Loans Serviced For Others, Greater Than 90 Days or More Past Due |
33,837bokf_LoansServicedForOtherstEqualToGreaterThan90DaysPastDue / bokf_AgingOfMortgageLoansServicedForOthersByInvestorAxis = us-gaap_FederalHomeLoanMortgageCorporationCertificatesAndObligationsFHLMCMember |
Mortgage Loans Serviced For Others |
5,370,214bokf_LoansServicedForOthers / bokf_AgingOfMortgageLoansServicedForOthersByInvestorAxis = us-gaap_FederalHomeLoanMortgageCorporationCertificatesAndObligationsFHLMCMember |
Federal National Mortgage Association Certificates and Obligations (FNMA) [Member] |
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Financing Receivable, Recorded Investment, Aging [Abstract] |
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Mortgage Loans Serviced For Others, Current |
5,200,509bokf_LoansServicedForOthersCurrent / bokf_AgingOfMortgageLoansServicedForOthersByInvestorAxis = us-gaap_FederalNationalMortgageAssociationCertificatesAndObligationsFNMAMember |
Mortgage Loans Serviced For Others, 30 To 59 Days Past Due |
27,089bokf_LoansServicedForOthers30To59DaysPastDue / bokf_AgingOfMortgageLoansServicedForOthersByInvestorAxis = us-gaap_FederalNationalMortgageAssociationCertificatesAndObligationsFNMAMember |
Mortgage Loans Serviced For Others, 60 To 89 Days Past Due |
5,736bokf_LoansServicedForOthers60To89DaysPastDue / bokf_AgingOfMortgageLoansServicedForOthersByInvestorAxis = us-gaap_FederalNationalMortgageAssociationCertificatesAndObligationsFNMAMember |
Mortgage Loans Serviced For Others, Greater Than 90 Days or More Past Due |
22,087bokf_LoansServicedForOtherstEqualToGreaterThan90DaysPastDue / bokf_AgingOfMortgageLoansServicedForOthersByInvestorAxis = us-gaap_FederalNationalMortgageAssociationCertificatesAndObligationsFNMAMember |
Mortgage Loans Serviced For Others |
5,255,421bokf_LoansServicedForOthers / bokf_AgingOfMortgageLoansServicedForOthersByInvestorAxis = us-gaap_FederalNationalMortgageAssociationCertificatesAndObligationsFNMAMember |
Government National Mortgage Association Certificates and Obligations (GNMA) [Member] |
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Financing Receivable, Recorded Investment, Aging [Abstract] |
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Mortgage Loans Serviced For Others, Current |
4,920,064bokf_LoansServicedForOthersCurrent / bokf_AgingOfMortgageLoansServicedForOthersByInvestorAxis = us-gaap_GovernmentNationalMortgageAssociationCertificatesAndObligationsGNMAMember |
Mortgage Loans Serviced For Others, 30 To 59 Days Past Due |
132,680bokf_LoansServicedForOthers30To59DaysPastDue / bokf_AgingOfMortgageLoansServicedForOthersByInvestorAxis = us-gaap_GovernmentNationalMortgageAssociationCertificatesAndObligationsGNMAMember |
Mortgage Loans Serviced For Others, 60 To 89 Days Past Due |
34,602bokf_LoansServicedForOthers60To89DaysPastDue / bokf_AgingOfMortgageLoansServicedForOthersByInvestorAxis = us-gaap_GovernmentNationalMortgageAssociationCertificatesAndObligationsGNMAMember |
Mortgage Loans Serviced For Others, Greater Than 90 Days or More Past Due |
13,594bokf_LoansServicedForOtherstEqualToGreaterThan90DaysPastDue / bokf_AgingOfMortgageLoansServicedForOthersByInvestorAxis = us-gaap_GovernmentNationalMortgageAssociationCertificatesAndObligationsGNMAMember |
Mortgage Loans Serviced For Others |
5,100,940bokf_LoansServicedForOthers / bokf_AgingOfMortgageLoansServicedForOthersByInvestorAxis = us-gaap_GovernmentNationalMortgageAssociationCertificatesAndObligationsGNMAMember |
Other Investor Loans [Member] |
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Financing Receivable, Recorded Investment, Aging [Abstract] |
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Mortgage Loans Serviced For Others, Current |
422,598bokf_LoansServicedForOthersCurrent / bokf_AgingOfMortgageLoansServicedForOthersByInvestorAxis = bokf_OtherInvestorLoansMember |
Mortgage Loans Serviced For Others, 30 To 59 Days Past Due |
6,674bokf_LoansServicedForOthers30To59DaysPastDue / bokf_AgingOfMortgageLoansServicedForOthersByInvestorAxis = bokf_OtherInvestorLoansMember |
Mortgage Loans Serviced For Others, 60 To 89 Days Past Due |
1,491bokf_LoansServicedForOthers60To89DaysPastDue / bokf_AgingOfMortgageLoansServicedForOthersByInvestorAxis = bokf_OtherInvestorLoansMember |
Mortgage Loans Serviced For Others, Greater Than 90 Days or More Past Due |
5,549bokf_LoansServicedForOtherstEqualToGreaterThan90DaysPastDue / bokf_AgingOfMortgageLoansServicedForOthersByInvestorAxis = bokf_OtherInvestorLoansMember |
Mortgage Loans Serviced For Others |
$ 436,312bokf_LoansServicedForOthers / bokf_AgingOfMortgageLoansServicedForOthersByInvestorAxis = bokf_OtherInvestorLoansMember |