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Number of banking locations.

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Amount of intangible assets, excluding goodwill, acquired at the acquisition date.

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Recent Developments, Including Mergers and Acquisitions - Additional Information (Detail) $ in Thousands				3 Months Ended
	Feb. 08, 2022 USD ($) Location	Jun. 17, 2021 USD ($)	May 20, 2021 USD ($) Location	Jun. 30, 2021 USD ($)	Mar. 31, 2021 USD ($)	Mar. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Jan. 22, 2021 USD ($)
Business Combination Separately Recognized Transactions [Line Items]
Total assets						$ 12,624,431	$ 9,405,612
Loans held for investment (net of unearned interest)						6,494,340	6,169,442
Deposits						11,250,971	8,091,914
Goodwill						$ 176,563	$ 149,922
First National Bank and Trust [Member]
Business Combination Separately Recognized Transactions [Line Items]
Purchase price			$ 21,000
Total assets			284,000
Loans held for investment (net of unearned interest)			195,000
Deposits			256,000
Bargain purchase gain				$ 4,800
Purchase expenses				$ 4,800
Intangibles assets, net			$ 1,700
Subordinated Notes due 2036 [Member] \| Private Placement [Member]
Business Combination Separately Recognized Transactions [Line Items]
Aggregate principal amount		$ 60,000
Fixed-to-floating rate		3.50%
Debt instrument maturity year		2036
Oklahoma [Member]
Business Combination Separately Recognized Transactions [Line Items]
Sale of Loans								$ 21,000
Deposits sold								$ 38,000
Oklahoma [Member] \| Noninterest Income [Member]
Business Combination Separately Recognized Transactions [Line Items]
Gain on transaction					$ 2,500
Oklahoma [Member] \| First National Bank and Trust [Member]
Business Combination Separately Recognized Transactions [Line Items]
Number of banking locations \| Location			2
Worthington [Member]
Business Combination Separately Recognized Transactions [Line Items]
Purchase price	$ 77,700
Total assets	484,000
Loans held for investment (net of unearned interest)	257,000
Deposits	430,000
Intangibles assets, net	8,700
Goodwill	$ 26,600
Worthington [Member] \| Arlington, Texas [Member]
Business Combination Separately Recognized Transactions [Line Items]
Number of banking locations \| Location	1
Worthington [Member] \| Colleyville, Texas [Member]
Business Combination Separately Recognized Transactions [Line Items]
Number of banking locations \| Location	1
Worthington [Member] \| Fort Worth, Texas [Member]
Business Combination Separately Recognized Transactions [Line Items]
Number of banking locations \| Location	2