Recent Developments Including Mergers and Acquisitions - Additional Information (Detail)	Jul. 20, 2023 USD ($)	Feb. 08, 2022 USD ($) Location	Sep. 30, 2023 USD ($)	Dec. 31, 2022 USD ($)
Business Combination Separately Recognized Transactions [Line Items]
Total assets			$ 12,114,602,000	$ 12,387,863,000
Loans held for investment (net of unearned interest)			7,472,622,000	6,943,563,000
Deposits			10,534,171,000	10,974,228,000
Goodwill			$ 182,263,000	$ 182,055,000
RCB Bank [Member]
Business Combination Separately Recognized Transactions [Line Items]
Total assets	$ 2,500,000
Loans held for investment (net of unearned interest)	2,100,000
Deposits	10,800,000
Proceeds from acquisition	7,800,000
Intangibles assets, net	252,280
Goodwill	$ 208,752
Worthington [Member]
Business Combination Separately Recognized Transactions [Line Items]
Purchase price		$ 77,700,000
Total assets		478,000,000
Loans held for investment (net of unearned interest)		257,000,000
Deposits		430,000,000
Intangibles assets, net		5,900,000
Goodwill		$ 32,100,000
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