XML 78 R71.htm IDEA: XBRL DOCUMENT
v3.25.3

Derivative Financial Instruments - Additional Information (Detail) - USD ($) | 9 Months Ended |
--- | --- | ---
Sep. 30, 2025 | Dec. 31, 2024
Derivative [Line Items] |  |
Percentage share of total profit | 35.00% |
Other Assets [Member] | Oil and Gas Reserves [Member] |  |
Derivative [Line Items] |  |
Derivative instrument asset margin amount | $ 48,000 | $ 463,000

X
- Definition Derivative iasset margin amount. + References No definition available. + Details
Name: | banf_DerivativeInstrumentAssetMarginAmount
Namespace Prefix: | banf_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Derivative instrument, percentage of share profit. + References No definition available. + Details
Name: | banf_DerivativeInstrumentPercentageOfShareProfit
Namespace Prefix: | banf_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 815 -SubTopic 20 -Name Accounting Standards Codification -Section 25 -Paragraph 6A -Publisher FASB -URI https://asc.fasb.org/1943274/2147480682/815-20-25-6A Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 815 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480237/815-40-50-5 + Details
Name: | us-gaap_DerivativeLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_BalanceSheetLocationAxis=us-gaap_OtherAssetsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=banf_OilAndGasReservesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |