XML 65 R55.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Stock - Based Compensation - Summary of Accumulated Stock Units (Detail) - $ / shares | Sep. 30, 2018 | Dec. 31, 2017
--- | --- | ---
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] |  |
Accumulated stock units | 140,946 | 138,768
Average price | $ 24.36 | $ 22.84

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