Loans and Allowance for Credit Losses - Financing Receivables Past Due (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Financing Receivable, Past Due [Line Items]
Loans	$ 31,943,284	$ 29,041,605
Commercial real estate - owner occupied
Financing Receivable, Past Due [Line Items]
Loans	3,944,616	3,587,257
Commercial real estate - non-owner occupied
Financing Receivable, Past Due [Line Items]
Loans	7,447,610	6,542,619
Consumer real estate – mortgage
Financing Receivable, Past Due [Line Items]
Loans	4,768,780	4,435,046
Construction and land development
Financing Receivable, Past Due [Line Items]
Loans	3,942,143	3,679,498
Commercial and industrial
Financing Receivable, Past Due [Line Items]
Loans	11,307,611	10,241,362
Consumer and other
Financing Receivable, Past Due [Line Items]
Loans	532,524	555,823
30-59 days past due
Financing Receivable, Past Due [Line Items]
Loans	25,425	35,840
30-59 days past due | Commercial real estate - owner occupied
Financing Receivable, Past Due [Line Items]
Loans	3,218	2,112
30-59 days past due | Commercial real estate - non-owner occupied
Financing Receivable, Past Due [Line Items]
Loans	214	359
30-59 days past due | Consumer real estate – mortgage
Financing Receivable, Past Due [Line Items]
Loans	3,361	13,635
30-59 days past due | Construction and land development
Financing Receivable, Past Due [Line Items]
Loans	154	221
30-59 days past due | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Loans	14,889	15,457
30-59 days past due | Consumer and other
Financing Receivable, Past Due [Line Items]
Loans	3,589	4,056
60-89 days past due
Financing Receivable, Past Due [Line Items]
Loans	23,783	16,249
60-89 days past due | Commercial real estate - owner occupied
Financing Receivable, Past Due [Line Items]
Loans	202	615
60-89 days past due | Commercial real estate - non-owner occupied
Financing Receivable, Past Due [Line Items]
Loans	0	48
60-89 days past due | Consumer real estate – mortgage
Financing Receivable, Past Due [Line Items]
Loans	16,926	83
60-89 days past due | Construction and land development
Financing Receivable, Past Due [Line Items]
Loans	227	102
60-89 days past due | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Loans	4,521	13,713
60-89 days past due | Consumer and other
Financing Receivable, Past Due [Line Items]
Loans	1,907	1,688
90 days or more past due
Financing Receivable, Past Due [Line Items]
Loans	34,240	22,218
90 days or more past due | Commercial real estate - owner occupied
Financing Receivable, Past Due [Line Items]
Loans	4,947	1,139
90 days or more past due | Commercial real estate - non-owner occupied
Financing Receivable, Past Due [Line Items]
Loans	153	1,681
90 days or more past due | Consumer real estate – mortgage
Financing Receivable, Past Due [Line Items]
Loans	9,767	9,094
90 days or more past due | Construction and land development
Financing Receivable, Past Due [Line Items]
Loans	0	130
90 days or more past due | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Loans	18,012	9,428
90 days or more past due | Consumer and other
Financing Receivable, Past Due [Line Items]
Loans	1,361	746
Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans	83,448	74,307
Financial Asset, Past Due | Commercial real estate - owner occupied
Financing Receivable, Past Due [Line Items]
Loans	8,367	3,866
Financial Asset, Past Due | Commercial real estate - non-owner occupied
Financing Receivable, Past Due [Line Items]
Loans	367	2,088
Financial Asset, Past Due | Consumer real estate – mortgage
Financing Receivable, Past Due [Line Items]
Loans	30,054	22,812
Financial Asset, Past Due | Construction and land development
Financing Receivable, Past Due [Line Items]
Loans	381	453
Financial Asset, Past Due | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Loans	37,422	38,598
Financial Asset, Past Due | Consumer and other
Financing Receivable, Past Due [Line Items]
Loans	6,857	6,490
Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Loans	31,859,836	28,967,298
Financial Asset, Not Past Due | Commercial real estate - owner occupied
Financing Receivable, Past Due [Line Items]
Loans	3,936,249	3,583,391
Financial Asset, Not Past Due | Commercial real estate - non-owner occupied
Financing Receivable, Past Due [Line Items]
Loans	7,447,243	6,540,531
Financial Asset, Not Past Due | Consumer real estate – mortgage
Financing Receivable, Past Due [Line Items]
Loans	4,738,726	4,412,234
Financial Asset, Not Past Due | Construction and land development
Financing Receivable, Past Due [Line Items]
Loans	3,941,762	3,679,045
Financial Asset, Not Past Due | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Loans	11,270,189	10,202,764
Financial Asset, Not Past Due | Consumer and other
Financing Receivable, Past Due [Line Items]
Loans	$ 525,667	$ 549,333