Loans and Allowance for Credit Losses Summary of Delinquency and Non-Performing Status by Portfolio Segment (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011
Loans, net of unearned income	$ 12,144,604		$ 11,968,970
Period for Which Change in Loans Evaluated Individually For Impairment	90
Minimum [Member]
Financing Receivable, Recorded Investment, Days Outstanding	30
Maximum [Member]
Financing Receivable, Recorded Investment, Days Outstanding	89
Real Estate - Home Equity [Member]
Loans, net of unearned income	1,632,390		1,624,562
Real-estate - residential mortgage
Loans, net of unearned income	1,256,991		1,097,192
Construction other [Member]
Loans, net of unearned income	69,216		53,127
Consumer - Direct [Member]
Loans, net of unearned income	165,937		164,369
Consumer - Indirect [Member]
Loans, net of unearned income	143,283		153,732
Consumer
Loans, net of unearned income	309,220		318,101
Leasing and Other and Overdrafts [Member]
Loans, net of unearned income	85,394		71,706
Commercial Loans, Commerical Mortgages, Constructions Loans [Member]
Loans, net of unearned income	3,353,211		3,164,688
Loans and Leases Receivable, Ratio of Nonperforming Loans to All Loans	100.00%		100.00%
Performing [Member] | Real Estate - Home Equity [Member]
Loans, net of unearned income	1,604,226		1,601,722
Performing [Member] | Real-estate - residential mortgage
Loans, net of unearned income	1,190,432		1,043,733
Performing [Member] | Construction other [Member]
Loans, net of unearned income	67,447		49,593
Performing [Member] | Consumer - Direct [Member]
Loans, net of unearned income	157,287		157,157
Performing [Member] | Consumer - Indirect [Member]
Loans, net of unearned income	140,868		151,112
Performing [Member] | Consumer
Loans, net of unearned income	298,155		308,269
Performing [Member] | Leasing and Other and Overdrafts [Member]
Loans, net of unearned income	84,664		70,550
Performing [Member] | Commercial Loans, Commerical Mortgages, Constructions Loans [Member]
Loans, net of unearned income	3,244,924		3,073,867
Loans and Leases Receivable, Ratio of Nonperforming Loans to All Loans	96.70%		97.10%
Delinquent [Member] | Real Estate - Home Equity [Member]
Loans, net of unearned income	12,645	[1]	11,633	[1]
Delinquent [Member] | Real-estate - residential mortgage
Loans, net of unearned income	32,123	[1]	37,123	[1]
Delinquent [Member] | Construction other [Member]
Loans, net of unearned income	865	[1]	2,341	[1]
Delinquent [Member] | Consumer - Direct [Member]
Loans, net of unearned income	3,795	[1]	4,011	[1]
Delinquent [Member] | Consumer - Indirect [Member]
Loans, net of unearned income	2,270	[1]	2,437	[1]
Delinquent [Member] | Consumer
Loans, net of unearned income	6,065	[1]	6,448	[1]
Delinquent [Member] | Leasing and Other and Overdrafts [Member]
Loans, net of unearned income	711	[1]	1,049	[1]
Delinquent [Member] | Commercial Loans, Commerical Mortgages, Constructions Loans [Member]
Loans, net of unearned income	52,409	[1]	58,594	[1]
Loans and Leases Receivable, Ratio of Nonperforming Loans to All Loans	1.60%		1.90%
Nonperforming [Member] | Real Estate - Home Equity [Member]
Loans, net of unearned income	15,519	[2]	11,207	[2]
Nonperforming [Member] | Real-estate - residential mortgage
Loans, net of unearned income	34,436	[2]	16,336	[2]
Nonperforming [Member] | Construction other [Member]
Loans, net of unearned income	904	[2]	1,193	[2]
Nonperforming [Member] | Consumer - Direct [Member]
Loans, net of unearned income	4,855	[2]	3,201	[2]
Nonperforming [Member] | Consumer - Indirect [Member]
Loans, net of unearned income	145	[2]	183	[2]
Nonperforming [Member] | Consumer
Loans, net of unearned income	5,000	[2]	3,384	[2]
Nonperforming [Member] | Leasing and Other and Overdrafts [Member]
Loans, net of unearned income	19	[2]	107	[2]
Nonperforming [Member] | Commercial Loans, Commerical Mortgages, Constructions Loans [Member]
Loans, net of unearned income	$ 55,878	[2]	$ 32,227	[2]
Loans and Leases Receivable, Ratio of Nonperforming Loans to All Loans	1.70%		1.00%

[1] 1)Includes all accruing loans 30 days to 89 days past due

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