XML 21 R59.htm IDEA: XBRL DOCUMENT
v3.19.3

Stock-Based Compensation - Summary of Accumulated Stock Units (Detail) - $ / shares | Sep. 30, 2019 | Dec. 31, 2018
--- | --- | ---
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] |  |
Accumulated stock units | 141,086 | 143,347
Average price | $ 26.68 | $ 24.91

X
- Definition Deferred compensation arrangement with individual accumulated stock units For deferred board fees. + References No definition available. + Details
Name: | banf_DeferredCompensationArrangementWithIndividualAccumulatedStockUnitsForDeferredBoardFees
Namespace Prefix: | banf_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Deferred compensation arrangement with individual stock average price. + References No definition available. + Details
Name: | banf_DeferredCompensationArrangementWithIndividualStockAveragePrice
Namespace Prefix: | banf_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration