Financing receivable modifications due to impact of CARES act.

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- Definition

Nonaccrual loan amount guaranteed by government agencies.

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Paycheck protection program amortized processing fees recognized as interest income.

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- Definition

Percentage of loans secured by real estate.

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No definition available.

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- Definition

Amount of credit loss expense (reversal of expense) for financing receivable from change in methodology.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 20
-Section 50
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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.

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- Definition

The net gain (loss) resulting from sales and other disposals of other real estate owned, increases (decreases) in the valuation allowance for foreclosed real estate, and write-downs of other real estate owned after acquisition or physical possession.

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- 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).

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- Definition

Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

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Additions of other real estate not separately disclosed, including, but not limited to, real estate investments, real estate loans that qualify as investments in real estate, and premises that are no longer used in operations may also be included in real estate owned. This excludes real estate assets taken in settlement of troubled loans through surrender or foreclosure.

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Amount of increase (decrease) of physical assets used in the normal conduct of business and not intended for resale, from reclassification, impairment, donation, or changes classified as other. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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Loans Held for Investment and Allowance for Credit Losses on Loans - Additional Information (Detail) - USD ($)		3 Months Ended		6 Months Ended		12 Months Ended
	Jan. 01, 2020	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	May 20, 2021
Financing Receivable Recorded Investment [Line Items]
Paycheck protection program amortized processing fees recognized as interest income		$ 21,700,000	$ 3,700,000	$ 11,900,000	$ 3,700,000
Total loans		6,191,230,000		6,191,230,000		$ 6,394,506,000
Gains (losses) on sale of property held in other real estate owned				(105,000)	2,300,000
Interest income that would have been recognized				1,200	983,000,000
Decrease in allowance for credit losses upon adoption of ASC 326	$ 3,200,000				3,195,000
Commercial Real Estate
Financing Receivable Recorded Investment [Line Items]
Loans modification		$ 61,800,000		61,800,000		81,700,000
U.S. Federal Agencies [Member]
Financing Receivable Recorded Investment [Line Items]
Nonaccrual loans guaranteed by government agencies				3,500,000		7,800,000
Previous Corporate Headquarters [Member] \| Other Real Estate Owned [Member]
Financing Receivable Recorded Investment [Line Items]
Transferred premises and equipment to other real estate				2,400,000
First National Bank and Trust [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans							$ 195,000,000
First National Bank and Trust [Member] \| Oklahoma [Member]
Financing Receivable Recorded Investment [Line Items]
Other real estate owned purchased				$ 2,500,000
BancFirst’s [Member]
Financing Receivable Recorded Investment [Line Items]
Percentage of loans secured by real estate		56.00%		56.00%
Pegasus Bank [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans		$ 586,043,000		$ 586,043,000		554,548,000
Decrease in allowance for credit losses upon adoption of ASC 326					$ (2,488,000)
Pegasus Bank [Member] \| Real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Percentage of loans secured by real estate		51.00%		51.00%
Total loans		$ 297,000,000		$ 297,000,000
Pegasus Bank [Member] \| Commercial and Agricultural Non-Real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans		$ 268,000,000		$ 268,000,000		$ 262,000,000