Trading Securities [Abstract] Schedule of Trading Securities [Table] Trading Securities [Table] Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Domain] Major Types of Debt and Equity Securities [Domain] U.S. government agency debentures US Treasury and Government [Member] U.S. government agency residential mortgage-backed securities Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] Municipal and other tax-exempt securities US States and Political Subdivisions Debt Securities [Member] Asset-backed securities Asset-backed Securities, Securitized Loans and Receivables [Member] Other trading securities Other Trading Securities [Member] Other debt or equity trading securities Schedule of Trading Securities [Line Items] Schedule of Trading Securities and Other Trading Assets [Line Items] Trading Securities, Fair Value Trading Securities Trading Securities, Net Unrealized Gain (Loss) Trading Securities, Net Unrealized Gains (Losses) Represents the unrealized holding gain or loss included in the fair value of trading securities as of the balance sheet. Commitments and Contingencies Disclosure [Abstract] Schedule of Variable Interest Entities [Table Text Block] Schedule of Variable Interest Entities [Table Text Block] Revenue from Contract with Customer [Abstract] Fees and Commissions Revenue [Text Block] Revenue from Contract with Customer [Text Block] Subsequent Events [Abstract] Subsequent Events Subsequent Events [Text Block] Income Statement [Abstract] Interest revenue [Abstract] Interest Income (Expense), Net [Abstract] Loans Interest and Fee Income, Loans and Leases Held-in-portfolio Residential mortgage loans held for sale Interest and Fee Income, Loans Held-for-sale, Mortgages Trading securities Interest and Dividend Income, Securities, Operating, Trading or Measured at Fair Value Investment securities Interest Income, Securities, Operating, Held-to-maturity Available for sale securities Interest and Dividend Income, Securities, Operating, Available-for-sale Fair value option securities Interest revenue on fair value option securities Interest income from fair value option securities that the Company has elected to carry at fair value and separately identify in the Consolidated Balance Sheets with changes in the fair value recognized in earnings as they occur. Restricted equity securities Other Interest and Dividend Income Interest-bearing cash and cash equivalents Interest income, Interest-bearing cash and cash equivalents Interest earned from money market and other interest-bearing accounts held with domestic financial institutions, from excess federal funds sold to another commercial bank requiring such for its legal reserve requirements and from securities purchased under agreements to resell. Total interest revenue Interest and Dividend Income, Operating Interest expense [Abstract] Interest Expense [Abstract] Deposits Interest Expense, Deposits Borrowed funds Interest Expense, Short-term Borrowings Subordinated debentures Interest Expense, Subordinated Notes and Debentures Total interest expense Interest Expense Net interest revenue Interest Income (Expense), Net Provision for credit losses Provision for Loan, Lease, and Other Losses Net interest revenue after provision for credit losses Interest Income (Expense), after Provision for Loan Loss Other operating revenue [Abstract] Other Nonoperating Income (Expense) [Abstract] Brokerage and trading revenue Investment Banking, Advisory, Brokerage, and Underwriting Fees and Commissions Transaction card revenue Transaction card revenue Income earned from the company's EFT network, check card services and merchant fees. Fiduciary and asset management revenue Fees and Commissions, Fiduciary and Trust Activities Deposit service charges and fees Fees and Commissions, Depositor Accounts Mortgage banking revenue Mortgage banking revenue Noninterest income derived from the sale and changes in fair value of residential mortgage loans held for sale and fees for servicing of residential mortgage loans held by third parties. Also includes changes in the fair value of residential mortgage loan commitments and forward sales commitments considered to be derivative instruments. Other revenue Revenue, Other Financial Services Total fees and commissions Total fees and commissions Total fees and commissions earned from providing services such as maintaining: depositor accounts; fiduciary and trust; brokerage and underwriting; mortgage; transaction cards; and other revenue such as bank owned life insurance. Other gains (losses), net Gain (Loss) on Disposition of Assets Loss on derivatives, net Gain (Loss) from Price Risk Management Activity Loss on fair value option securities, net Gain on fair value option securities, net Gain (loss) included in earning for the period related fair value option securities primarily held as an economic hedge of the changes in the fair value of mortgage servicing rights. Change in fair value of mortgage servicing rights Mortgage Servicing Rights (MSR) Impairment (Recovery) Gain (loss) on available for sale securities, net Available-for-sale Securities, Gross Realized Gain (Loss), Excluding Other than Temporary Impairments Total other operating revenue Noninterest Income Other operating expense [Abstract] Noninterest Expense [Abstract] Personnel Labor and Related Expense Business promotion Marketing and Advertising Expense Professional fees and services Professional Fees Net occupancy and equipment Occupancy, Net Insurance Federal Deposit Insurance Corporation Premium Expense Data processing and communications Communications and Information Technology Printing, postage and supplies Supplies and Postage Expense Net losses and operating expenses of repossessed assets Gains (Losses) on Sales of Other Real Estate Amortization of intangible assets Amortization of Intangible Assets Mortgage banking costs Mortgage banking costs Expense related to mortgage banking activities including amortization of capitalized mortgage servicing rights, provision for losses on mortgage loans sold with recourse and other mortgage banking expenses. Other expense Other Noninterest Expense Total other operating expense Noninterest Expense Net income before taxes Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest Federal and state income taxes Income Tax Expense (Benefit) Net income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Net income (loss) attributable to non-controlling interests Net Income (Loss) Attributable to Noncontrolling Interest Net income attributable to BOK Financial Corporation shareholders Net Income (Loss) Attributable to Parent Earnings per share: [Abstract] Earnings Per Share [Abstract] Basic Earnings Per Share, Basic Diluted Earnings Per Share, Diluted Average shares used in computation: [Abstract] Weighted Average Number of Shares Outstanding, Basic [Abstract] Basic Weighted Average Number of Shares Outstanding, Basic Diluted Weighted Average Number of Shares Outstanding, Diluted Dividends declared per share Common Stock, Dividends, Per Share, Declared Disaggregation of Fees and Commissions Revenue [Table Text Block] Disaggregation of Revenue [Table Text Block] Loans Receivable, Net [Abstract] Schedule of Loans by Portfolio Segment [Table Text Block] Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Rollforward of Allowance For Loan Losses And Accrual for Off-Balance Sheet Credit Losses [Table Text Block] Allowance for Credit Losses on Financing Receivables [Table Text Block] Schedule of Allowance for Loan Losses and Recorded Investment by Portfolio Segment for Risk Graded and Non-Risk Graded Loans [Table Text Block] Schedule of Allowance for Loan Losses and Recorded Investment by Portfolio Segment for Risk Graded and Non-Risk Graded Loans [Table Text Block] [Table Text Block] for Schedule of Allowance for Loan Losses and Recorded Investment by Portfolio Segment for Risk Graded and Non-Risk Graded Loans [Table] Schedule of Credit Quality Indicators [Table Text Block] Financing Receivable Credit Quality Indicators [Table Text Block] Summary of Impaired Loans [Table Text Block] Impaired Financing Receivables [Table Text Block] Summary of Loans by Aging Status [Table Text Block] Past Due Financing Receivables [Table Text Block] Schedule of Impaired Loans [Table] Schedule of Impaired Financing Receivable [Table] Financing Receivable Portfolio Segment [Axis] Financing Receivable Portfolio Segment [Axis] Financing Receivable Portfolio Segment [Domain] Financing Receivable Portfolio Segment [Domain] Commercial Commercial Portfolio Segment [Member] Commercial real estate Commercial Real Estate Portfolio Segment [Member] Residential mortgage Residential Portfolio Segment [Member] Personal Consumer Portfolio Segment [Member] Class of Financing Receivable [Axis] Class of Financing Receivable, Type [Axis] Class of Financing Receivable [Domain] Class of Financing Receivable, Type [Domain] Energy [Member] Energy [Member] Class of financing receivables related to energy industry Services [Member] Services [Member] Class of financing receivables related to services industry Wholesale/retail [Member] Wholesale and retail [Member] Class of financing receivables related to wholesale/retail industry. Manufacturing [Member] Manufacturing [Member] Class of financing receivables related to manufacturing industry. Healthcare [Member] Healthcare [Member] Class of financing receivables related to healthcare industry. Other commercial and industrial [Member] Other Commercial and Industrial [Member] Class of financing receivables related to other commercial and industrial industry. Residential construction and land development [Member] Residential construction and land development [Member] Residential construction and land development [Member] Retail [Member] Retail [Member] Class of financing receivables for which repayment will come from the sale or operation of retail facilities. Office [Member] Office [Member] Class of financing receivables related for which repayment will come from the sale or rental of office space. Multifamily [Member] Multifamily [Member] Industrial [Member] Industrial [Member] Class of financing receivables for which repayment will come from the sale or rental of industrial facilities. Other commercial real estate [Member] Other Commercial Real Estate [Member] Class of financing receivables for which repyament is expected from the sale or rental of other commercial real estate properties. Permanent mortgage [Member] Permanent Residential Mortgage [Member] Class of financing receivables related to mortgages of permanent residences. Permanent mortgages guaranteed by US government agencies [Member] Permanent Mortgages Guaranteed by US Government Agencies [Member] Class of financing receivables related to mortages for permanent residences guaranteed by U.S. government agencies. Home equity [Member] Home Equity Line of Credit [Member] Financing Receivable, Impaired [Line Items] Financing Receivable, Impaired [Line Items] Impaired loans [Abstract] Loan and Lease Receivables, Impaired [Abstract] Impaired loans, unpaid principal balance Impaired Financing Receivable, Unpaid Principal Balance Impaired loans, recorded investment, total Impaired Financing Receivable, Recorded Investment Impaired loans, recorded investment with no related allowance Impaired Financing Receivable, with No Related Allowance, Recorded Investment Impaired loans, recorded investment with related allowance Impaired Financing Receivable, with Related Allowance, Recorded Investment Impaired loans, related allowance Impaired Financing Receivable, Related Allowance Impaired loans, average recorded investment Impaired Financing Receivable, Average Recorded Investment Impaired loans, interest income recognized Impaired Financing Receivable, Interest Income, Accrual Method Derivative Instrument Detail [Abstract] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Hedging Designation [Axis] Hedging Designation [Axis] Hedging Designation [Domain] Hedging Designation [Domain] Not Designated as Hedging Instrument [Member] Not Designated as Hedging Instrument [Member] Derivative Instrument [Axis] Derivative Instrument [Axis] Derivative Contract Type [Domain] Derivative Contract [Domain] To-be-announced residential mortgage-backed securities TBA Residential Mortgage-Backed Securities [Member] To-be-announed residential mortgage-backed securities [Member] Interest rate swaps Interest Rate Swap [Member] Energy contracts Energy Related Derivative [Member] Agricultural contracts Agricultural Contracts [Member] Trading in a derivative instrument whose primary underlying risk is tied to agricultural commodity prices. Foreign exchange contracts Foreign Exchange Contract [Member] Equity option contracts Equity Swap [Member] Total customer risk management programs Customer Risk Management Programs [Member] Represents total derivative contracts in customer risk management programs. Internal risk management programs Internal Risk Management Programs [Member] Represents program to manage interest rate sensitivity, as part of its economic hedge of the changes in the fair value of mortgage servicing rights and as an economic hedge of trading securities. Derivatives, Fair Value [Line Items] Derivatives, Fair Value [Line Items] Notional Amount of Derivatives [Abstract] Notional Disclosures [Abstract] Derivative Assets, Notional Derivative Asset, Notional Amount Derivative Liabilities, Notional Derivative Liability, Notional Amount Derivative Assets, Fair Value, Net [Abstract] Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract] Derivative Assets, Gross Fair Value Derivative Asset, Fair Value, Gross Asset Derivative Assets, Netting Adjustments Derivative Asset, Netting Adjustments Represents amount of gross derivative asset positions offset by gross derivate liability due to enforceable master netting or similar agreements. Derivative Assets, Net Fair Value Before Cash Collateral Derivative Assets, Net Fair Value Before Cash Collateral Represents net derivative assets before offsetting the obligation to return cash collateral under a master netting or similar arrangement. Derivative Assets, Cash Collateral Derivative Asset, Collateral, Obligation to Return Cash, Offset Derviative contracts, net of cash collateral, Assets, Fair value Derivative Asset Derivative Liabilities, Fair Value, Net [Abstract] Derivative Liability, Fair Value, Amount Not Offset Against Collateral [Abstract] Derivative Liabilities, Gross Fair Value Derivative Liability, Fair Value, Gross Liability Derivative Liabilities, Netting Adjustments Derivative Liability, Netting Adjustments Represents amount of gross derivative liability positions offset by gross derivative asset positions due to enforceable master netting or similar arrangements. Derivative Liabilities, Net Fair Value Before Cash Collateral Derivative Liability, Net Fair Value Before Cash Collateral Represents net derivative liability before consideration of right to reclasim cash collateral under master netting or similar arrangements. Derivative Liabilities, Cash Collateral Derivative Liability, Collateral, Right to Reclaim Cash, Offset Derivative Liabilities, Fair Value, Net of Cash Collateral Derivative Liability Fair Value Disclosures [Abstract] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Fair Value, Measurements, Recurring [Member] Fair Value, Measurements, Recurring [Member] Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Fair Value, Inputs, Level 3 [Member] Fair Value, Inputs, Level 3 [Member] Asset Class [Axis] Asset Class [Axis] Fair Value by Asset Class [Domain] Asset Class [Domain] Available-for-sale securities [Member] Available-for-sale Securities [Member] Residential mortgage loans held for sale [Member] Residential Mortgage Loans Held for Sale [Member] Represents financial statement line item Residential Mortgage Loans Held for Sale Other debt securities Other Debt Obligations [Member] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Mortgage banking revenue [Member] Mortgage banking revenue [Member] Represents Mortgage banking revenue income statement line item. Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Balance, beginning of period Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value Transfer to Level 3 from Level 2 Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3 Purchases Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases Proceeds from sales Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales Redemptions and distributions Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements Gain (loss) recognized in earnings Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings Other comprehensive income (loss) Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss) Balance, end of period Available-for-sale Securities [Abstract] Schedule of Available-for-sale Securities [Table] Schedule of Available-for-sale Securities [Table] Fixed Maturity Securities [Member] Fixed Income Securities [Member] U.S. Treasury US Treasury Securities [Member] Commercial mortgage-backed securities guaranteed by U.S. government agencies Commercial Mortgage Backed Securities [Member] Residential Mortgage Backed Securities [Member] Residential Mortgage Backed Securities [Member] Privately issued residential mortgage-backed securities Mortgage-backed Securities, Issued by Private Enterprises [Member] Perpetual preferred stock Preferred Stock [Member] Equity securities and mutual funds Equity Securities And Mutual Funds [Member] This category includes information about ownership interests or the right to acquire ownership interests in corporations and mutual funds. Investment Issuer [Axis] Investment Issuer [Axis] Investment Issuer [Domain] Investment Issuer [Domain] Federal National Mortgage Association Certificates and Obligations (FNMA) [Member] Federal National Mortgage Association Certificates and Obligations (FNMA) [Member] Federal Home Loan Mortgage Corporation Certificates and Obligations (FHLMC) [Member] Federal Home Loan Mortgage Corporation Certificates and Obligations (FHLMC) [Member] Government National Mortgage Association Certificates and Obligations (GNMA) [Member] Government National Mortgage Association Certificates and Obligations (GNMA) [Member] Schedule of Available-for-sale Securities [Line Items] Schedule of Available-for-sale Securities [Line Items] Available-for-sale Securities, Amortized Cost Available-for-sale Securities, Amortized Cost Basis Available-for-sale Securities, Fair Value Available-for-sale Securities Available-for-sale Securities, Gross Unrealized Gain Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax Available-for-sale Securities, Gross Unrealized Loss Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax Available-for-Sale Securities, Other Than Temporary Impairments Available-for-Sale Securities, Other Than Temporary Impairments The unrealized loss as of the balance sheet date that remains in Accumulated Other Comprehensive Income subsequent to an other-than-temporary impairment loss being recognized in earnings. Available-for-sale Securities, Debt Maturities [Abstract] Available-for-sale Securities, Debt Maturities [Abstract] Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Rolling Maturity [Abstract] Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Rolling Maturity [Abstract] Available-for-sale Securities, Debt Maturities, Less than One Year, Amortized Cost Basis Available-for-sale Securities, Debt Maturities, Next Rolling Twelve Months, Amortized Cost Basis Available-for-sale Securities, Debt Maturities, One to Five Years, Amortized Cost Basis Available-for-sale Securities, Debt Maturities, Rolling Year Two Through Five, Amortized Cost Basis Available-for-sale Securities, Debt Maturities, Six To Ten Years, Amortized Cost Basis Available-for-sale Securities, Debt Maturities, Rolling Year Six Through Ten, Amortized Cost Basis Available-for-sale Securities, Debt Maturities, Over Ten Years, Amortized Cost Basis Available-for-sale Securities, Debt Maturities, Rolling after Year Ten, Amortized Cost Basis Available-for-sale Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis Available-for-sale Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Amortized Cost Basis Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Amortized Cost Basis Available-for-sale Securities, Debt Maturities, Amortized Cost Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract] Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract] Available-for-sale Securities, Debt Maturities, Less than One Year, Fair Value Available-for-sale Securities, Debt Maturities, Next Rolling Twelve Months, Fair Value Available-for-sale Securities, Debt Maturities, One to Five Years, Fair Value Available-for-sale Securities, Debt Maturities, Rolling Year Two Through Five, Fair Value Available-for-sale Securities, Debt Maturities, Six to Ten Years, Fair Value Available-for-sale Securities, Debt Maturities, Rolling Year Six Through Ten, Fair Value Available-for-sale Securities, Debt Maturities, Over Ten Years, Fair Value Available-for-sale Securities, Debt Maturities, Rolling after Year Ten, Fair Value Available-for-sale Securities, Debt Maturities, Single Maturity Date Available-for-sale Securities, Debt Maturities, Single Maturity Date Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Fair Value Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Fair Value Available-for-sale Securities, Debt Maturities, Fair Value Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract] Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract] -- None. No documentation exists for this element. -- Available-for-sale Securities, Debt Maturities, Less than One Year, Nominal Yield Available-for-sale Securities, Debt Maturities, Next Rolling Twelve Months, Nominal Yield Nominal yield of available-for-sale securities maturing in the next rolling twelve months following the balance sheet presented. Available-for-sale Securities, Debt Maturities, One to Five Years, Nominal Yield Available-for-sale Securities, Debt Maturities, Rolling Year Two Through Five, Nominal Yield Represents the nominal yield of available-for-sale securities maturing in the second rolling twelve months through the fifth rolling twelve months following the balance sheet date presented. Available-for-sale Securities, Debt Maturities, Six To Ten Years, Nominal Yield Available-for-sale Securities, Debt Maturities, Rolling Year Six Through Ten, Nominal Yield Represents the nominal yield of available-for-sale securities maturing in the sixth rolling twelve months through the tenth rolling twelve months following the balance sheet presented Available-for-sale Securities, Debt Maturities, Over Ten Years, Nominal Yield Available-for-sale Securities, Debt Maturities, Rolling after Year Ten, Nominal Yield Represents the nominal yield of available-for-sale securities maturing after tenth rolling twevle months following the balance sheet presented Available-for-sale Securities, Debt Maturities, Nominal Yield Available-for-sale Securities, Debt Maturities, Nominal Yield Represents the nominal yield of available-for sale securities as of the balance sheet date. Available-for-sale Securities, Debt Maturities, Weighted Average Maturity Available-for-sale Securities, Debt Maturities, Weighted Average Maturity Represents the the contractual weighted average maturity (weighted by amount of the security) for this portion of the available-for-sale securities portfolio. Available-for-sale Securities, Debt Maturities, Effective tax rate for nominal yield calculation Available-for-sale Securities, Debt Maturities, Effective tax rate for nominal yield calculation Effective tax rate for nominal yield calculation for available for sale securities. Available-for-sale Securities, Debt Maturities, Average Expected Life of Mortgage-backed Securities Available-for-sale Securities, Debt Maturities, Average Expected Life of Mortgage-backed Securities The calculated weighted-average expected life of mortgage-backed securities based on prepayment assumptions as of the balance sheet date. Available-for-sale Securities, Debt Maturities, Number of days for interest rates to reset Available-for-sale Securities, Debt Maturities, Number of days for interest rates to reset Number of days for interest rates to reset on variable rate municipal or other debt securities. Available-for-sale Securities, Gross Realized Gain (Loss), Disclosures [Abstract] Available-for-sale Securities, Gross Realized Gain (Loss), Disclosures [Abstract] Available-for-sale Securities, Proceeds Available-for-sale Securities, Gross Realized Gains (Losses), Sale Proceeds Available-for-sale Securities, Gross realized gains Available-for-sale Securities, Gross Realized Gains Available-for-sale Securities, Gross realized losses Available-for-sale Securities, Gross Realized Losses Available-for-sale Securities, Related federal and state income tax expense Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax Available-for-sale Securities, Pledged as Collateral [Abstract] Available-for-sale Securities, Pledged as Collateral [Abstract] Available-for-sale Securities, Pledged as Collateral [Abstract] Available-for-sale Securities, Pledged As Collateral, Amortized cost Available For Sale Securities Pledged As Collateral Amortized cost Amortized cost of available for sale securities pledged as collateral for repurchase agreements, public and trust funds on deposit and for other purposes, as required by law for which the secured parties do not have the right to sell or re-pledge these securities. Available-for-sale Securities, Pledged As Collateral, Fair value Available-for-sale Securities Pledged as Collateral Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract] Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract] Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract] Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract] Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract] Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract] Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract] Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss [Abstract] Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss Accounting Policies [Abstract] Basis of Accounting, Policy [Policy Text Block] Basis of Accounting, Policy [Policy Text Block] Principles of Consolidation [Policy Text Block] Consolidation, Policy [Policy Text Block] Reclassification, Policy [Policy Text Block] Reclassification, Policy [Policy Text Block] Newly Adopted and Pending Accounting Policies [Policy Text Block] New Accounting Pronouncements, Policy [Policy Text Block] Derivatives, Policy [Policy Text Block] Derivatives, Policy [Policy Text Block] Loans and Allowances for Credit Losses, Loans [Policy Text Block] Policy Loans Receivable, Policy [Policy Text Block] Loans and Allowances for Credit Losses, Allowances for Credit Losses [Policy Text Block] Loans and Leases Receivable, Allowance for Loan Losses Policy [Policy Text Block] Revenue Recognition, Policy [Policy Text Block] Revenue Recognition, Policy [Policy Text Block] Income Tax Disclosure [Abstract] Effective Income Tax Rate Reconciliation, Amount [Abstract] Effective Income Tax Rate Reconciliation, Amount [Abstract] Federal statutory tax Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount Tax exempt revenue Effective Income Tax Rate Reconciliation, Tax Exempt Income, Amount Effect of state income taxes, net of federal benefit Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount Utilization of tax credits, net of proportional amortization of low-income housing limited partnership investments Effective Income Tax Rate Reconciliation, Tax Credit, Other, Amount Share-based compensation Income Tax Reconciliation, Share-based Compensation Represents the excess tax deficiency (benefit) on share-based payment awards recognized in income tax expense unrelated to pre-tax net income. Adjustment to provisional amounts related to tax reform Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount Other, net Effective Income Tax Rate Reconciliation, Other Adjustments, Amount Total income tax expense Effective Income Tax Rate Reconciliation, Percent [Abstract] Effective Income Tax Rate Reconciliation, Percent [Abstract] Federal statutory tax (in hundredths) Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Tax exempt revenue (in hundredths) Effective Income Tax Rate Reconciliation, Tax Exempt Income, Percent Effect of state income taxes, net of federal benefit (in hundredths) Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent Utilization of tax credits, net of proportional amortization of low-income housing limited partnership investments (in hundredths) Effective Income Tax Rate Reconciliation, Tax Credit, Other, Percent Share-based compensation (in hundredths) Income Tax Reconciliation, Share-based Compensation, Percent Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) from excess tax deficiency (benefit) on share-based payment awards recognized in income tax expense unrelated to pre-tax net income. Adjustment to provisional amounts related to tax reform (in hundredths) Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent Other, net (in hundredths) Effective Income Tax Rate Reconciliation, Other Adjustments, Percent Total (in hundredths) Effective Income Tax Rate Reconciliation, Percent Tax Cuts and Jobs Act, Revaluation of Net Deferred Tax Assets Related to Temporary Differences in Accumulated Comprehensive Income Tax Cuts and Jobs Act, Revaluation of Net Deferred Tax Assets Related to Temporary Differences in Accumulated Comprehensive Income Represents revaluation of net deferred tax assets related to temporary differences in accumulated comprehensive income due to change in tax rates. Tax Cuts and Jobs Act, Write-off of Deferred Tax Assets Related to Executive Compensation Effective Income Tax Rate Reconciliation, Write-off of Deferred Tax Assets Related to Executive Compensation, Amount Represents the effect of the write-off of deferred tax assets resulting from executive compensation that may no longer be deductible related to the implementation of the 2017 Tax Cut and Jobs Act implementation. Segment Reporting [Abstract] Segments Reporting Information [Table] Reconciliation of Revenue from Segments to Consolidated [Table] Consolidation Items [Axis] Consolidation Items [Axis] Consolidation Items [Domain] Consolidation Items [Domain] Operating Segments [Member] Operating Segments [Member] Funds Management and Other [Member] Corporate, Non-Segment [Member] Segments [Axis] Segments [Axis] Segments [Domain] Segments [Domain] Commercial [Member] Commercial [Member] Business segment-commercial customers. Consumer [Member] Consumer [Member] Business segment-consumer customers. Wealth Management [Member] Wealth Management [Member] Business segment-wealth management consulting customers. Segment Reporting Information [Line Items] Segment Reporting, Revenue Reconciling Item [Line Items] Tax-equivalent net interest revenue from external sources NIR (expense) from external sources Amount of interest revenue, primarily from loans and securities net of interest expense (cost of borrowed funds accounted for as interest) from external sources. Tax-equivalent net interest revenue (expense) from internal sources NIR (expense) from internal sources Amount of interest revenue earned or paid on funds loaned to or borrowed from the funds management unit net of interest expense (cost of borrowed funds accounted for as interest) from internal sources. Net interest revenue after provision for credit losses Other operating revenue Other operating expense Net direct contribution Net direct contribution Represents net direct contribution of segments prior to corporate expense allocations. Gain (loss) on financial instruments, net Gain (Loss) on Financial Instruments, Net Represents gain (loss) on financial instruments, net, used for segment reporting purposes on a summary basis. Includes those gains and losses from derivative contracts, fair value option securities and available for sale securities. Also includes in other-than-temporary impairment losses recognized in earnings. Change in fair value of mortgage servicing rights Segment Reporting, Change in Fair Value of Mortgage Servicing Rights Represents the change in the fair value of mortgage servicing rights used for segment reporting purposes. Loss on repossessed assets, net Gain (Loss) on Sale of Assets and Asset Impairment Charges Corporate expense allocations Corporate Expense Allocations Represent allocation of corporate expenses to segments Net income Net income (loss) attributable to non-controlling interests Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest Net income attributable to BOK Financial Corp. shareholders Average assets Average Assets for Reporting Period Amount of average assets attributed to the reportable segment for the reporting period. Mortgage Banking [Abstract] Schedule of Aging of Mortgage Loans Serviced For Others [Table] Schedule of Aging of Mortgage Loans Serviced For Others [Table] -- None. No documentation exists for this element. -- Loans Insured or Guaranteed by Government Authorities [Axis] Loans Insured or Guaranteed by Government Authorities [Axis] Loans Insured or Guaranteed by Government Authorities [Domain] Loans Insured or Guaranteed by Government Authorities [Domain] FHLMC [Member] Federal Home Loan Mortgage Corporation (FHLMC) Insured Loans [Member] FNMA [Member] Federal National Mortgage Association (FNMA) Insured Loans [Member] GNMA [Member] Government National Mortgage Association (GNMA) Insured Loans [Member] Other [Member] Other Investor Loans [Member] Loans provided by a type of investor not previously identified. Schedule of Aging of Mortgage Loans Serviced For Others [Line Items] Schedule of Aging of Mortgage Loans Serviced For Others [Line Items] -- None. No documentation exists for this element. -- Financing Receivable, Recorded Investment, Aging [Abstract] Financing Receivable, Recorded Investment, Aging [Abstract] Current Loans Serviced For Others current The current portion dollar amount of principal for mortgage loans being serviced for others. 30 to 59 Days Past Due Loans Serviced For Others30 To59 Days Past Due Loans Serviced for Others that are less than 60 days past due but more than 29 days past due. 60 to 89 Days Past Due Loans Serviced For Others60 To89 Days Past Due Loans Serviced for Others that are less than 90 days past due but more than 59 days past due. 90 Days or More Past Due Loans Serviced For Otherst Equal To Greater Than90 Days Past Due Loans Serviced for Others that are equal to or greater than 90 days past due. Total Loans Serviced For Others The dollar amount of principal for mortgage loans being serviced for others. Fair Value Measurements [Text Block] Fair Value Disclosures [Text Block] Held-to-maturity Securities, Unclassified [Abstract] Schedule of Held-to-maturity Securities [Table] Schedule of Held-to-maturity Securities [Table] Other U.S. agency residental mortgage backed securities - Other [Member] Debt securities collateralized by real estate mortgage loans (mortgages), issued by other US Government Sponsored Enterprises. Schedule of Investment (Held-to-Maturity) Securities [Line Items] Schedule of Held-to-maturity Securities [Line Items] Investments Securities, Amortized Cost Held-to-maturity Securities Investment Securities, fair value Held-to-maturity Securities, Fair Value Investment Securities, Gross Unrealized Gain Held-to-maturity Securities, Accumulated Unrecognized Holding Gain Investment Securities, Gross Unrealized Loss Held-to-maturity Securities, Accumulated Unrecognized Holding Loss Investment Securities, Debt Maturities [Abstract] Held-to-maturity Securities, Debt Maturities [Abstract] Investment Securities, Debt Maturities, Net Carrying Value [Abstract] Held-to-maturity Securities, Debt Maturities, Net Carrying Amount [Abstract] Investment Securities, Debt Maturities, Less than One Year, Net Carrying Value Held-to-maturity Securities, Debt Maturities, Next Rolling Twelve Months, Amortized Cost Investment Securities, Debt Maturities, One to Five Years, Net Carrying Value Held-to-maturity Securities, Debt Maturities, Rolling Year Two Through Five, Amortized Cost Investment Securities, Debt Maturities, Six to Ten Years, Net Carrying Value Held-to-maturity Securities, Debt Maturities, Rolling Year Six Through Ten, Amortized Cost Investment Securities, Debt Maturities, Over Ten Years, Net Carrying Value Held-to-maturity Securities, Debt Maturities, Rolling after Ten Years, Amortized Cost Investment Securities, Debt Maturities, Single Maturity Date, Net Carrying Value Held-to-maturity Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis Investment Securities, Debt Maturities, without Single Maturity Date, Net Carrying Value Held-to-maturity Securities, Debt Maturities, without Single Maturity Date, Net Carrying Amount Investments Securities, Debt Maturities, Amortized Cost Investment Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract] Held-to-maturity Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract] Investment Securities, Debt Maturities, Less Than One Year, Fair Value Held-to-maturity Securities, Debt Maturities, Next Rolling Twelve Months, Fair Value Investment Securities, Debt Maturities, One to Five Years, Fair Value Held-to-maturity Securities, Debt Maturities, Rolling Year Two Through Five, Fair Value Investment Securities, Debt Maturities, Six to Ten Years, Fair Value Held-to-maturity Securities, Debt Maturities, Rolling Year Six Through Ten, Fair Value Investment Securities, Debt Maturities, Over Ten Years, Fair Value Held-to-maturity Securities, Debt Maturities, Rolling after Ten Years, Fair Value Investment Securities, Debt Maturities, Single Maturity Date, Fair Value Held-to-maturity Securities, Debt Maturities, Single Maturity Date, Fair Value Investment Securities, Debt Maturities, without Single Maturity Date, Fair Value Held-to-maturity Securities, Debt Maturities, without Single Maturity Date, Fair Value Investment Securities, Debt Maturities, Fair Value Investment Securities, Debt Maturities, Nominal Yield [Abstract] Held-to-maturity Securities, Debt Maturities, Nominal Yield [Abstract] Held-to-maturity Securities, Debt Maturities, Nominal Yield [Abstract] Investment Securities, Debt Maturities, Less Than One Year, Nominal Yield Held-to-maturity Securities, Debt Maturities, Next Rolling Twelve Months, Nominal Yield Nominal yield on the securities maturing in the next rolling twelve months following the latest balance sheet presented, as calculated from its issuance value or purchase price. Investment Securities, Debt Maturities, One to Five Years, Nominal Yield Held-to-maturity Securities, Debt Maturities, Rolling Year Two Through Five, Nominal Yield Nominal yield on the securities maturing in the second rolling twelve months through fifth rolling twelve months following the latest balance sheet presented. as calculated from its issuance value or purchase price. Investment Securities, Debt Maturities, Six to Ten Years, Nominal Yield Held-to-maturity Securities, Debt Maturities, Rolling Year Six Through Ten, Nominal Yield Nominal yield on the securities maturing in sixth through tenth rolling twelve months following the latest balance sheet presented, as calculated from its issuance value or purchase price. Investment Securities, Debt Maturities, Over Ten Years, Nominal Yield Held-to-maturity Securities, Debt Maturities, Rolling after Ten Years, Nominal Yield Nominal yield on the securities maturing after the tenth rolling twelve months following the latest balance sheet presented, as calculated from its issuance value or purchase price. Investment Securities, Debt Maturities, Nominal Yield Held-to-maturity Securities, Debt Maturities, Nominal Yield Total nominal yield for Held-to-maturity Securities over varying maturity dates Investment Securities, Debt Maturities, Weighted Average Maturity Held-to-maturity Securities, Debt Maturities, Weighted Average Maturity Represents the weighted average maturity (weighted by amount of the security) of all securities in this investment type. Investment Securities,Debt Maturities, Effective tax rate for nominal yield calculation Held-to-Maturity Securities, Debt Maturities, Effective tax rate for nominal yield calculation Effective tax rate for nominal yield calculation for investment (held-to-maturity) securities. Investment Securities, Debt Maturities, Average Expected Life of Mortgage-backed Securities Held-to-maturity Securities, Debt Maturities, Average Expected Life of Mortgage-backed Securities The calculated weighted-average expected life of mortgage-backed securities held to maturity based on prepayment assumptions as of the balance sheet date. Investment Securities, Pledged as Collateral [Abstract] Held-to-maturity Securities, Pledged as Collateral [Abstract] Held-to-maturity Securities, Pledged as Collateral [Abstract] Investment Securities, Pledged as Collateral, Amortized Cost Held-to-maturity Securities Pledged as Collateral Investment Securities, Pledged as Collateral, Fair Value Held-to-maturity Collateral, Fair Value Represents fair value as of the balance sheet date for held-to-maturity securities pledged as collateral for repurchase agreements, public and trust funds on deposit and for other purposes, as required by law for which the secured party does not have the right to sell or re-pledge. Investment Securities, Continuous Unrealized Loss Position [Abstract] Held-to-maturity Securities, Continuous Unrealized Loss Position [Abstract] Investment Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract] Held-to-maturity Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract] Investment Securities, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions Held-to-maturity, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions Investment Securities, Continuous Unrealized Loss Position, Fair Value [Abstract] Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value [Abstract] Investment Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value Investment Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value Investment Securities, Continuous Unrealized Loss Position, Fair Value Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value Investment Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract] Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Loss [Abstract] Investment Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Investment Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Investment Securities, Continuous Unrealized Loss Position, Accumulated Loss Held-to-maturity Securities, Continuous Unrealized Loss Position, Accumulated Loss Derivative Contracts [Table Text Block] Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block] Derivative Instruments, Gain (Loss) in Statement of Earnings [Table Text Block] Derivative Instruments, Gain (Loss) [Table Text Block] Loans [Text Block] Loans, Notes, Trade and Other Receivables Disclosure [Text Block] Loans and Allowance for Credit Losses [Abstract] Loans and Allowance for Credit Losses [Abstract] Loans, Number of Days Past Due for a Non-Risk Graded Loan to be Placed on Nonaccruing Status Loans, Number of Days Past Due for a Non-Risk Graded Loan to be Placed on Nonaccruing Status Represents the number of days past due a non-risk graded loan has to be in order to be placed on nonaccruing status. Loans, Number of Days After Notification of Chapter 7 Bankruptcy Non-Risk Graded Loan is Placed on Nonaccruing Status Loans, Number of Days After Notification of Chapter 7 Bankruptcy Non-Risk Graded Loan is Placed on Nonaccruing Status The number of days following notification of a borrowers Chapter 7 bankruptcy that a non-risk graded loan is placed on nonaccruing status. Loans and Allowances for Credit Losses, Minimum No of Days After Which Past Due Non-Risk Graded Loans Are Charged Off Minimum No of Days After Which Past Due Non-Risk Graded Loans Are Charged Off Minimum number of days after which past due non-risk graded loans are charged off Loans and Allowances for Credit Losses, Maximum No of Days After Which Past Due Non-Risk Graded Loans Are Charged Off Max No of Days After Which Past Due Non-Risk Graded Loans Are Charged Off Maximum number of days after which past due non-risk graded loans are charged off Loans, Number of Days After Notification of Chapter 7 Bankruptcy Non-Risk Graded Loan is Charged Off Loans, Number of Days After Notification of Chapter 7 Bankruptcy Non-Risk Graded Loan is Charged Off Represents the number of days after notification of Chapter 7 bankruptcy for a non-risk graded loan to be charged off Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Products and Services [Axis] Products and Services [Axis] Products and Services [Domain] Products and Services [Domain] Fees and commissions revenue [Member] Fees and commissions revenue [Member] Fees and commissions revenue [Member] Brokerage and trading revenue [Member] Brokerage and trading revenue [Member] Brokerage and trading revenue [Member] Trading revenue [Member] Gain loss on trading [Member] Gain loss on trading [Member] Customer hedging revenue [Member] Customer hedging revenue [Member] Customer hedging revenue [Member] Retail brokerage revenue [Member] Retail brokerage revenue [Member] Retail brokerage revenue [Member] Investment banking revenue [Member] Investment banking revenue [Member] Investment banking revenue [Member] Transaction card revenue [Member] Transaction card revenue [Member] Transaction card revenue [Member] TransFund EFT network revenue [Member] TransFund EFT network revenue [Member] TransFund EFT network revenue [Member] Merchant services revenue [Member] Merchant services revenue [Member] Merchant services revenue [Member] Fiduciary and asset management revenue [Member] Fiduciary and asset management revenue [Member] Fiduciary and asset management revenue [Member] Personal trust revenue [Member] Personal trust revenue [Member] Personal trust revenue [Member] Corporate trust revenue [Member] Corporate trust revenue [Member] Corporate trust revenue [Member] Institutional trust & retirement plan services revenue [Member] Institutional trust & retirement plan services revenue [Member] Institutional trust & retirement plan services revenue [Member] Investment management services and other [Member] Investment management services and other [Member] Investment management services and other [Member] Deposit service charges and fees [Member] Deposit service charges and fees [Member] Deposit service charges and fees [Member] Commercial account service charge revenue [Member] Commercial account service charge revenue [Member] Commercial account service charge revenue [Member] Overdraft fee revenue [Member] Overdraft fee revenue [Member] Overdraft fee revenue [Member] Check card fee revenue [Member] Check card fee revenue [Member] Check card fee revenue [Member] Automated service charge and other deposit fee revenue [Member] Automated service charge and other deposit fee revenue [Member] Automated service charge and other deposit fee revenue [Member] Mortgage production revenue [Member] Mortgage production revenue [Member] Mortgage production revenue [Member] Mortgage servicing revenue [Member] Mortgage servicing revenue [Member] Mortgage servicing revenue [Member] Other revenue [Member] Other revenue [Member] Other revenue [Member] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Fees and commission revenue not from contracts with customers Fees and commission revenue not from contracts with customers Represents fees and commissions revenue not in the scope of ASC 606, Revenue from Contracts with Customers, related to financial instruments or from contractual rights and obligations within the scope of other applicable accounting guidance. Fees and commissions revenue from contracts with customers Revenue from Contract with Customer, Excluding Assessed Tax Summary of Mortgage Servicing Rights [Abstract] Summary of Mortgage Servicing Rights [Abstract] -- None. No documentation exists for this element. -- Number of residential mortgage loans serviced for others Residential Mortgage Loans Serviced Number Of Loans Indicates the number of mortgage loans being serviced. Outstanding principal balance of residential mortgage loans serviced for others Residential Mortgage Loans Serviced Outstanding Principal Dollar amount of principal outstanding on mortgage loans being serviced. Weighted average interest rate Weighted Average Interest Rate of Loans Serviced for Others Represents the weighted average interest rate of loans servicedf for others as of the balance sheet date. Remaining term (in months) Residential Mortgage Loans Serviced Weighted Average Remaining Term Represents the weighted average remaining term of mortgage loans being serviced fro others. Servicing Asset at Fair Value, Amount [Roll Forward] Servicing Asset at Fair Value, Amount [Roll Forward] Beginning balance Servicing Asset at Fair Value, Amount Additions, net Servicing Asset at Fair Value, Additions Change in fair value due to principal payments Change in fair value due to loan runoff The decrease in fair value as a result of loan runoff. Change in fair value due to market assumption changes Asset at Fair Value, Changes in Fair Value Resulting from Changes in Assumptions Ending balance Servicing Assets at Fair Value, Assumptions Used to Estimate Fair Value [Abstract] Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value [Abstract] Discount rate - risk-free rate plus a market premium (in hundredths) Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Discount Rate Prepayment rate - based upon loan interest rate, original term and loan type, minimum Servicing Assets At Fair Value Assumptions Used To Estimate Fair Value Prepayment Speed Minimum The minimum estimated speed of prepayments of principal on financial assets which may be one of the factors applied in estimating the fair value of servicing assets. Prepayment rate - based upon loan interest rate, original term and loan type, maximum Servicing Assets At Fair Value Assumptions Used To Estimate Fair Value Prepayment Speed Maximum The maximum estimated speed of prepayments of principal on financial assets which may be one of the factors applied in estimating the fair value of servicing assets. Loan servicing costs - annually per loan based upon loan type, performing, minimum (in dollars per loan) Servicing Assets At Fair Value Assumptions Used To Estimate Fair Value Performing Loan Service Cost Minimum The minimum cost to service a performing loan for the period used as a variable in estimating fair value. Loan servicing costs - annually per loan based upon loan type, performing, maximum (in dollars per loan) Servicing Assets At Fair Value Assumptions Used To Estimate Fair Value Performing Loan Service Cost Maximum The maximum cost to service a performing loan for the period used as a variable in estimating fair value. Loan servicing costs - annually per loan based upon loan type, delinquent, minimum (in dollars per loan) Servicing Assets at Fair Value Assumptions Used to Estimate Fair Value Delinquent Loan Service Cost Minimum Servicing Assets at Fair Value Assumptions Used to Estimate Fair Value Delinquent Loan Service Cost Minimum Loan servicing costs - annually per loan based upon loan type, delinquent, maximum (in dollars per loan) Servicing Assets At Fair Value Assumptions Used to Estimate Fair Value Delinquent Loan Svc Cost Maximum Servicing Assets At Fair Value Assumptions Used to Estimate Fair Value Delinquent Loan servicing costs - annually per loan based upon loan type, foreclosure, minimum (in dollars per loan) Servicing Assets at Fair Value Assumptions Used to Estimate Fair Value Foreclosure Loan Service Cost Minimum Servicing Assets at Fair Value Assumptions Used to Estimate Fair Value Foreclosure Loan Service Cost Minimum Loan servicing costs - annually per loan based upon loan type, foreclosure, maximum (in dollars per loan) Servicing Assets At Fair Value Assumptions Used to Estimate Fair Value Foreclosure Loan Service Cost Maximum Servicing Assets At Fair Value Assumptions Used to Estimate Fair Value Foreclosure Loan Service Cost Maximum Escrow earnings rate - indexed to rates paid on deposit accounts with comparable average life (in hundredths) Servicing Assets At Fair Value Assumptions Used To Estimate Fair Value Escrow Earnings Rate The escrow earning rate used to estimate the fair value of servicing assets, based on rates paid on deposit accounts. Primary secondary mortgage rate spread (in basis points) Primary secondary mortgage rate spread Mortgage rate spread between the primary and secondary market. Restricted Equity Securities [Abstract] Restricted Equity Securities [Abstract] Federal Reserve stock Federal Reserve Bank Stock Federal Home Loan Bank stock Federal Home Loan Bank Stock Other Other restricted equity securities Represents other restricted equity securities without readily determinable fair value due to lack of marketability. Total Federal Home Loan Bank Stock and Federal Reserve Bank Stock Statement of Comprehensive Income [Abstract] Other comprehensive income (loss) before income taxes: Other Comprehensive Income (Loss), before Tax [Abstract] Net change in unrealized gain (loss) Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, before Tax Reclassification adjustments included in earnings: Reclassification Adjustments Included in Earnings [Abstract] Reclassification Adjustments Included in Earnings [Abstract] Loss (gain) on available for sale securities, net Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax Other comprehensive income (loss) before income taxes Other Comprehensive Income (Loss), before Tax Federal and state income taxes Other Comprehensive Income (Loss), Tax Other comprehensive income (loss), net of income taxes Other Comprehensive Income (Loss), Net of Tax Comprehensive income Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Comprehensive income (loss) attributable to non-controlling interests Comprehensive income attributable to BOK Financial Corp. shareholders Comprehensive Income (Loss), Net of Tax, Attributable to Parent Organization, Consolidation and Presentation of Financial Statements [Abstract] Interchange fees related to transaction card processing revenue Interchange fees related to transaction card processing revenue Interchange fees related to transaction card processing revenue Increase of reported right of use assets and liabilities Increase of reported right of use assets and liabilities Increase of reported right of use assets and liabilities minimum Increase of reported right of use assets and liabilities maximum Increase of reported right of use assets and liabilities maximum Increase of reported right of use assets and liabilities maximum Stockholders' Equity Note [Abstract] Accumulated Other Comprehensive Income (Loss) [Table Text Block] Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Statement [Table] Statement [Table] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event [Member] Subsequent Event [Member] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Accumulated Net Unrealized Gain (Loss) on Available for Sale Securities [Member] Accumulated Net Investment Gain (Loss) Attributable to Parent [Member] Accumulated Unrealized Gain (Loss) on Employee Benefit Plans [Member] Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Statement [Line Items] Statement [Line Items] Dividends Payable, Date Declared Dividends Payable, Date Declared Dividends declared (in dollars per share) Dividends Payable, Date to be Paid Dividends Payable, Date to be Paid Dividends Payable, Date of Record Dividends Payable, Date of Record Schedule of Accumulated Other Income (Loss) [Abstract] Schedule of Accumulated Other Comprehensive Income [Roll Forward] -- None. No documentation exists for this element. -- Balance, Beginning of Period Accumulated Other Comprehensive Income (Loss), Net of Tax Transition adjustment for unrealized gains and losses on equity securities Cumulative Effect of New Accounting Principle in Period of Adoption Net change in unrealized gain (loss) Other comprehensive income (loss), before income taxes Other comprehensive income (loss), net of income taxes Balance, End of Period Mortgage Banking Activities [Text Block] Mortgage Banking Activities [Text Block] Mortgage Banking Activities [Text Block] Fair Value Measurement, Measured On Non-Recurring Basis, Significant Unobservable Inputs, Quantitative Information [Abstract] Fair Value Measurement, Measured On Non-Recurring Basis, Significant Unobservable Inputs, Quantitative Information [Abstract] Fair Value Inputs, Assets, Quantitative Information [Table] Fair Value Inputs, Assets, Quantitative Information [Table] Measurement Frequency [Axis] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Measurements, Nonrecurring [Member] Impaired Loans [Member] Fair Value, Impaired Loans [Member] Fair Value, Impaired Loans [Member] Real estate and other repossessed assets [Member] Fair Value, Real estate and other repossessed assets [Member] Fair Value, Real estate and other repossessed assets [Member] Fair Value Inputs, Assets, Quantitative Information [Line Items] Fair Value Inputs, Assets, Quantitative Information [Line Items] Carrying Value Assets, Fair Value Disclosure, Nonrecurring Fair Value Measurements, Valuation Techniques Fair Value Measurements, Valuation Techniques Fair Value Measurements, Significant Unobservable Input Fair Value Measurements, Significant Unobservable Input Description of significant unobservable input used in recurring fair value measurement. Fair Value of Impaired Loans as a Percentage of Unpaid Principal Balance [Abstract] Fair Value of Impaired Loans as a Percentage of Unpaid Principal Balance [Abstract] Fair Value of Impaired Loans as a Percentage of Unpaid Principal Balance [Abstract] Fair Value Measurements, Fair Value of Impaired Loans as a Percentage of Unpaid Principal Balance, Minimum Fair Value of Impaired Loans as a Percentage of Unpaid Principal Balance, Minimum Represents the lowest percentage in the range of fair values of impaired loans to the unpaid principal balance. Fair Value Measurements, Fair Value of Impaired Loans as a Percentage of Unpaid Principal Balance, Maximum Fair Value of Impaired Loans as a Percentage of Unpaid Principal Balance, Maximum Represents the highest percentage in the range of fair values of impaired loans to the unpaid principal balance. Fair Value of Impaired Loans as a Percentage of Unpaid Principal Balance, Weighted Average Fair Value of Impaired Loans as a Percentage of Unpaid Principal Balance, Weighted Average Represents the weighted average of the fair values of impaired loans to the unpaid principal balance at the balance sheet date. Fair Value of Real Estate and Other Repossessed Assets as a Percentage of Appraised Value [Abstract] Fair Value of Real Estate and Other Repossessed Assets as a Percentage of Appraised Value [Abstract] Fair Value of Real Estate and Other Repossessed Assets as a Percentage of Appraised Value [Abstract] Fair Value Measurement, Percentage of Appraised Value. Minimum Fair Value Measurement, Percentage of Appraised Value. Minimum Represents fair value of other real estate owned as a percentgage of appraised value, low end of range Fair Value Measurement, Percentage of Appraised Value, Maximum Fair Value Measurement, Percentage of Appraised Value, Maximum Represents fair value of other real estate owned as a percentgage of appraised value, high end of range Fair Value Measurement, Percentage of Appraised Value, Weighted Average Fair Value Measurement, Percentage of Appraised Value, Weighted Average Represents fair value of other real estate owned as a percentgage of appraised value, weighted average Loss Contingency [Abstract] Loss Contingency [Abstract] Loss Contingencies [Table] Loss Contingencies [Table] Loss Contingencies by Nature of Contingency [Axis] Loss Contingency Nature [Axis] Loss Contingency, Nature [Domain] Loss Contingency, Nature [Domain] Visa Membership [Member] Visa Membership [Member] Banks membership in the Visa network and it proportionate share of covered liabilities and benefits. Litigation Status [Axis] Litigation Status [Axis] Litigation Status [Domain] Litigation Status [Domain] Judicial Ruling [Member] Judicial Ruling [Member] Pending Litigation [Member] Pending Litigation [Member] Litigation Case [Axis] Litigation Case [Axis] Litigation Case [Domain] Litigation Case [Domain] Misuse of Revenues Pledged to Municipal Bonds [Member] Misuse of Revenues Pledged to Municipal Bonds [Member] Misuse of Revenues Pledged to Municipal Bonds [Member] Bank Participation in Fraudulent Sale of Securities by Principals [Member] Bank Participation in Fraudulent Sale of Securities by Principals [Member] Bank Participation in Fraudulent Sale of Securities by Principals [Member] Purchase of facilities from principals subject to SEC New Jersey proceedings [Member] Purchase of facilities from principals subject to SEC New Jersey proceedings [Member] Purchase of facilities from principals subject to SEC New Jersey proceedings [Member] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] BOKF Equity, LLC [Member] BOKF Equity, LLC [Member] An indirect, wholly owned subsidiary of the entity that is the general partner of consolidated private equity funds. Loss Contingencies [Line Items] Loss Contingencies [Line Items] Number of Visa Class B Shares Owned by Entity (in shares) Common Stock Class B Shares Owned Number of common stock class B owned by the entity Number of Visa Class A Shares Visa Class B Shares Are Convertible To (in shares) Number of Visa Class A Shares Visa Class B Shares Are Convertible To Represents the number of Visa Class A shares that Visa Class B shares held by the Company are convertible to. Litigation Settlement [Abstract] Outstanding principal, accrued interest and other amounts required by bond documents Outstanding principal, accrued interest and other amounts required by bond documents Outstanding principal, accrued interest and other amounts required by bond documents Disgorged fees Disgorged fees Represents fees disgorged as a result of a settlement with a regulatory agency. Litigation Settlement, Amount Awarded to Other Party Litigation Settlement, Amount Awarded to Other Party Loss Contingency, Number of Plaintiffs Loss Contingency, Number of Plaintiffs Alleged total of judgment against nursing home operator Alleged total of judgment against nursing home operator Alleged total of judgment against nursing home operator Number of individuals who purchased facilities from the principals subject to SEC New Jersey proceedings Number of individuals who purchased facilities from the principals subject to SEC New Jersey proceedings Number of individuals who purchased facilities from the principals subject to SEC New Jersey proceedings Number of principals in SEC New Jersey proceedings Number of principals in SEC New Jersey proceedings Number of principals in SEC New Jersey proceedings Number of Private Equity Funds of which the Entity is a General Partner Number of Private Equity Funds of which the Entity is a General Partner The number of consolidated private equity mutual funds that The Entity is a general partner of. Contingent Obligations For Additional Investments in Private Equity Funds Contingent Obligation For Additional Investments In Private Equity Funds Contingent obligation to make additional investments if limited partners are unable to perform. Statement of Financial Position [Abstract] Assets [Abstract] Assets [Abstract] Investment securities [Abstract] Allowance for real estate and other repossessed assets Real Estate Owned, Valuation Allowance Shareholders' equity: [Abstract] Stockholders' Equity Attributable to Parent [Abstract] Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Common stock, shares authorized (in shares) Common Stock, Shares Authorized Common stock, shares issued (in shares) Common Stock, Shares, Issued Common stock, shares outstanding (in shares) Common Stock, Shares, Outstanding Treasury stock, shares at cost (in shares) Treasury Stock, Shares Statement of Cash Flows [Abstract] Cash Flows From Operating Activities: [Abstract] Net Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to reconcile net income to net cash provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Change in fair value of mortgage servicing rights due to market changes Change in the fair value of mortgage servicing rights due to principal payments Change in fair value of mortgage servicing rights due to loan runoff Represents the non-cash decrease in net pre-tax net income related to the change in fair value of mortgage servicing rights due to loan runoff Net unrealized losses from derivative contracts Unrealized Gain (Loss) on Derivatives Share-based compensation Share-based Compensation Depreciation and amortization Depreciation, Amortization and Accretion, Net Net amortization of securities discounts and premiums Accretion (Amortization) of Discounts and Premiums, Investments Net losses (gains) on financial instruments and other losses (gains), net Realized Investment Gains (Losses) Net gain on mortgage loans held for sale Net gain on mortgage loans held for sale Represents the combined realized net gain from sale of residential mortgage loans and the change in the unrealized net gain on mortgage loans held for sale during the period. Mortgage loans originated for sale Payments for Origination of Mortgage Loans Held-for-sale Proceeds from sale of mortgage loans held for sale Proceeds from Sale of Mortgage Loans Held-for-sale Capitalized mortgage servicing rights Capitalized mortgage servicing rights Represents non-cash adjustment to reconcile net income related to capitalization of mortgage servicing rights. Change in trading and fair value option securities Increase (Decrease) in Trading Securities Change in receivables Increase (Decrease) in Receivables Change in other assets Increase (Decrease) in Other Operating Assets Change in accrued interest, taxes and expense Increase (Decrease) in Other Accounts Payable and Accrued Liabilities Change in other liabilities Increase (Decrease) in Other Operating Liabilities Net cash used in operating activities Net Cash Provided by (Used in) Operating Activities Cash Flows From Investing Activities: [Abstract] Net Cash Provided by (Used in) Investing Activities [Abstract] Proceeds from maturities or redemptions of investment securities Proceeds from Maturities, Prepayments and Calls of Held-to-maturity Securities Proceeds from maturities or redemptions of available for sale securities Proceeds from Maturities, Prepayments and Calls of Available-for-sale Securities Purchases of investment securities Payments to Acquire Held-to-maturity Securities Purchases of available for sale securities Payments to Acquire Available-for-sale Securities Proceeds from sales of available for sale securities Proceeds from Sale of Available-for-sale Securities Change in amount receivable on unsettled securities transactions Change in amount receivable on unsettled security transactions Change in amount receivable on unsettled security transactions. This is an investing cash flow. Loans originated, net of principal collected Payments for (Proceeds from) Loans and Leases Net payments on derivative asset contracts Payments for (Proceeds from) Derivative Instrument, Investing Activities Proceeds from disposition of assets Proceeds from Sale of Productive Assets Purchases of assets Payments to Acquire Productive Assets Net cash provided by (used in) investing activities Net Cash Provided by (Used in) Investing Activities Cash Flows From Financing Activities: [Abstract] Net Cash Provided by (Used in) Financing Activities [Abstract] Net change in demand deposits, transaction deposits and savings accounts Net change in demand deposits, transaction deposits and savings accounts Net change in demand deposits, transaction deposits and savings accounts Net change in time deposits Increase (Decrease) in Time Deposits Net change in other borrowed funds Proceeds from (Repayments of) Debt Net proceeds on derivative liability contracts Payments for (Proceeds from) Derivative Instrument, Financing Activities Net change in derivative margin accounts Net change in derivative margin accounts The net change in derivative margin accounts. Change in amount due on unsettled security transactions Proceeds from (Payments for) Other Financing Activities Issuance of common and treasury stock, net Proceeds from Issuance of Common Stock Repurchase of common stock Payments for Repurchase of Common Stock Dividends paid Payments of Ordinary Dividends, Common Stock Net cash provided by (used in) financing activities Net Cash Provided by (Used in) Financing Activities Net increase in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Cash and cash equivalents at beginning of period Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents at end of period Supplemental Cash Flow Information: [Abstract] Supplemental Cash Flow Information [Abstract] Cash paid for interest Interest Paid, Net Cash paid for taxes Income Taxes Paid, Net Net loans and bank premises transferred to repossessed real estate and other assets Real Estate Owned, Transfer to Real Estate Owned Residential mortgage loans guaranteed by U.S. government agencies that became eligible for repurchase during the period Increase in U.S. government guaranteed loans eligible for repurchase Represents the non-cash increase in loans related to the right but not the obligation to repurchases loans previously sold into Ginnie Mae pools based on certain criteria and as such has effectively regained control of the asset and must recognize the loan on the balance sheet. Conveyance of other real estate owned guaranteed by U.S. government agencies Conveyance of other real estate owned guaranteed by US govt Represents non-cash conveyance of other real estate owned guaranteed by U.S. government agencies during period. Derivatives [Text Block] Derivative Instruments and Hedging Activities Disclosure [Text Block] Reportable Segments [Table Text Block] Schedule of Segment Reporting Information, by Segment [Table Text Block] Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Fair Value, Inputs, Level 1 [Member] Fair Value, Inputs, Level 1 [Member] Fair Value, Inputs, Level 2 [Member] Fair Value, Inputs, Level 2 [Member] Measurement Basis [Axis] Measurement Basis [Axis] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Portion at Fair Value Measurement [Member] Portion at Fair Value Measurement [Member] Carrying (Reported) Amount, Fair Value Disclosure [Member] Reported Value Measurement [Member] Estimate of Fair Value, Fair Value Disclosure [Member] Estimate of Fair Value Measurement [Member] Asset-backed securities Asset-backed Securities [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Cash and due from banks Cash and Cash Equivalents, Fair Value Disclosure Interest-bearing cash and cash equivalents Interest-bearing cash and cash equivalents Represents money market or interest-bearing cash accounts held in other financial institutions (including the Federal Reserve); federal funds sold to other depository institutions, securities brokers or securities dealers and securities purchased under agreements to resell. Trading securities Investment securities Available for sale debt securities Fair value option securities Fair value option securities Fair value option securities represent securities the Company has elected to carry at fair value and separately identified on the balance sheet with changes in fair value recognized in earnings as they occur. Certain residential mortgage-backed securities issued by US government agencies are held as an economic hedge of changes in the fair value of mortgage servicing rights and related derivative contracts. In addition, other securities may be held to manage interest rate risk or for deferred compensation purposes. Securities held for interest rate risk management may be economically hedged by derivative contracts not designated as hedging instruments effectively modify these fixed rate securities into variable rate securities. Residential mortgage loans held for sale Loans Receivable Held-for-sale, Net, Not Part of Disposal Group, Mortgage Loans Loans and Leases Receivable, Gross Allowance for loan losses Loans and Leases Receivable, Allowance Loans, net of allowance Loans and Leases Receivable, Net Amount Mortgage servicing rights Derviative contracts, net of cash collateral, Assets, Fair value Deposits with no stated maturity Deposits No Stated Maturity Fair Value Disclosure This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. May be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. May be used in both the balance sheet and disclosure in the same submission. Represents time deposits with no stated maturity as presented on the statement of financial position. Time deposits Time Deposits Other borrowed funds Other Liabilities, Fair Value Disclosure Subordinated debentures Subordinated Debt Derivative contracts, net of cash collateral, Liabilities, Fair Value Commitments and Contingent Liabilities [Text Block] Commitments and Contingencies Disclosure [Text Block] Cash and due from banks Cash and Due from Banks Interest-bearing cash and cash equivalents Interest-bearing Deposits in Banks and Other Financial Institutions Restricted equity securities Loans, net of allowance Premises and equipment, net Property, Plant and Equipment, Net Receivables Accrued Investment Income Receivable Goodwill Goodwill Intangible assets, net Intangible Assets, Net (Excluding Goodwill) Real estate and other repossessed assets, net of allowance Other Real Estate, Foreclosed Assets, and Repossessed Assets Derivative contracts, net Cash surrender value of bank-owned life insurance Bank Owned Life Insurance Receivable on unsettled securities sales Receivables from Brokers-Dealers and Clearing Organizations Other assets Other Assets Total assets Assets Liabilities and Equity [Abstract] Liabilities and Equity [Abstract] Liabilities: [Abstract] Liabilities [Abstract] Deposits [Abstract] Deposits [Abstract] Noninterest-bearing demand deposits Noninterest-bearing Deposit Liabilities, Domestic Interest-bearing deposits: [Abstract] Interest-bearing Deposit Liabilities [Abstract] Transaction Demand Deposit Accounts Savings Deposits, Savings Deposits Time Total deposits Deposits Funds purchased Federal Funds Purchased Repurchase agreements Securities Sold under Agreements to Repurchase Other borrowings Other Borrowings Accrued interest, taxes and expense Accounts Payable and Accrued Liabilities Derivative contracts, net Due on unsettled securities purchases Payables to Broker-Dealers and Clearing Organizations Other liabilities Other Liabilities Total liabilities Liabilities Common stock Common Stock, Value, Issued Capital surplus Additional Paid in Capital, Common Stock Retained earnings Retained Earnings (Accumulated Deficit) Treasury stock Treasury Stock, Value Accumulated other comprehensive loss Total shareholders’ equity Stockholders' Equity Attributable to Parent Non-controlling interests Stockholders' Equity Attributable to Noncontrolling Interest Total equity Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Total liabilities and equity Liabilities and Equity Components of Residential Mortgage Loans Held For Sale [Table Text Block] Residential Mortgage Loans Held For Sale [Table Text Block] Tabular disclosure of mortgage loans to individuals not classified as held for investment but are held-for-sale. Mortgage Banking Revenue [Table Text Block] Mortgage Banking Revenue [Table Text Block] Mortgage Banking Revenue [Table Text Block] Summary of Mortgage Servicing Rights [Table Text Block] Summary of Mortgage Servicing Rights [Table Text Block] Tabular disclosure of the summary of residential mortgage servicing rights as measured at balance sheet date. Activity in Capitalized Mortgage Servicing Rights [Table Text Block] Schedule of Servicing Assets at Fair Value [Table Text Block] Assumptions to Value Mortgage Servicing Rights [Table Text Block] Assumptions to Value Mortgage Servicing Rights [Table Text Block] Assumptions to Value Mortgage Servicing Rights [Table Text Block] Aging Status of Mortgage Loans Serviced For Others [Table Text Block] Aging Status of Mortgage Loans Serviced For Others [Table Text Block] Tabular disclosure of all Mortgage Loans Serviced For Others by aging status. Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Energy Producers [Member] Energy Producers [Member] Energy Producers [Member] Geographical [Axis] Geographical [Axis] Geographical [Domain] Geographical [Domain] Texas [Member] TEXAS Oklahoma [Member] OKLAHOMA Colorado COLORADO Concentration Risk Type [Axis] Concentration Risk Type [Axis] Concentration Risk Type [Domain] Concentration Risk Type [Domain] Geographic Concentration Risk [Member] Geographic Concentration Risk [Member] Credit Concentration Risk [Member] Credit Concentration Risk [Member] Accounts, Notes, Loans and Financing Receivable [Line Items] Accounts, Notes, Loans and Financing Receivable [Line Items] Loan receivables disclosure [Abstract] Loans and Leases Receivable Disclosure [Abstract] Loans, fixed rate of interest Loans Receivable with Fixed Rates of Interest Loans, variable rate of interest Loans Receivable with Variable Rates of Interest Loans, non-accrual Loans and Leases Receivable, Nonperforming, Nonaccrual of Interest Total Accruing loans past due (90 days) Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing Loans receivable, other information [Abstract] Loans and Leases Receivable, Other Information [Abstract] Percentage of loan portfolio attributed to Texas (in hundredths) Percentage of Loan Portfolio Attributed to Texas Reflects the percentage of the loan portfolio attributed to Texas. Percentage of loan portfolio attributed to Oklahoma (in hundredths) Percentage of Loan Portfolio Attributed to Oklahoma Reflects the percentage of the loan portfolio attributed to Oklahoma. Percentage of loan portfolio attributed to Colorado (in hundredths) Percentage of Loan Portfolio Attributed to Colorado Percentage of Loan Portfolio Attributed to Colorado Percentage of loan class to total loans Percentage of Loan Class to Total Loans Represents percentage of given loan class to total loans. Percentage of committed energy production loans secured by oil Percentage of committed energy production loans secured by oil Percentage of committed energy production loans secured by properties primarily producing oil Percentage of committed energy production loans secured by natural gas Percentage of committed energy production loans secured by natural gas Percentage of committed energy production loans secured by properties producing natural gas Amount of loans with individual balances less than $10 million Maximum Amount Of Loans With Balances Below Threshold Maximum dollar amount of loans in this category with individual loan amount less than specified threshold. Maximum loan amount for certain individual loans in category Maximum Loan Amount For Certain Individual Loans In Category Maximum loan amount for specified individual loans in category. Percentage of loan portfolio secured by property in Texas (in hundredths) Percentage of Loan Portfolio Secured By Property in Texas Reflects the percentage of the loan in portfolio secured by property in the state of Texas. Percentage of loan portfolio secured by property in Oklahoma (in hundredths) Percentage of Loan Portfolio Secured By Property in Oklahoma Reflects the percentage of the loan in portfolio secured by property in the state of Oklahoma. Minimum FICO required for jumbo loan approval Minimum FICO Required For Loan Approval Represents the minimum FICO score required for loan approval. Maximum debt-to-income ratio on jumbo loans (in hundredths) Maximum Debt To Income Ratio On Loans Represents the maximum debt-to-income (DTI) ratio on loans approved. Minimum loan-to-value ratio on jumbo loans (in hundredths) Minimum Loan To Value Ratio On Loans Represents the minimum loan-to-value (LTV) ratio acceptable for loans to be approved. Maximum loan-to-value ratio on jumbo loans (in hundredths) Maximum Loan To Value Ratio On Loans Represents the maximum loan-to-value (LTV) ratio on loans approved. Minimum period for fixed rate on variable rate jumbo loans (in years) Minimum Period For Fixed Rate On Variable Rate Jumbo Residential Mortgage Loans The minimum number o years that a variable rate jumbo residential mortgage loan will have a fixed rate of interest. Maximum period for fixed rate on variable rate jumbo loans (in years) Maximum Period for Fixed Rate on Variable Rate Jumbo Residential Mortgage Loan Represent the maximum number of years that a variable rate jumbo residential mortgage loan will have a fixed rate of interest. Percentage of home equity portfolio comprised of first lien loans Percentage of home equity portfolio comprised of first lien loans Percentage of home equity portfolio comprised of first lien loans Percentage of home equity portfolio comprised of junior lien loans Percentage of home equity portfolio comprised of junior lien loans Percentage of home equity portfolio comprised of junior lien loans Percentage of junior lien home equity loans that are amortizing term loans Percentage of junior lien home equity loans that are amortizing term loans Percentage of junior lien home equity loans that are amortizing term loans Percentage of junior lien home equity loans that are revolving lines of credit Percentage of junior lien home equity loans that are revolving lines of credit Percentage of junior lien home equity loans that are revolving lines of credit Home equity loans, description Home equity loans, description Describes the general components and status of home equity loans serviced by the entity outstanding as of the Balance Sheet date. Home equity loans, maximum Home equity loans, maximum The generally accepted maximum loan amount for a home equity loan issued by the Company. Home equity loans, revolving period Revolving Period for Home Equity Loans Represents the revolving period for home equity loans. Home equity loans, amortization period following revolving period Amortization Period Following Revolving Period for Home Equity Loans Represents the amortization period of repayment following the revolving period for home equity loans. Home equity loans, discretionary additional revolving period Home Equity Loans, Additional Discretionary Revolving Period Represents additional revolving period that may be extended at the discretion of management following the initial revolving period for home equity loans. Credit Commitments [Abstract] Credit Commitments [Abstract] -- None. No documentation exists for this element. -- Outstanding commitments to extend credit Unused Commitments to Extend Credit Outstanding standby letters of credit Letters of Credit Outstanding, Amount Fair Value Assets And Liabilities Measured On A Recurring Basis [Table Text Block] Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Fair Value Assets Measured On Recurring Basis, Significant Unobservable Inputs [Table Text Block] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Fair Value Inputs, Fair Value Measured On a Recurring Basis, Quantitative Information [Table Text Block] Fair Value Inputs, Fair Value Measured On a Recurring Basis, Quantitative Information [Table Text Block] Fair Value Inputs, Fair Value Measured On a Recurring Basis, Quantitative Information [Table Text Block] Fair Value Assets Measured on Nonrecurring Basis [Table Text Block] Fair Value Measurements, Nonrecurring [Table Text Block] Fair Value Inputs, Fair Value Measured On a Nonrecurring Basis, Quantitative Information [Table Text Block] Fair Value Inputs, Fair Value Measured On a Nonrecurring Basis, Quantitative Information [Table Text Block] Fair Value Inputs, Fair Value Measured On a Nonrecurring Basis, Quantitative Information [Table Text Block] Fair Value of Financial Instruments [Table Text Block] Fair Value, by Balance Sheet Grouping [Table Text Block] Derivative Instruments, Gain (Loss) by Hedging Relationship, by Income Statement Location, by Derivative Instrument Risk [Table] Derivative Instruments, Gain (Loss) [Table] Derivative Instruments, Gain (Loss) [Line Items] Derivative Instruments, Gain (Loss) [Line Items] Derivative Instruments, Gain (Loss) Recognized in Income, Net [Abstract] Derivative, Gain (Loss) on Derivative, Net [Abstract] Brokergage and Trading Revenue Trading Gain (Loss) Gain (Loss) on Derivatives, Net Derivative, Gain (Loss) on Derivative, Net Marketable Securities [Abstract] Securities [Text Block] Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Mortgage Banking Revenue [Abstract] Mortgage Banking Revenue [Abstract] Net realized gains on sale of mortgage loans Gain (Loss) on Sale of Mortgage Loans Net change in unrealized gain on mortgage loans held for sale Net change in unrealized gain on mortgage loans held for sale Represents the net change in unrealized gain on mortgage loans held for sale under fair value option. Net change in the fair value of mortgage loan commitments Change in fair value of mortgage loan commitments Represents the change in fair value of mortgage loan commitments during the period. Net change in the fair value of forward sales contracts Change in the fair value of forward sales commitments Represents the change in the fair value of forward sales commitments considered to be derivative instruments during the period. Total production revenue Mortgage Production Revenue Total gain (loss) on mortgage loans held for sale, including mortgage loan commitments and forward sales contracts. Servicing revenue Bank Servicing Fees Total mortgage banking revenue Schedule of Financing Receivables Past Due [Table] Schedule of Financing Receivables Past Due [Table] Financing Receivables, Period Past Due [Axis] Financing Receivables, Period Past Due [Axis] Financing Receivables, Period Past Due [Domain] Financing Receivables, Period Past Due [Domain] 30 to 59 Days [Member] Financing Receivables, 30 to 59 Days Past Due [Member] 60 to 89 Days [Member] Financing Receivables, 60 to 89 Days Past Due [Member] 90 Days or More [Member] Financing Receivables, Equal to Greater than 90 Days Past Due [Member] Financing Receivable, Recorded Investment, Past Due [Line Items] Financing Receivable, Recorded Investment, Past Due [Line Items] Financing receivable, recorded investment, aging [Abstract]