Goodwill and Other Intangible Assets - Changes in Goodwill and Other Intangibles (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Finite-lived Intangible Assets [Roll Forward]
Core deposit premiums, beginning of period	$ 111,110
Amortization of intangibles	(13,494)	$ (13,495)	$ (11,805)
Total	106,235	111,110
Core deposit premiums, end of period	106,235	111,110
Core deposit intangible
Finite-lived Intangible Assets [Roll Forward]
Core deposit premiums, beginning of period	97,363	111,808
Acquisition of intangible asset	9,295	0
Disposition of intangible asset	(674)	(2,324)
Amortization of intangibles	(12,122)	(12,121)	(10,700)
Total	93,862	97,363	111,808
Core deposit premiums, end of period	93,862	97,363	111,808
Books of Business Intangible
Finite-lived Intangible Assets [Roll Forward]
Core deposit premiums, beginning of period	13,747	15,532
Disposition of intangible asset	0	(413)
Amortization of intangibles	(1,374)	(1,372)	(1,100)
Total	12,373	13,747	15,532
Core deposit premiums, end of period	12,373	$ 13,747	$ 15,532
Triumph
Finite-lived Intangible Assets [Roll Forward]
Total	5,100
Core deposit premiums, end of period	5,100
Landmark Bank
Finite-lived Intangible Assets [Roll Forward]
Total	4,200
Core deposit premiums, end of period	$ 4,200