Loans (Schedule Of Loans By Portfolio Segment) (Details) - USD ($) $ in Thousands	Jun. 30, 2017		Mar. 31, 2017	Dec. 31, 2016		Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	$ 19,989,319	[1]		$ 19,589,520	[1]	$ 18,589,337
Allowance for loan losses	197,257		$ 201,968	202,068		199,807	$ 204,034	$ 210,242
Total net loans	19,792,062			19,387,452
Commercial Financial And Industrial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	12,598,219			12,148,087		11,179,445
Allowance for loan losses	92,379		93,107	89,398		80,972	80,887	73,637
Commercial Real Estate Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	2,211,996			2,135,523		1,969,412
Allowance for loan losses	30,470		30,888	33,852		30,264	25,626	25,159
Consumer Real Estate Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	4,417,459	[2]		4,523,752	[2]	4,640,779
Allowance for loan losses	46,069		49,680	50,357		59,081	67,321	80,614
Permanent Mortgage Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	408,095			423,125		439,014
Allowance for loan losses	16,398		15,893	16,289		17,600	18,754	18,947
Credit Card And Other Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	353,550			359,033		360,687
Allowance for loan losses	11,941		$ 12,400	12,172		$ 11,890	$ 11,446	$ 11,885
Restricted And Secured Consumer Real Estate Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	$ 28,800			$ 35,900

[1] June 30, 2017 and December 31, 2016 include $28.8 million and $28.5 million, respectively, of held-to-maturity consumer mortgage loans secured by residential real estate properties in process of foreclosure.

[2] Balances as of June 30, 2017 and December 31, 2016, include $28.8 million and $35.9 million of restricted real estate loans, respectively. See Note 13—Variable Interest Entities for additional information.