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v3.20.4

Commitments and Contingent Liabilities (Details) | 12 Months Ended
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Dec. 31, 2020 USD ($) shares | Dec. 31, 2019 USD ($)
Other Commitments [Abstract] |  |
The Net Asset Value of Units in Mutual Funds (per unit) | 1.00 |
Assets Purchased from Mutual Funds Managed |  | $ 0
Minimum Average Cash Balance Required to be Maintained at Federal Reserve by Subsidiary Bank | $ 727,000,000 | $ 618,000,000
Misuse of Revenues Pledged to Municipal Bonds [Member] | Judicial Ruling [Member] |  |
Litigation Settlement [Abstract] |  |
Disgorged fees | 1,067,721 |
Litigation Settlement, Expense | $ 600,000 |
Misuse of Revenues Pledged to Municipal Bonds [Member] | Pending Litigation [Member] |  |
Litigation Settlement [Abstract] |  |
Loss Contingency, Number of Plaintiffs | 2 |
Alleged total of judgment against nursing home operator | $ 8,000,000 |
Bank Participation in Fraudulent Sale of Securities by Principals [Member] | Pending Litigation [Member] |  |
Litigation Settlement [Abstract] |  |
Loss Contingency, Number of Plaintiffs | 19 |
Principal amount of entered judgment against the principal individual and his wife | $ 36,805,051 |
Pre-judgment interest amount of entered judgment against the principal individual and his wife | 10,937,831 |
Outstanding principal accrued interest and other amounts upon sale of facilities securing payment of the bonds | $ 20,000,000 |
Purchase of facilities from principals subject to SEC New Jersey proceedings [Member] | Settled Litigation |  |
Litigation Settlement [Abstract] |  |
Number of individuals who purchased facilities from the principals subject to SEC New Jersey proceedings | 2 |
Outstanding principal, accrued interest and other amounts required by bond documents | $ 60,000,000 |
Visa Membership [Member] |  |
Loss Contingencies [Line Items] |  |
Number of Visa Class B Shares Owned by Entity (in shares) | shares | 252,233 |
Number of Visa Class A Shares Visa Class B Shares Are Convertible To (in shares) | shares | 409,324 |

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- Definition Represents the amount of assets purchased from managed Cavanal Hill Funds in order to maintain the net asset value of $1.00. + References No definition available. + Details
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- Definition Minimum Average Cash Balance Required to be Maintained at Federal Reserve by Subsidiary Bank + References No definition available. + Details
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- Definition Represents the net asset value of units in Cavanal Hill Funds that BOK Financial may, but is not obligated to purchase assets to maintain the net asset value. + References No definition available. + Details
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- Definition Represents the number of Visa Class A shares that Visa Class B shares held by the Company are convertible to. + References No definition available. + Details
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- Definition Number of individuals who purchased facilities from the principals subject to SEC New Jersey proceedings + References No definition available. + Details
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- Definition Outstanding principal accrued interest and other amounts upon sale of facilities securing payment of the bonds + References No definition available. + Details
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