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Commitments and Contingent Liabilities - Additional Information (Detail) | 12 Months Ended
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Dec. 31, 2013 Buildings ParkingSpaces ATM Land_Parcel StorageSpaces
Commitments And Contingencies Disclosure [Abstract] |
Number of buildings | 14
Parcels of land | 2
Number of ATM locations | 19
Number of storage facilities | 3
Number of parking lots | 3
Lease expiry period maximum | 2064

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- Definition Lease Expiry Period Maximum + References No definition available. + Details
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Namespace Prefix: | banf_
Data Type: | xbrli:gYearItemType
Balance Type: | na
Period Type: | duration

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- Definition Number Of Leased Atm Locations + References No definition available. + Details
Name: | banf_NumberOfLeasedAtmLocations
Namespace Prefix: | banf_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

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- Definition Number of Leased Buildings + References No definition available. + Details
Name: | banf_NumberOfLeasedBuildings
Namespace Prefix: | banf_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

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- Definition Number Of Leased Parcels Of Land + References No definition available. + Details
Name: | banf_NumberOfLeasedParcelsOfLand
Namespace Prefix: | banf_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

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- Definition Number Of Parking Lots + References No definition available. + Details
Name: | banf_NumberOfParkingLots
Namespace Prefix: | banf_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

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- Definition Number Of Storage Facilities + References No definition available. + Details
Name: | banf_NumberOfStorageFacilities
Namespace Prefix: | banf_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

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- Details
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Namespace Prefix: | us-gaap_
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