Loans and Allowance for Credit Losses (Loans, Net of Unearned Income) (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022	Sep. 30, 2022
Accounts Notes And Loans Receivable [Line Items]
Total loans	$ 23,983,679	$ 23,114,046	$ 22,585,585
Residential Mortgages [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans	3,721,106	3,092,605	2,843,723
Consumer [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans	1,463,262	1,577,347	1,575,505
Commercial Real Estate - Income Producing [Member] | Total Commercial [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans	4,027,553	3,560,991	3,686,540
Construction and Land Development [Member] | Total Commercial [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans	1,614,846	1,703,592	1,541,257
Total Commercial And Industrial [Member] | Total Commercial [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans	13,156,912	13,179,511	12,938,560
Total Commercial And Industrial [Member] | Commercial Non-Real Estate [Member] | Total Commercial [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans	10,075,585	10,146,453	9,905,427
Total Commercial And Industrial [Member] | Commercial Real Estate - Owner Occupied [Member] | Total Commercial [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans	$ 3,081,327	$ 3,033,058	$ 3,033,133