XML 51 R39.htm IDEA: XBRL DOCUMENT
v3.4.0.3

Loans and Allowance for Loan Losses - Additional Information (Detail) | 3 Months Ended
--- | ---
Mar. 31, 2016 USD ($) SecurityLoan | Mar. 31, 2015 USD ($)
Receivables [Abstract] |  |
Percentage of loans secured by real estate | 65.00% |
Interest income recognized | $ | $ 513,000 | $ 310,000
Troubled debt restructuring principal deferral | SecurityLoan | 1 |

X
- Definition Percentage of loans secured by real estate. + References No definition available. + Details
Name: | banf_PercentageOfLoansSecuredByRealEstate
Namespace Prefix: | banf_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of financing receivables that have been modified by troubled debt restructurings. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 33 -URI http://asc.fasb.org/extlink&oid=49124121&loc=SL6953676-111524 + Details
Name: | us-gaap_FinancingReceivableModificationsNumberOfContracts2
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Reflects the amount of additional interest income that would have been recorded if impaired or nonperforming loans were instead current, in compliance with their original terms, and outstanding throughout the reporting period or since origination (if held for part of the period). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 40 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=25495931&loc=d3e18794-111554 + Details
Name: | us-gaap_LoansAndLeasesReceivableImpairedInterestLostOnNonaccrualLoans
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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