Acquisitions - Schedule of Preliminary Estimated Fair Value Amounts Assigned to Major Asset and Liability Categories at Acquisition Date (Detail) - USD ($)	Dec. 31, 2022	Dec. 31, 2021	Jan. 01, 2020
Business Acquisition [Line Items]
Goodwill and intangible assets with indefinite lives	$ 313,481,000	$ 313,481,000
TB&T Bancshares, Inc. and The Bank & Trust of Bryan College Station, Texas [Member]
Business Acquisition [Line Items]
Cash and cash equivalents			$ 61,028,000
Securities available-for-sale			93,967,000
Loans			447,702,000
Identifiable intangible assets			4,798,000
Other assets			25,377,000
Total identifiable assets acquired			632,872,000
Deposits			549,125,000
Other liabilities			5,397,000
Total liabilities assumed			554,522,000
Fair value of net identifiable assets acquired			78,350,000
Goodwill and intangible assets with indefinite lives			$ 141,923,000