XML 95 R63.htm IDEA: XBRL DOCUMENT v2.4.1.9
Loans and Allowances for Credit Losses, Credit Quality Indicators (Details) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment $ 12,336,710bokf_InternallyRiskGradedRecordedInvestment $ 10,789,740bokf_InternallyRiskGradedRecordedInvestment    
Non-Graded, Recorded Investment 1,871,327bokf_NonGradedRecordedInvestment 2,002,524bokf_NonGradedRecordedInvestment    
Total 14,208,037us-gaap_LoansAndLeasesReceivableGrossCarryingAmount 12,792,264us-gaap_LoansAndLeasesReceivableGrossCarryingAmount    
Related Allowance [Abstract]        
Internally Risk Graded, Related Allowance 137,032bokf_InternallyRiskGradedAllowance 127,961bokf_InternallyRiskGradedAllowance    
Non-Graded, Related Allowance 23,979bokf_NonGradedAllowance 29,222bokf_NonGradedAllowance    
Total, Related Allowance 189,056us-gaap_LoansAndLeasesReceivableAllowance 185,396us-gaap_LoansAndLeasesReceivableAllowance 215,507us-gaap_LoansAndLeasesReceivableAllowance 253,481us-gaap_LoansAndLeasesReceivableAllowance
Performing [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 12,222,486bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 10,650,784bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Non-Graded, Recorded Investment 1,825,709bokf_NonGradedRecordedInvestment
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 1,966,324bokf_NonGradedRecordedInvestment
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Potential Problem [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 79,071bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		 74,007bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		    
Nonaccrual [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 35,153bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 64,949bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Non-Graded, Recorded Investment 45,618bokf_NonGradedRecordedInvestment
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 36,200bokf_NonGradedRecordedInvestment
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Commercial [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 9,073,030bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialLoanMember		 7,888,219bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialLoanMember		    
Non-Graded, Recorded Investment 22,640bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialLoanMember		 55,002bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialLoanMember		    
Total 9,095,670us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialLoanMember		 7,943,221us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialLoanMember		    
Related Allowance [Abstract]        
Internally Risk Graded, Related Allowance 90,085bokf_InternallyRiskGradedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialLoanMember		 78,250bokf_InternallyRiskGradedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialLoanMember		    
Non-Graded, Related Allowance 790bokf_NonGradedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialLoanMember		 930bokf_NonGradedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialLoanMember		    
Total, Related Allowance 90,875us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialLoanMember		 79,180us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialLoanMember		    
Commercial [Member] | Performing [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 9,008,360bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 7,841,108bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Non-Graded, Recorded Investment 22,532bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 54,929bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Commercial [Member] | Potential Problem [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 51,251bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		 30,424bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		    
Commercial [Member] | Nonaccrual [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 13,419bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 16,687bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Non-Graded, Recorded Investment 108bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 73bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Energy [Member]        
Recorded Investment [Abstract]        
Total 2,860,428us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_EnergyMember		 2,351,760us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_EnergyMember		    
Energy [Member] | Performing [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 2,843,093bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_EnergyMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 2,347,519bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_EnergyMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Non-Graded, Recorded Investment 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_EnergyMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_EnergyMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Energy [Member] | Potential Problem [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 15,919bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_EnergyMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		 2,381bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_EnergyMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		    
Energy [Member] | Nonaccrual [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 1,416bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_EnergyMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 1,860bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_EnergyMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Non-Graded, Recorded Investment 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_EnergyMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_EnergyMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Services [Member]        
Recorded Investment [Abstract]        
Total 2,518,229us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_ServicesMember		 2,282,210us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_ServicesMember		    
Services [Member] | Performing [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 2,497,888bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_ServicesMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 2,265,984bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_ServicesMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Non-Graded, Recorded Investment 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_ServicesMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_ServicesMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Services [Member] | Potential Problem [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 15,140bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_ServicesMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		 11,304bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_ServicesMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		    
Services [Member] | Nonaccrual [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 5,201bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_ServicesMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 4,922bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_ServicesMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Non-Graded, Recorded Investment 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_ServicesMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_ServicesMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Wholesale/retail [Member]        
Recorded Investment [Abstract]        
Total 1,313,316us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_WholesaleAndRetailMember		 1,201,364us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_WholesaleAndRetailMember		    
Wholesale/retail [Member] | Performing [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 1,301,026bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_WholesaleAndRetailMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 1,191,791bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_WholesaleAndRetailMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Non-Graded, Recorded Investment 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_WholesaleAndRetailMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_WholesaleAndRetailMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Wholesale/retail [Member] | Potential Problem [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 8,141bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_WholesaleAndRetailMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		 2,604bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_WholesaleAndRetailMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		    
Wholesale/retail [Member] | Nonaccrual [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 4,149bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_WholesaleAndRetailMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 6,969bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_WholesaleAndRetailMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Non-Graded, Recorded Investment 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_WholesaleAndRetailMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_WholesaleAndRetailMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Manufacturing [Member]        
Recorded Investment [Abstract]        
Total 532,594us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_ManufacturingMember		 391,751us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_ManufacturingMember		    
Manufacturing [Member] | Performing [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 527,951bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_ManufacturingMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 381,794bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_ManufacturingMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Non-Graded, Recorded Investment 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_ManufacturingMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_ManufacturingMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Manufacturing [Member] | Potential Problem [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 4,193bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_ManufacturingMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		 9,365bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_ManufacturingMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		    
Manufacturing [Member] | Nonaccrual [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 450bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_ManufacturingMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 592bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_ManufacturingMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Non-Graded, Recorded Investment 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_ManufacturingMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_ManufacturingMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Healthcare [Member]        
Recorded Investment [Abstract]        
Total 1,454,969us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_HealthcareMember		 1,274,246us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_HealthcareMember		    
Healthcare [Member] | Performing [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 1,449,024bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_HealthcareMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 1,272,626bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_HealthcareMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Non-Graded, Recorded Investment 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_HealthcareMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_HealthcareMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Healthcare [Member] | Potential Problem [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 4,565bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_HealthcareMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		 34bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_HealthcareMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		    
Healthcare [Member] | Nonaccrual [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 1,380bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_HealthcareMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 1,586bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_HealthcareMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Non-Graded, Recorded Investment 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_HealthcareMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_HealthcareMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Other commercial and industrial [Member]        
Recorded Investment [Abstract]        
Total 416,134us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_OtherCommercialAndIndustrialMember		 441,890us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_OtherCommercialAndIndustrialMember		    
Other commercial and industrial [Member] | Performing [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 389,378bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_OtherCommercialAndIndustrialMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 381,394bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_OtherCommercialAndIndustrialMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Non-Graded, Recorded Investment 22,532bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_OtherCommercialAndIndustrialMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 54,929bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_OtherCommercialAndIndustrialMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Other commercial and industrial [Member] | Potential Problem [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 3,293bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_OtherCommercialAndIndustrialMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		 4,736bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_OtherCommercialAndIndustrialMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		    
Other commercial and industrial [Member] | Nonaccrual [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 823bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_OtherCommercialAndIndustrialMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 758bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_OtherCommercialAndIndustrialMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Non-Graded, Recorded Investment 108bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_OtherCommercialAndIndustrialMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 73bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_OtherCommercialAndIndustrialMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Commercial Real Estate [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 2,728,150bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember		 2,415,353bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember		    
Non-Graded, Recorded Investment 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember		 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember		    
Total 2,728,150us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember		 2,415,353us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember		    
Related Allowance [Abstract]        
Internally Risk Graded, Related Allowance 42,445bokf_InternallyRiskGradedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember		 41,573bokf_InternallyRiskGradedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember		    
Non-Graded, Related Allowance 0bokf_NonGradedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember		 0bokf_NonGradedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember		    
Total, Related Allowance 42,445us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember		 41,573us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember		    
Commercial Real Estate [Member] | Performing [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 2,683,565bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 2,334,998bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Non-Graded, Recorded Investment 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Commercial Real Estate [Member] | Potential Problem [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 26,028bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		 39,505bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		    
Commercial Real Estate [Member] | Nonaccrual [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 18,557bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 40,850bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Non-Graded, Recorded Investment 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Residential construction and land development [Member]        
Recorded Investment [Abstract]        
Total 143,591us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember		 206,258us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember		    
Residential construction and land development [Member] | Performing [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 127,437bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 173,488bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Non-Graded, Recorded Investment 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Residential construction and land development [Member] | Potential Problem [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 10,855bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		 15,393bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		    
Residential construction and land development [Member] | Nonaccrual [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 5,299bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 17,377bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Non-Graded, Recorded Investment 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Retail [Member]        
Recorded Investment [Abstract]        
Total 666,889us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_RetailMember		 586,047us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_RetailMember		    
Retail [Member] | Performing [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 662,335bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_RetailMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 579,506bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_RetailMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Non-Graded, Recorded Investment 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_RetailMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_RetailMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Retail [Member] | Potential Problem [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 628bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_RetailMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		 1,684bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_RetailMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		    
Retail [Member] | Nonaccrual [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 3,926bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_RetailMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 4,857bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_RetailMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Non-Graded, Recorded Investment 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_RetailMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_RetailMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Office [Member]        
Recorded Investment [Abstract]        
Total 415,544us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_OfficeMember		 411,499us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_OfficeMember		    
Office [Member] | Performing [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 411,548bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_OfficeMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 403,951bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_OfficeMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Non-Graded, Recorded Investment 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_OfficeMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_OfficeMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Office [Member] | Potential Problem [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 576bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_OfficeMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		 1,157bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_OfficeMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		    
Office [Member] | Nonaccrual [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 3,420bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_OfficeMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 6,391bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_OfficeMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Non-Graded, Recorded Investment 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_OfficeMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_OfficeMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Multifamily [Member]        
Recorded Investment [Abstract]        
Total 704,298us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_MultifamilyMember		 576,502us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_MultifamilyMember		    
Multifamily [Member] | Performing [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 691,053bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_MultifamilyMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 562,800bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_MultifamilyMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Non-Graded, Recorded Investment 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_MultifamilyMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_MultifamilyMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Multifamily [Member] | Potential Problem [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 13,245bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_MultifamilyMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		 13,695bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_MultifamilyMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		    
Multifamily [Member] | Nonaccrual [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 0bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_MultifamilyMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 7bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_MultifamilyMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Non-Graded, Recorded Investment 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_MultifamilyMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_MultifamilyMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Industrial [Member]        
Recorded Investment [Abstract]        
Total 428,817us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_IndustrialMember		 243,877us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_IndustrialMember		    
Industrial [Member] | Performing [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 428,817bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_IndustrialMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 243,625bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_IndustrialMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Non-Graded, Recorded Investment 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_IndustrialMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_IndustrialMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Industrial [Member] | Potential Problem [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 0bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_IndustrialMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		 0bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_IndustrialMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		    
Industrial [Member] | Nonaccrual [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 0bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_IndustrialMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 252bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_IndustrialMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Non-Graded, Recorded Investment 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_IndustrialMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_IndustrialMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Other commercial real estate [Member]        
Recorded Investment [Abstract]        
Total 369,011us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_OtherCommercialRealEstateMember		 391,170us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_OtherCommercialRealEstateMember		    
Other commercial real estate [Member] | Performing [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 362,375bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_OtherCommercialRealEstateMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 371,628bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_OtherCommercialRealEstateMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Non-Graded, Recorded Investment 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_OtherCommercialRealEstateMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_OtherCommercialRealEstateMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Other commercial real estate [Member] | Potential Problem [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 724bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_OtherCommercialRealEstateMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		 7,576bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_OtherCommercialRealEstateMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		    
Other commercial real estate [Member] | Nonaccrual [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 5,912bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_OtherCommercialRealEstateMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 11,966bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_OtherCommercialRealEstateMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Non-Graded, Recorded Investment 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_OtherCommercialRealEstateMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_OtherCommercialRealEstateMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Residential Mortgage [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 192,303bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember		 220,635bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember		    
Non-Graded, Recorded Investment 1,757,209bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember		 1,831,391bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember		    
Total 1,949,512us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember		 2,052,026us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember		    
Related Allowance [Abstract]        
Internally Risk Graded, Related Allowance 2,996bokf_InternallyRiskGradedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember		 5,481bokf_InternallyRiskGradedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember		    
Non-Graded, Related Allowance 20,462bokf_NonGradedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember		 23,984bokf_NonGradedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember		    
Total, Related Allowance 23,458us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember		 29,465us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember		    
Residential Mortgage [Member] | Performing [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 187,520bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 210,142bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Non-Graded, Recorded Investment 1,712,098bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 1,796,281bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Residential Mortgage [Member] | Potential Problem [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 1,773bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		 3,283bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		    
Residential Mortgage [Member] | Nonaccrual [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 3,010bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 7,210bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Non-Graded, Recorded Investment 45,111bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 35,110bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialMortgageMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Permanent mortgage [Member]        
Recorded Investment [Abstract]        
Total 969,951us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_PermanentResidentialMortgageMember		 1,062,744us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_PermanentResidentialMortgageMember		    
Permanent mortgage [Member] | Performing [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 187,520bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_PermanentResidentialMortgageMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 210,142bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_PermanentResidentialMortgageMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Non-Graded, Recorded Investment 745,813bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_PermanentResidentialMortgageMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 815,040bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_PermanentResidentialMortgageMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Permanent mortgage [Member] | Potential Problem [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 1,773bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_PermanentResidentialMortgageMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		 3,283bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_PermanentResidentialMortgageMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		    
Permanent mortgage [Member] | Nonaccrual [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 3,010bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_PermanentResidentialMortgageMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 7,210bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_PermanentResidentialMortgageMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Non-Graded, Recorded Investment 31,835bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_PermanentResidentialMortgageMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 27,069bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_PermanentResidentialMortgageMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Permanent mortgages guaranteed by U.S. government agencies [Member]        
Recorded Investment [Abstract]        
Total 205,950us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_PermanentMortgagesGuaranteedByUsGovernmentAgenciesMember		 181,598us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_PermanentMortgagesGuaranteedByUsGovernmentAgenciesMember		    
Permanent mortgages guaranteed by U.S. government agencies [Member] | Performing [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 0bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_PermanentMortgagesGuaranteedByUsGovernmentAgenciesMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 0bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_PermanentMortgagesGuaranteedByUsGovernmentAgenciesMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Non-Graded, Recorded Investment 202,238bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_PermanentMortgagesGuaranteedByUsGovernmentAgenciesMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 180,821bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_PermanentMortgagesGuaranteedByUsGovernmentAgenciesMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Permanent mortgages guaranteed by U.S. government agencies [Member] | Potential Problem [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 0bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_PermanentMortgagesGuaranteedByUsGovernmentAgenciesMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		 0bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_PermanentMortgagesGuaranteedByUsGovernmentAgenciesMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		    
Permanent mortgages guaranteed by U.S. government agencies [Member] | Nonaccrual [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 0bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_PermanentMortgagesGuaranteedByUsGovernmentAgenciesMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 0bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_PermanentMortgagesGuaranteedByUsGovernmentAgenciesMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Non-Graded, Recorded Investment 3,712bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_PermanentMortgagesGuaranteedByUsGovernmentAgenciesMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 777bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_PermanentMortgagesGuaranteedByUsGovernmentAgenciesMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Home equity        
Recorded Investment [Abstract]        
Total 773,611us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember		 807,684us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember		    
Home equity | Performing [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 0bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 0bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Non-Graded, Recorded Investment 764,047bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 800,420bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Home equity | Potential Problem [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 0bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		 0bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		    
Home equity | Nonaccrual [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 0bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 0bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Non-Graded, Recorded Investment 9,564bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 7,264bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Consumer [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 343,227bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember		 265,533bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember		    
Non-Graded, Recorded Investment 91,478bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember		 116,131bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember		    
Total 434,705us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember		 381,664us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember		    
Related Allowance [Abstract]        
Internally Risk Graded, Related Allowance 1,506bokf_InternallyRiskGradedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember		 2,657bokf_InternallyRiskGradedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember		    
Non-Graded, Related Allowance 2,727bokf_NonGradedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember		 4,308bokf_NonGradedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember		    
Total, Related Allowance 4,233us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember		 6,965us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember		    
Consumer [Member] | Performing [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 343,041bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 264,536bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Non-Graded, Recorded Investment 91,079bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 115,114bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		    
Consumer [Member] | Potential Problem [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 19bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		 795bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_PotentialProblemFinancingReceivableMember		    
Consumer [Member] | Nonaccrual [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 167bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 202bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Non-Graded, Recorded Investment 399bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		 1,017bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= bokf_NonaccrualFinancingReceivableMember		    
Specific Allowance [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 12,336,710bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_SpecificAllowanceMember		 10,789,740bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_SpecificAllowanceMember		    
Non-Graded, Recorded Investment 1,871,327bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_SpecificAllowanceMember		 2,002,524bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_SpecificAllowanceMember		    
Total 14,208,037us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_SpecificAllowanceMember		 12,792,264us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_SpecificAllowanceMember		    
Related Allowance [Abstract]        
Internally Risk Graded, Related Allowance 137,032bokf_InternallyRiskGradedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_SpecificAllowanceMember		 127,961bokf_InternallyRiskGradedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_SpecificAllowanceMember		    
Non-Graded, Related Allowance 23,979bokf_NonGradedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_SpecificAllowanceMember		 29,222bokf_NonGradedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_SpecificAllowanceMember		    
Total, Related Allowance 161,011us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_SpecificAllowanceMember		 157,183us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_SpecificAllowanceMember		    
Nonspecific allowance [Member]        
Recorded Investment [Abstract]        
Internally Risk Graded, Recorded Investment 0bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_UnallocatedFinancingReceivablesMember		 0bokf_InternallyRiskGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_UnallocatedFinancingReceivablesMember		    
Non-Graded, Recorded Investment 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_UnallocatedFinancingReceivablesMember		 0bokf_NonGradedRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_UnallocatedFinancingReceivablesMember		    
Total 0us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_UnallocatedFinancingReceivablesMember		 0us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_UnallocatedFinancingReceivablesMember		    
Related Allowance [Abstract]        
Internally Risk Graded, Related Allowance 0bokf_InternallyRiskGradedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_UnallocatedFinancingReceivablesMember		 0bokf_InternallyRiskGradedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_UnallocatedFinancingReceivablesMember		    
Non-Graded, Related Allowance 0bokf_NonGradedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_UnallocatedFinancingReceivablesMember		 0bokf_NonGradedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_UnallocatedFinancingReceivablesMember		    
Total, Related Allowance $ 28,045us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_UnallocatedFinancingReceivablesMember		 $ 28,213us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_UnallocatedFinancingReceivablesMember		 $ 44,187us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_UnallocatedFinancingReceivablesMember		 $ 46,350us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_UnallocatedFinancingReceivablesMember