Loans - Schedule Of Loans By Portfolio Segment (Details) - USD ($) $ in Thousands	Jun. 30, 2020		Mar. 31, 2020	Dec. 31, 2019		Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	$ 32,708,937	[1]		$ 31,061,111	[1]	$ 29,712,810
Allowance for loan losses	537,881		$ 444,490	200,307		192,749	$ 184,911	$ 180,424
Total net loans	32,171,056			30,860,804
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses				158,598
Commercial | Commercial, financial, and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	21,393,893			20,051,091		19,054,269
Allowance for loan losses	318,722		254,516	122,486		116,096	103,713	98,947
Commercial | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	4,813,341			4,337,017		3,861,031
Allowance for loan losses	57,285		47,625	36,112		32,953	34,382	31,311
Consumer | Consumer real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	6,052,393			6,177,139		6,303,134
Allowance for loan losses	143,757		123,022	28,443		31,532	34,154	37,439
Consumer | Credit Card and Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	449,310			495,864		494,376
Allowance for loan losses	$ 18,117		$ 19,327	$ 13,266		$ 12,168	$ 12,662	$ 12,727

[1] June 30, 2020 and December 31, 2019 include $16.9 million and $18.8 million, respectively, of held-to-maturity consumer mortgage loans secured by residential real estate in process of foreclosure.