Goodwill and Other Intangible Assets - Changes in Goodwill and Other Intangibles (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Finite-lived Intangible Assets [Roll Forward]
Core deposit premiums, beginning of period	$ 106,235
Amortization of intangibles	(15,915)	$ (13,494)	$ (13,495)
Core deposit premiums, end of period	128,951	106,235
Spirit of Texas Bancshares, Inc.
Finite-lived Intangible Assets [Roll Forward]
Core deposit premiums, end of period	36,500
Triumph Bancshares Inc
Finite-lived Intangible Assets [Roll Forward]
Core deposit premiums, beginning of period	5,100
Core deposit premiums, end of period		5,100
Landmark Community Bank
Finite-lived Intangible Assets [Roll Forward]
Core deposit premiums, beginning of period	4,200
Core deposit premiums, end of period		4,200
Core Deposit Premium
Finite-lived Intangible Assets [Roll Forward]
Core deposit premiums, beginning of period	93,862	97,363
Acquisitions	36,500	9,295
Disposition of intangible asset	0	(674)
Amortization of intangibles	(14,346)	(12,122)	(12,100)
Core deposit premiums, end of period	116,016	93,862	97,363
Books of Business Intangible
Finite-lived Intangible Assets [Roll Forward]
Core deposit premiums, beginning of period	12,373	13,747
Acquisitions	2,131	0
Amortization of intangibles	(1,569)	(1,374)	(1,400)
Core deposit premiums, end of period	$ 12,935	$ 12,373	$ 13,747