Loans and Allowance for Credit Losses (Loans, at Amortized Cost Basis) (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023	Sep. 30, 2023
Accounts Notes And Loans Receivable [Line Items]
Total loans	$ 23,455,587	$ 23,921,917	$ 23,983,679
Residential Mortgages [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans	3,988,309	3,886,072	3,721,106
Consumer [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans	1,370,520	1,446,764	1,463,262
Commercial Real Estate - Income Producing [Member] | Total Commercial [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans	3,988,661	3,986,943	4,027,553
Construction and Land Development [Member] | Total Commercial [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans	1,423,615	1,551,091	1,614,846
Total Commercial And Industrial [Member] | Total Commercial [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans	12,684,482	13,051,047	13,156,912
Total Commercial And Industrial [Member] | Commercial Non-Real Estate [Member] | Total Commercial [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans	9,588,309	9,957,284	10,075,585
Total Commercial And Industrial [Member] | Commercial Real Estate - Owner Occupied [Member] | Total Commercial [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans	$ 3,096,173	$ 3,093,763	$ 3,081,327