Loans (Schedule Of Loans By Portfolio Segment) (Details) - USD ($) $ in Thousands	Jun. 30, 2018		Mar. 31, 2018	Dec. 31, 2017		Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	$ 27,701,740	[1]		$ 27,658,929	[1]	$ 19,989,319
Allowance for loan losses	185,462		$ 187,194	189,555		197,257	$ 201,968	$ 202,068
Total net loans	27,516,278			27,469,374
Commercial, financial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	16,438,745			16,057,273		12,598,219
Allowance for loan losses	96,834		100,238	98,211		92,379	93,107	89,398
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	4,136,356			4,214,695		2,211,996
Allowance for loan losses	33,832		29,057	28,427		30,470	30,888	33,852
Consumer real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	6,222,611			6,367,755		4,417,459
Allowance for loan losses	31,769		32,750	37,371		46,069	49,680	50,357
Permanent mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	354,916			399,307		408,095
Allowance for loan losses	14,078		15,435	15,565		16,398	15,893	16,289
Credit card & other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	549,112			619,899		353,550
Allowance for loan losses	8,949		$ 9,714	9,981		$ 11,941	$ 12,400	$ 12,172
Restricted real estate loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	$ 18,900			$ 24,200

[1] June 30, 2018 and December 31, 2017 include $21.4 million and $22.7 million, respectively, of held-to-maturity consumer mortgage loans secured by residential real estate in process of foreclosure.