Loans and Allowance for Credit Losses Summary of Delinquency and Non-Performing Status by Portfolio Segment (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2011		Dec. 31, 2010
Loans, net of unearned income	$ 11,895,655		$ 11,933,307
Period for Which Change in Loans Evaluated Individually For Impairment	90
Real-estate - home equity
Loans, net of unearned income	1,630,880		1,641,777
Real-estate - home equity | Performing Financing Receivable [Member]
Loans, net of unearned income	1,606,705		1,619,684
Real-estate - home equity | Delinquent [Member]
Loans, net of unearned income	12,078	[1]	11,905	[1]
Real-estate - home equity | Nonperforming Financing Receivable [Member]
Loans, net of unearned income	12,097	[2]	10,188	[2]
Real-estate - residential mortgage
Loans, net of unearned income	1,041,463		995,990
Real-estate - residential mortgage | Performing Financing Receivable [Member]
Loans, net of unearned income	961,912		909,247
Real-estate - residential mortgage | Delinquent [Member]
Loans, net of unearned income	31,465	[1]	36,331	[1]
Real-estate - residential mortgage | Nonperforming Financing Receivable [Member]
Loans, net of unearned income	48,086	[2]	50,412	[2]
Construction other [Member]
Loans, net of unearned income	54,399		63,849
Performing Financing Receivable [Member] | Construction other [Member]
Loans, net of unearned income	49,580		60,956
Delinquent [Member] | Construction other [Member]
Loans, net of unearned income	3,431	[1]	0	[1]
Nonperforming Financing Receivable [Member] | Construction other [Member]
Loans, net of unearned income	1,388	[2]	2,893	[2]
Consumer - Direct [Member]
Loans, net of unearned income	37,354		47,089
Consumer - Direct [Member] | Performing Financing Receivable [Member]
Loans, net of unearned income	36,326		45,942
Consumer - Direct [Member] | Delinquent [Member]
Loans, net of unearned income	681	[1]	935	[1]
Consumer - Direct [Member] | Nonperforming Financing Receivable [Member]
Loans, net of unearned income	347	[2]	212	[2]
Consumer - Indirect [Member]
Loans, net of unearned income	157,765		169,096
Consumer - Indirect [Member] | Performing Financing Receivable [Member]
Loans, net of unearned income	155,555		166,531
Consumer - Indirect [Member] | Delinquent [Member]
Loans, net of unearned income	2,085	[1]	2,275	[1]
Consumer - Indirect [Member] | Nonperforming Financing Receivable [Member]
Loans, net of unearned income	125	[2]	290	[2]
Consumer Other [Member]
Loans, net of unearned income	131,935		133,976
Consumer Other [Member] | Performing Financing Receivable [Member]
Loans, net of unearned income	126,594		129,911
Consumer Other [Member] | Delinquent [Member]
Loans, net of unearned income	3,199	[1]	2,413	[1]
Consumer Other [Member] | Nonperforming Financing Receivable [Member]
Loans, net of unearned income	2,142	[2]	1,652	[2]
Consumer
Loans, net of unearned income	327,054		350,161
Consumer | Performing Financing Receivable [Member]
Loans, net of unearned income	318,475		342,384
Consumer | Delinquent [Member]
Loans, net of unearned income	5,965	[1]	5,623	[1]
Consumer | Nonperforming Financing Receivable [Member]
Loans, net of unearned income	2,614	[2]	2,154	[2]
Leasing and Other and Overdrafts [Member]
Loans, net of unearned income	66,541		63,830
Leasing and Other and Overdrafts [Member] | Performing Financing Receivable [Member]
Loans, net of unearned income	65,666		63,087
Leasing and Other and Overdrafts [Member] | Delinquent [Member]
Loans, net of unearned income	763	[1]	516	[1]
Leasing and Other and Overdrafts [Member] | Nonperforming Financing Receivable [Member]
Loans, net of unearned income	112	[2]	227	[2]
Commercial Loans, Commerical Mortgages, Constructions Loans [Member]
Loans, net of unearned income	3,120,337		3,115,607
Performing Financing Receivable [Member]
Loans, net of unearned income	3,002,338		2,995,358
Delinquent [Member]
Loans, net of unearned income	53,702	[1]	54,375	[1]
Nonperforming Financing Receivable [Member]
Loans, net of unearned income	$ 64,297	[2]	$ 65,874	[2]
Minimum [Member]
Financing Receivable, Recorded Investment, Days Outstanding	31
Maximum [Member]
Financing Receivable, Recorded Investment, Days Outstanding	89

[1] Includes all accruing loans 31 days to 89 days past due.

[2] Includes all accruing loans 90 days or more past due and all non-accrual loans.