Commitments and Contingent Liabilities (Details) (USD $)
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12 Months Ended | ||
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Dec. 31, 2014
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Dec. 31, 2013
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Dec. 31, 2012
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Loss Contingencies [Line Items] | |||
Operating Leases, Rent Expense, Net | $ 25,000,000us-gaap_OperatingLeasesRentExpenseNet | $ 23,500,000us-gaap_OperatingLeasesRentExpenseNet | $ 21,700,000us-gaap_OperatingLeasesRentExpenseNet |
Operating Leases, Future Minimum Payments, Due in 2015 | 26,000,000us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent | ||
Operating Leases, Future Minimum Payments, Due in 2016 | 22,900,000us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears | ||
Operating Leases, Future Minimum Payments, Due in 2017 | 19,300,000us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears | ||
Operating Leases, Future Minimum Payments, Due in 2018 | 15,100,000us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears | ||
Operating Leases, Future Minimum Payments, Due in 2019 | 13,000,000us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears | ||
Operating Leases, Future Minimum Payments, Due Thereafter | 104,800,000us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter | ||
Minimum Average Cash Balance Required to be Maintained at Federal Reserve by Subsidiary Bank | 1,500,000,000bokf_MinimumAverageCashBalanceRequiredToBeMaintainedAtFederalReserveBySubsidiaryBank | 830,000,000bokf_MinimumAverageCashBalanceRequiredToBeMaintainedAtFederalReserveBySubsidiaryBank | |
Parent Company [Member] | Visa Membership [Member] | |||
Loss Contingencies [Line Items] | |||
Number of Visa Class B Shares Owned by Entity (in shares) | 251,837bokf_CommonStockClassBSharesOwned / dei_LegalEntityAxis = us-gaap_ParentCompanyMember / us-gaap_LossContingenciesByNatureOfContingencyAxis = bokf_VisaMembershipMember |
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Number of Visa Class A Shares Visa Class B Shares Are Convertible To (in shares) | 103,782bokf_NumberofVisaClassASharesVisaClassBSharesAreConvertibleTo / dei_LegalEntityAxis = us-gaap_ParentCompanyMember / us-gaap_LossContingenciesByNatureOfContingencyAxis = bokf_VisaMembershipMember |
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Cavanal Hill Funds [Member] | |||
Loss Contingencies [Line Items] | |||
Mutual Fund Investment in US Treasury Securities | 1,100,000,000bokf_MutualFundAssetsManagedInvestmentInUsTreasurySecurities / dei_LegalEntityAxis = bokf_CavanalHillFundsMember |
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Mutual Fund Investment in Cash Management | 1,300,000,000bokf_MutualFundAssetsManagedInCashManagement / dei_LegalEntityAxis = bokf_CavanalHillFundsMember |
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Mutual Fund Investment in Tax-Free Money Market Funds | $ 258,000,000bokf_MutualFundManagedAssetsInTaxFreeMoneyMarketFunds / dei_LegalEntityAxis = bokf_CavanalHillFundsMember |
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The Net Asset Value of Units in Mutual Funds (per unit) | 1.00bokf_MutualFundsManagedNetAssetValueOfUnitsInMutualFunds / dei_LegalEntityAxis = bokf_CavanalHillFundsMember |
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Number of common stock class B owned by the entity No definition available.
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Minimum Average Cash Balance Required to be Maintained at Federal Reserve by Subsidiary Bank No definition available.
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Carrying amount of mutual fund assets in cash management No definition available.
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Mutual Fund Assets Managed investment in US Treasury Securities No definition available.
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Amount of Mutual Fund Managed Assets in Tax-Free Money Market Funds No definition available.
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Managed Net Asset Value of Units in Mutual Funds No definition available.
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Represents the number of Visa Class A shares that Visa Class B shares held by the Company are convertible to. No definition available.
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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Rental expense for the reporting period incurred under operating leases, including minimum and any contingent rent expense, net of related sublease income. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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