XML 68 R55.htm IDEA: XBRL DOCUMENT
v3.20.4

Cash Due from Banks, Interest-Bearing Deposits and Federal Funds Sold - Additional Information (Detail) | Mar. 26, 2020
--- | ---
Cash And Cash Equivalents [Abstract] |
Reserve requirement ratio | 0.00%

X
- Definition Reserve requirement ratios. + References No definition available. + Details
Name: | banf_ReserveRequirementRatios
Namespace Prefix: | banf_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

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