XML 67 R64.htm IDEA: XBRL DOCUMENT v2.4.1.9
Fair Value Measurements, Financial Instruments (Details) (USD $)
Mar. 31, 2015
Dec. 31, 2014
Mar. 31, 2014
Dec. 31, 2013
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
Interest-bearing cash and cash equivalents $ 2,119,987,000bokf_Interestbearingcashandcashequivalents $ 1,925,266,000bokf_Interestbearingcashandcashequivalents $ 708,571,000bokf_Interestbearingcashandcashequivalents  
Trading securities 118,044,000us-gaap_TradingSecurities 188,700,000us-gaap_TradingSecurities 86,571,000us-gaap_TradingSecurities  
Investment securities 634,587,000us-gaap_HeldToMaturitySecurities [1] 652,360,000us-gaap_HeldToMaturitySecurities [2] 668,976,000us-gaap_HeldToMaturitySecurities [3]  
Available for sale securities 9,158,175,000us-gaap_AvailableForSaleSecurities 8,978,945,000us-gaap_AvailableForSaleSecurities 9,933,723,000us-gaap_AvailableForSaleSecurities  
Fair value option securities 434,077,000bokf_FairValueOptionSecurities 311,597,000bokf_FairValueOptionSecurities 160,884,000bokf_FairValueOptionSecurities  
Residential mortgage loans held for sale 513,196,000us-gaap_LoansHeldForSaleMortgages 304,182,000us-gaap_LoansHeldForSaleMortgages 226,512,000us-gaap_LoansHeldForSaleMortgages  
Loans 14,684,136,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount 14,208,037,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount 13,077,854,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount  
Allowance for loan losses (197,686,000)us-gaap_LoansAndLeasesReceivableAllowance (189,056,000)us-gaap_LoansAndLeasesReceivableAllowance (188,318,000)us-gaap_LoansAndLeasesReceivableAllowance (185,396,000)us-gaap_LoansAndLeasesReceivableAllowance
Loans, net of allowance 14,486,450,000us-gaap_LoansAndLeasesReceivableNetReportedAmount 14,018,981,000us-gaap_LoansAndLeasesReceivableNetReportedAmount 12,889,536,000us-gaap_LoansAndLeasesReceivableNetReportedAmount  
Mortgage servicing rights 175,051,000us-gaap_ServicingAssetAtFairValueAmount 171,976,000us-gaap_ServicingAssetAtFairValueAmount 153,774,000us-gaap_ServicingAssetAtFairValueAmount 153,333,000us-gaap_ServicingAssetAtFairValueAmount
Derviative contracts, net of cash margin, Assets, Fair value 462,386,000us-gaap_DerivativeAssets 361,874,000us-gaap_DerivativeAssets 218,507,000us-gaap_DerivativeAssets  
Time deposits 2,651,778,000us-gaap_TimeDeposits 2,608,716,000us-gaap_TimeDeposits 2,662,174,000us-gaap_TimeDeposits  
Subordinated debentures 348,030,000us-gaap_SubordinatedDebt 347,983,000us-gaap_SubordinatedDebt 347,846,000us-gaap_SubordinatedDebt  
Derivative contracts, net of cash margin, Liabilities, Fair Value 419,351,000us-gaap_DerivativeLiabilities 354,554,000us-gaap_DerivativeLiabilities 185,499,000us-gaap_DerivativeLiabilities  
Fair Value Assumptions and Methodology for Assets and Liabilities [Abstract]        
Specific allocation of allowance for loan losses included in fair value of loans 170,000,000bokf_SpecificAllocationOfAllowanceForLoanLossesIncludedInFairValueOfLoans 161,000,000bokf_SpecificAllocationOfAllowanceForLoanLossesIncludedInFairValueOfLoans 161,000,000bokf_SpecificAllocationOfAllowanceForLoanLossesIncludedInFairValueOfLoans  
Commercial [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
Loans 9,391,163,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember		 9,095,670,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember		 8,051,706,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember		  
Allowance for loan losses (101,411,000)us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember		 (90,875,000)us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember		 (85,246,000)us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember		 (79,180,000)us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
Commercial Real Estate [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
Loans 2,935,464,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		 2,728,150,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		 2,631,407,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		  
Allowance for loan losses (40,819,000)us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		 (42,445,000)us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		 (41,589,000)us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		 (41,573,000)us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
Residential Mortgage [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
Loans 1,926,999,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember		 1,949,512,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember		 2,018,675,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember		  
Allowance for loan losses (23,244,000)us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember		 (23,458,000)us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember		 (28,307,000)us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember		 (29,465,000)us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember
Consumer [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
Loans 430,510,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		 434,705,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		 376,066,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		  
Allowance for loan losses (4,139,000)us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		 (4,233,000)us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		 (6,211,000)us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		 (6,965,000)us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
U.S. Government agency debentures [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
Trading securities 26,283,000us-gaap_TradingSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USTreasuryAndGovernmentMember		 85,092,000us-gaap_TradingSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USTreasuryAndGovernmentMember		 28,588,000us-gaap_TradingSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USTreasuryAndGovernmentMember		  
U.S. agency residential mortgage-backed securities [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
Trading securities 17,179,000us-gaap_TradingSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember		 31,199,000us-gaap_TradingSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember		 23,595,000us-gaap_TradingSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember		  
Available for sale securities 6,717,569,000us-gaap_AvailableForSaleSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember		 6,646,884,000us-gaap_AvailableForSaleSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember		 7,475,569,000us-gaap_AvailableForSaleSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember		  
Fair value option securities 434,077,000bokf_FairValueOptionSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember		 311,597,000bokf_FairValueOptionSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember		 156,525,000bokf_FairValueOptionSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember		  
Municipal and other tax-exempt securities [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
Trading securities 54,164,000us-gaap_TradingSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember		 38,951,000us-gaap_TradingSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember		 27,280,000us-gaap_TradingSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember		  
Investment securities 396,063,000us-gaap_HeldToMaturitySecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember		 [1] 405,090,000us-gaap_HeldToMaturitySecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember		 [2] 440,303,000us-gaap_HeldToMaturitySecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember		 [3]  
Available for sale securities 60,818,000us-gaap_AvailableForSaleSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember		 63,557,000us-gaap_AvailableForSaleSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember		 70,065,000us-gaap_AvailableForSaleSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember		  
Other trading securities [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
Trading securities 20,418,000us-gaap_TradingSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= bokf_OtherTradingSecuritiesMember		 33,458,000us-gaap_TradingSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= bokf_OtherTradingSecuritiesMember		 7,108,000us-gaap_TradingSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= bokf_OtherTradingSecuritiesMember		  
U.S. Treasury [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
Available for sale securities 1,001,000us-gaap_AvailableForSaleSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USTreasurySecuritiesMember		 1,005,000us-gaap_AvailableForSaleSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USTreasurySecuritiesMember		 1,034,000us-gaap_AvailableForSaleSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USTreasurySecuritiesMember		  
Privately issued residential mortgage-backed securities [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
Available for sale securities 160,031,000us-gaap_AvailableForSaleSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember		 165,957,000us-gaap_AvailableForSaleSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember		 189,248,000us-gaap_AvailableForSaleSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember		  
Commercial mortgage-backed securities guaranteed by U.S. government agencies [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
Available for sale securities 2,164,842,000us-gaap_AvailableForSaleSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_CommercialMortgageBackedSecuritiesMember		 2,048,609,000us-gaap_AvailableForSaleSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_CommercialMortgageBackedSecuritiesMember		 2,123,762,000us-gaap_AvailableForSaleSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_CommercialMortgageBackedSecuritiesMember		  
Other debt securities [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
Investment securities 204,979,000us-gaap_HeldToMaturitySecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_OtherDebtSecuritiesMember		 [1] 211,520,000us-gaap_HeldToMaturitySecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_OtherDebtSecuritiesMember		 [2] 182,756,000us-gaap_HeldToMaturitySecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_OtherDebtSecuritiesMember		 [3]  
Available for sale securities 9,155,000us-gaap_AvailableForSaleSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_OtherDebtSecuritiesMember		 9,212,000us-gaap_AvailableForSaleSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_OtherDebtSecuritiesMember		 35,119,000us-gaap_AvailableForSaleSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_OtherDebtSecuritiesMember		  
Fair value option securities 0bokf_FairValueOptionSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_OtherDebtSecuritiesMember		 0bokf_FairValueOptionSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_OtherDebtSecuritiesMember		 4,359,000bokf_FairValueOptionSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_OtherDebtSecuritiesMember		  
Perpetual preferred stock [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
Available for sale securities 24,983,000us-gaap_AvailableForSaleSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_PreferredStockMember		 24,277,000us-gaap_AvailableForSaleSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_PreferredStockMember		 24,281,000us-gaap_AvailableForSaleSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_PreferredStockMember		  
Equity securities and mutual funds [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
Available for sale securities 19,776,000us-gaap_AvailableForSaleSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= bokf_EquitySecuritiesAndMutualFundsMember		 19,444,000us-gaap_AvailableForSaleSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= bokf_EquitySecuritiesAndMutualFundsMember		 14,645,000us-gaap_AvailableForSaleSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= bokf_EquitySecuritiesAndMutualFundsMember		  
Carrying (Reported) Amount, Fair Value Disclosure [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
Cash and due from banks 490,683,000us-gaap_CashAndCashEquivalentsFairValueDisclosure
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember		 550,576,000us-gaap_CashAndCashEquivalentsFairValueDisclosure
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember		 645,435,000us-gaap_CashAndCashEquivalentsFairValueDisclosure
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember		  
Interest-bearing cash and cash equivalents 2,119,987,000bokf_Interestbearingcashandcashequivalents
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember		 1,925,266,000bokf_Interestbearingcashandcashequivalents
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember		 708,571,000bokf_Interestbearingcashandcashequivalents
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember		  
Trading securities 118,044,000us-gaap_TradingSecurities
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember		 188,700,000us-gaap_TradingSecurities
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember		 86,571,000us-gaap_TradingSecurities
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember		  
Investment securities 634,587,000us-gaap_HeldToMaturitySecurities
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember		 652,360,000us-gaap_HeldToMaturitySecurities
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember		 668,976,000us-gaap_HeldToMaturitySecurities
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember		  
Available for sale securities 9,158,175,000us-gaap_AvailableForSaleSecurities
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember		 8,978,945,000us-gaap_AvailableForSaleSecurities
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember		 9,933,723,000us-gaap_AvailableForSaleSecurities
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember		  
Fair value option securities 434,077,000bokf_FairValueOptionSecurities
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember		 311,597,000bokf_FairValueOptionSecurities
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember		 160,884,000bokf_FairValueOptionSecurities
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember		  
Residential mortgage loans held for sale 513,196,000us-gaap_LoansHeldForSaleMortgages
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember		 304,182,000us-gaap_LoansHeldForSaleMortgages
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember		 226,512,000us-gaap_LoansHeldForSaleMortgages
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember		  
Loans 14,684,136,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember		 14,208,037,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember		 13,077,854,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember		  
Allowance for loan losses (197,686,000)us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember		 (189,056,000)us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember		 (188,318,000)us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember		  
Loans, net of allowance 14,486,450,000us-gaap_LoansAndLeasesReceivableNetReportedAmount
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember		 14,018,981,000us-gaap_LoansAndLeasesReceivableNetReportedAmount
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember		 12,889,536,000us-gaap_LoansAndLeasesReceivableNetReportedAmount
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember		  
Mortgage servicing rights 175,051,000us-gaap_ServicingAssetAtFairValueAmount
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember		 171,976,000us-gaap_ServicingAssetAtFairValueAmount
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember		 153,774,000us-gaap_ServicingAssetAtFairValueAmount
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember		  
Derviative contracts, net of cash margin, Assets, Fair value 462,386,000us-gaap_DerivativeAssets
/ us-gaap_FairValueByMeasurementBasisAxis
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Other assets, private equity funds 25,565,000us-gaap_AlternativeInvestmentsFairValueDisclosure
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Deposits with no stated maturity 18,501,569,000bokf_DepositsNoStatedMaturityFairValueDisclosure
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Time deposits 2,651,778,000us-gaap_TimeDeposits
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Other borrowed funds 4,691,033,000us-gaap_OtherLiabilitiesFairValueDisclosure
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Subordinated debentures 348,030,000us-gaap_SubordinatedDebt
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Derivative contracts, net of cash margin, Liabilities, Fair Value 419,351,000us-gaap_DerivativeLiabilities
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Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
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Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
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Carrying (Reported) Amount, Fair Value Disclosure [Member] | Residential Mortgage [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
Loans 1,926,999,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
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Carrying (Reported) Amount, Fair Value Disclosure [Member] | Consumer [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
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Carrying (Reported) Amount, Fair Value Disclosure [Member] | U.S. Government agency debentures [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
Trading securities 26,283,000us-gaap_TradingSecurities
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Carrying (Reported) Amount, Fair Value Disclosure [Member] | U.S. agency residential mortgage-backed securities [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
Trading securities 17,179,000us-gaap_TradingSecurities
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Investment securities 33,545,000us-gaap_HeldToMaturitySecurities
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Available for sale securities 6,717,569,000us-gaap_AvailableForSaleSecurities
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Fair value option securities 434,077,000bokf_FairValueOptionSecurities
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Carrying (Reported) Amount, Fair Value Disclosure [Member] | Municipal and other tax-exempt securities [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
Trading securities 54,164,000us-gaap_TradingSecurities
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Carrying (Reported) Amount, Fair Value Disclosure [Member] | Other trading securities [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
Trading securities 20,418,000us-gaap_TradingSecurities
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Carrying (Reported) Amount, Fair Value Disclosure [Member] | U.S. Treasury [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
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Carrying (Reported) Amount, Fair Value Disclosure [Member] | Privately issued residential mortgage-backed securities [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
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Carrying (Reported) Amount, Fair Value Disclosure [Member] | Commercial mortgage-backed securities guaranteed by U.S. government agencies [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
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Carrying (Reported) Amount, Fair Value Disclosure [Member] | Other debt securities [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
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Carrying (Reported) Amount, Fair Value Disclosure [Member] | Perpetual preferred stock [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
Available for sale securities 24,983,000us-gaap_AvailableForSaleSecurities
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Carrying (Reported) Amount, Fair Value Disclosure [Member] | Equity securities and mutual funds [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
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Estimate of Fair Value, Fair Value Disclosure [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
Cash and due from banks 490,683,000us-gaap_CashAndCashEquivalentsFairValueDisclosure
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Interest-bearing cash and cash equivalents 2,119,987,000bokf_Interestbearingcashandcashequivalents
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Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
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Estimate of Fair Value, Fair Value Disclosure [Member] | Residential Mortgage [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
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Estimate of Fair Value, Fair Value Disclosure [Member] | Consumer [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
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Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. Government agency debentures [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
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Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
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Estimate of Fair Value, Fair Value Disclosure [Member] | Municipal and other tax-exempt securities [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
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Estimate of Fair Value, Fair Value Disclosure [Member] | Other trading securities [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
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Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. Treasury [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
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Estimate of Fair Value, Fair Value Disclosure [Member] | Privately issued residential mortgage-backed securities [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
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Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial mortgage-backed securities guaranteed by U.S. government agencies [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]        
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Estimate of Fair Value, Fair Value Disclosure [Member] | Other debt securities [Member]        
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[1] Carrying value includes $436 thousand of net unrealized gain which remains in Accumulated other comprehensive income (“AOCI”) in the Consolidated Balance Sheets related to certain securities transferred from the Available for Sale securities portfolio to the Investment securities portfolio in 2011.
[2] Carrying value includes $615 thousand of net unrealized gain which remains in Accumulated other comprehensive income (“AOCI”) in the Consolidated Balance Sheets related to certain securities transferred from the Available for Sale securities portfolio to the Investment securities portfolio in 2011.
[3] Carrying value includes $1.4 million of net unrealized gain which remains in Accumulated other comprehensive income (“AOCI”) in the Consolidated Balance Sheets related to certain securities transferred from the Available for Sale securities portfolio to the Investment securities portfolio in 2011.