Goodwill and Other Intangible Assets - Changes in Goodwill and Other Intangibles (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Finite-lived Intangible Assets [Roll Forward]
Core deposit premiums, beginning of period	$ 128,951
Amortization of intangibles	(16,306)	$ (15,915)	$ (13,494)
Core deposit premiums, end of period	112,645	128,951
Spirit of Texas Bancshares, Inc.
Finite-lived Intangible Assets [Roll Forward]
Core deposit premiums, beginning of period	36,500
Core deposit premiums, end of period		36,500
Core Deposit Premium
Finite-lived Intangible Assets [Roll Forward]
Core deposit premiums, beginning of period	116,016	93,862
Acquisitions	0	36,500
Amortization of intangibles	(14,672)	(14,346)	(12,100)
Core deposit premiums, end of period	101,344	116,016	93,862
Books of Business Intangible
Finite-lived Intangible Assets [Roll Forward]
Core deposit premiums, beginning of period	12,935	12,373
Acquisitions	0	2,131
Amortization of intangibles	(1,634)	(1,569)	(1,400)
Core deposit premiums, end of period	$ 11,301	$ 12,935	$ 12,373