XML 52 R42.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Loans and Allowance for Loan Losses - Internal Loan Grading by Class of Loans (Detail) - USD ($) $ in Thousands | Sep. 30, 2018 | Dec. 31, 2017
--- | --- | ---
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | $ 4,947,528 | $ 4,721,995
Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 630,422 | 641,618
Real Estate [Member] | Non-residential Real Estate Other [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 1,117,450 | 1,126,591
Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 328,426 | 330,334
Real Estate [Member] | Residential Real Estate All Other [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 817,884 | 785,655
Commercial and Financial [Member] | Non-consumer Non-real Estate [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 1,270,080 | 1,284,405
Consumer Non-real Estate [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 320,432 | 288,920
Other Loans [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 143,205 | 144,445
Acquired Loans [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 319,629 | 120,027
Grade 1 [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 3,916,921 | 3,851,837
Grade 1 [Member] | Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 478,014 | 520,641
Grade 1 [Member] | Real Estate [Member] | Non-residential Real Estate Other [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 913,259 | 931,295
Grade 1 [Member] | Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 280,194 | 289,200
Grade 1 [Member] | Real Estate [Member] | Residential Real Estate All Other [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 641,246 | 621,401
Grade 1 [Member] | Commercial and Financial [Member] | Non-consumer Non-real Estate [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 980,535 | 1,018,172
Grade 1 [Member] | Consumer Non-real Estate [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 297,516 | 268,826
Grade 1 [Member] | Other Loans [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 137,705 | 136,617
Grade 1 [Member] | Acquired Loans [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 188,452 | 65,685
Grade 2 [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 901,743 | 758,681
Grade 2 [Member] | Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 131,597 | 105,696
Grade 2 [Member] | Real Estate [Member] | Non-residential Real Estate Other [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 181,829 | 178,282
Grade 2 [Member] | Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 38,452 | 33,033
Grade 2 [Member] | Real Estate [Member] | Residential Real Estate All Other [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 156,018 | 149,201
Grade 2 [Member] | Commercial and Financial [Member] | Non-consumer Non-real Estate [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 268,882 | 234,884
Grade 2 [Member] | Consumer Non-real Estate [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 19,975 | 17,499
Grade 2 [Member] | Other Loans [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 5,304 | 5,668
Grade 2 [Member] | Acquired Loans [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 99,686 | 34,418
Grade 3 [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 99,908 | 88,588
Grade 3 [Member] | Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 19,221 | 13,852
Grade 3 [Member] | Real Estate [Member] | Non-residential Real Estate Other [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 15,238 | 14,290
Grade 3 [Member] | Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 8,093 | 6,352
Grade 3 [Member] | Real Estate [Member] | Residential Real Estate All Other [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 15,000 | 9,418
Grade 3 [Member] | Commercial and Financial [Member] | Non-consumer Non-real Estate [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 14,915 | 24,322
Grade 3 [Member] | Consumer Non-real Estate [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 2,202 | 2,038
Grade 3 [Member] | Other Loans [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 157 | 1,203
Grade 3 [Member] | Acquired Loans [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 25,082 | 17,113
Grade 4 [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 28,707 | 22,859
Grade 4 [Member] | Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 1,590 | 1,429
Grade 4 [Member] | Real Estate [Member] | Non-residential Real Estate Other [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 7,124 | 2,724
Grade 4 [Member] | Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 1,687 | 1,749
Grade 4 [Member] | Real Estate [Member] | Residential Real Estate All Other [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 5,620 | 5,635
Grade 4 [Member] | Commercial and Financial [Member] | Non-consumer Non-real Estate [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 5,748 | 6,997
Grade 4 [Member] | Consumer Non-real Estate [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 739 | 557
Grade 4 [Member] | Other Loans [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 39 | 957
Grade 4 [Member] | Acquired Loans [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 6,160 | 2,811
Grade 5 [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | 249 | 30
Grade 5 [Member] | Commercial and Financial [Member] | Non-consumer Non-real Estate [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans |  | $ 30
Grade 5 [Member] | Acquired Loans [Member] |  |
Financing Receivable Recorded Investment [Line Items] |  |
Total loans | $ 249 |

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

X
- Definition Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=82891408&loc=d3e4428-111522 + Details
Name: | us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=banf_RealEstatePortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=banf_NonResidentialRealEstateOwnerOccupiedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=banf_NonResidentialRealEstateOtherMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=banf_ResidentialRealEstatePermanentMortgageMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=banf_ResidentialRealEstateAllOtherMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=banf_NonConsumerNonRealEstateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=banf_ConsumerNonRealEstateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=banf_OtherLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=banf_AcquiredLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=banf_GradeOneMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=banf_GradeTwoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=banf_GradeThreeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=banf_GradeFourMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=banf_GradeFiveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |