XML 58 R57.htm IDEA: XBRL DOCUMENT
v3.19.3

Fair Value Measurements, Measured On Recurring Basis Significant Unobservable Inputs (Details) - Fair Value, Recurring [Member] - Fair Value, Inputs, Level 3 [Member] - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2019 | Sep. 30, 2018 | Sep. 30, 2019 | Sep. 30, 2018
Available-for-sale securities [Member] | Municipal and other tax-exempt securities [Member] |  |  |  |  |  |  |  |
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward] |  |  |  |  |  |  |  |
Balance, beginning of period |  |  | $ 2,030 |  |  |  | $ 4,802 |
Transfer to Level 3 from Level 2 |  |  | 0 | [1] |  |  | 0 | [2]
Purchases |  |  | 0 |  |  |  | 0 |
Proceeds from sales |  |  | 0 |  |  |  | 0 |
Redemptions and distributions |  |  | (2,050) |  |  |  | (5,095) |
Other comprehensive income (loss) |  |  | 20 |  |  |  | 293 |
Balance, end of period |  |  | 0 |  |  |  | 0 |
Available-for-sale securities [Member] | Municipal and other tax-exempt securities [Member] | Mortgage banking revenue [Member] |  |  |  |  |  |  |  |
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward] |  |  |  |  |  |  |  |
Gain (loss) recognized in earnings |  |  | 0 |  |  |  | 0 |
Available-for-sale securities [Member] | Other debt securities [Member] |  |  |  |  |  |  |  |
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward] |  |  |  |  |  |  |  |
Balance, beginning of period | $ 472 |  | 471 |  | $ 472 |  | 472 |
Transfer to Level 3 from Level 2 | 0 | [3] | 0 | [1] | 0 | [3] | 0 | [2]
Purchases | 0 |  | 0 |  | 0 |  | 0 |
Proceeds from sales | 0 |  | 0 |  | 0 |  | 0 |
Redemptions and distributions | 0 |  | 0 |  | 0 |  | 0 |
Other comprehensive income (loss) | 0 |  | 1 |  | 0 |  | 0 |
Balance, end of period | 472 |  | 472 |  | 472 |  | 472 |
Available-for-sale securities [Member] | Other debt securities [Member] | Mortgage banking revenue [Member] |  |  |  |  |  |  |  |
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward] |  |  |  |  |  |  |  |
Gain (loss) recognized in earnings | 0 |  | 0 |  | 0 |  | 0 |
Residential mortgage loans held for sale [Member] |  |  |  |  |  |  |  |
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward] |  |  |  |  |  |  |  |
Balance, beginning of period | 16,073 |  | 14,243 |  | 15,207 |  | 12,299 |
Transfer to Level 3 from Level 2 | 261 | [3] | 2,862 | [1] | 2,150 | [3] | 5,603 | [2]
Purchases | 0 |  | 0 |  | 0 |  | 0 |
Proceeds from sales | (3,152) |  | (143) |  | (4,531) |  | (853) |
Redemptions and distributions | 0 |  | 0 |  | 0 |  | 0 |
Other comprehensive income (loss) | 0 |  | 0 |  | 0 |  | 0 |
Balance, end of period | 13,568 |  | 16,838 |  | 13,568 |  | 16,838 |
Residential mortgage loans held for sale [Member] | Mortgage banking revenue [Member] |  |  |  |  |  |  |  |
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward] |  |  |  |  |  |  |  |
Gain (loss) recognized in earnings | $ 386 |  | $ (124) |  | $ 742 |  | $ (211) |
[1] | Recurring transfers to Level 3 from Level 2 consist of residential mortgage loans intended for sale to U.S. government agencies that fail to meet conforming standards.
[2] | Recurring transfers to Level 3 from Level 2 consist of residential mortgage loans intended for sale to U.S. government agencies that fail to meet conforming standards.
[3] | Recurring transfers to Level 3 from Level 2 consist of residential mortgage loans intended for sale to U.S. government agencies that fail to meet conforming standards.

X
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
Name: | us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of gain (loss) recognized in income from asset measured at fair value on recurring basis using unobservable input (level 3). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of gain (loss) recognized in other comprehensive income (OCI) from asset measured at fair value on recurring basis using unobservable input (level 3). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1a) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncomeLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of purchases of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of sale of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of settlement of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of transfer of financial instrument classified as an asset into level 3 of the fair value hierarchy. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(3) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersIntoLevel3
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Fair value of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_AvailableforsaleSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_USStatesAndPoliticalSubdivisionsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IncomeStatementLocationAxis=bokf_MortgagebankingrevenueMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_OtherDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=bokf_ResidentialMortgageLoansHeldforSaleMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |