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Fair Value Measurements - Additional Information (Detail) - USD ($) | 12 Months Ended
--- | ---
Dec. 31, 2019 | Dec. 31, 2018
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] |  |
Transfer of securities between levels of fair value hierarchy | $ 0 | $ 0
Days from origination after which mortgage loans are sold | 30 days |
Amount of non-financial assets (liabilities) measured at fair value on a recurring basis | $ 0 | 0
Non-financial assets or liabilities for which no impairment was provided |  | $ 0
Customer Related Intangibles [Member] | BancFirst Insurance Services, Inc. [Member] |  |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] |  |
Impairment of intangible assets | $ 353,000 |

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- Definition Non financial assets liabilities for which no impairment provided. + References No definition available. + Details
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- Definition Amount of non-financial assets (liabilities) measured at fair value on a recurring basis. + References No definition available. + Details
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- Definition Period for sale of mortgage loan from origination. + References No definition available. + Details
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- 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
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- Definition Amount of transfers of financial instrument classified as a liability into (out of) level 3 of the fair value hierarchy. + References No definition available. + Details
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- Definition The amount of impairment loss recognized in the period resulting from the write-down of the carrying amount of a finite-lived intangible asset to fair value. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16373-109275 + Details
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