XML 69 R59.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Stockholders' Equity - Additional Information (Detail) | 6 Months Ended
--- | ---
Jun. 30, 2018 USD ($)
2016 [Member] |
Stockholders Equity [Line Items] |
Implementation of the capital conservation buffer, Percentage | 0.625%
Capital conservation buffer implementation phase-in period | 4 years
2019 [Member] |
Stockholders Equity [Line Items] |
Capital Conservation Buffer Maximum Level | 2.50%
Maximum [Member] |
Stockholders Equity [Line Items] |
Quantitative limit for trust preferred securities to be included in tier 1 capital | $ 15,000,000,000

X
- Definition Quantitative limit for trust preferred securities to be included in tier one capital. + References No definition available. + Details
Name: | banf_QuantitativeLimitForTrustPreferredSecuritiesToBeIncludedInTierOneCapital
Namespace Prefix: | banf_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Stockholders equity. + References No definition available. + Details
Name: | banf_StockholdersEquityLineItems
Namespace Prefix: | banf_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tier one capital conservation buffer maximum level. + References No definition available. + Details
Name: | banf_TierOneCapitalConservationBufferMaximumLevel
Namespace Prefix: | banf_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Tier one capital conservation buffer to risk weighted assets required under regulatory. + References No definition available. + Details
Name: | banf_TierOneCapitalConservationBufferToRiskWeightedAssetsRequiredUnderRegulatory
Namespace Prefix: | banf_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tier one risk based capital conservation buffer initial requirements phasing duration. + References No definition available. + Details
Name: | banf_TierOneRiskBasedCapitalConservationBufferInitialRequirementsPhasingDuration
Namespace Prefix: | banf_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_CreationDateAxis=banf_TwoThousandAndSixteenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CreationDateAxis=banf_TwoThousandAndNineteenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |