Goodwill and Other Intangible Assets - Changes in Goodwill and Other Intangibles (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Finite-lived Intangible Assets [Roll Forward]
Core deposit premiums, beginning of period	$ 106,235
Amortization of intangibles	(3,486)	$ (3,344)
Total	102,748		$ 106,235
Core deposit premiums, end of period	102,748		106,235
Triumph
Finite-lived Intangible Assets [Roll Forward]
Core deposit premiums, beginning of period	5,100
Total			5,100
Core deposit premiums, end of period			5,100
Landmark Bank
Finite-lived Intangible Assets [Roll Forward]
Core deposit premiums, beginning of period	4,200
Total			4,200
Core deposit premiums, end of period			4,200
Core deposit intangible
Finite-lived Intangible Assets [Roll Forward]
Core deposit premiums, beginning of period	93,862	97,363	97,363
Acquisitions	0		9,295
Disposition of intangible asset	0		(674)
Amortization of intangibles	(3,144)		(12,122)
Total	90,718		93,862
Core deposit premiums, end of period	90,718		93,862
Books of Business Intangible
Finite-lived Intangible Assets [Roll Forward]
Core deposit premiums, beginning of period	12,373	$ 13,747	13,747
Amortization of intangibles	(343)		(1,374)
Total	12,030		12,373
Core deposit premiums, end of period	$ 12,030		$ 12,373