Loans and Allowance for Credit Losses Summary of Delinquency and Non-Performing Status by Portfolio Segment (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012		Dec. 31, 2011
Loans, gross of unearned income	$ 11,940,005		$ 11,975,964
Real Estate, Home Equity, Construction, Other, Consumer and Leasing [Member]
Loans, gross of unearned income	3,261,160		3,164,688
Percentage Of Total	100.00%		100.00%
Real Estate, Home Equity, Construction, Other, Consumer and Leasing [Member] | Performing [Member]
Loans, gross of unearned income	3,161,412		3,073,867
Percentage Of Total	96.90%		97.10%
Real Estate, Home Equity, Construction, Other, Consumer and Leasing [Member] | Delinquent [Member]
Loans, gross of unearned income	57,415	[1]	58,594	[1]
Percentage Of Total	1.80%	[1]	1.90%	[1]
Real Estate, Home Equity, Construction, Other, Consumer and Leasing [Member] | Non-performing [Member]
Loans, gross of unearned income	42,333	[2]	32,227	[2]
Percentage Of Total	1.30%	[2]	1.00%	[2]
Real-estate - home equity [Member]
Loans, gross of unearned income	1,603,456		1,624,562
Real-estate - home equity [Member] | Performing [Member]
Loans, gross of unearned income	1,577,256		1,601,722
Real-estate - home equity [Member] | Delinquent [Member]
Loans, gross of unearned income	13,557	[1]	11,633	[1]
Real-estate - home equity [Member] | Non-performing [Member]
Loans, gross of unearned income	12,643	[2]	11,207	[2]
Real-estate - residential mortgage [Member]
Loans, gross of unearned income	1,213,831		1,097,192
Real-estate - residential mortgage [Member] | Performing [Member]
Loans, gross of unearned income	1,156,610		1,043,733
Real-estate - residential mortgage [Member] | Delinquent [Member]
Loans, gross of unearned income	32,311	[1]	37,123	[1]
Real-estate - residential mortgage [Member] | Non-performing [Member]
Loans, gross of unearned income	24,910	[2]	16,336	[2]
Construction other [Member]
Loans, gross of unearned income	65,872		53,127
Construction other [Member] | Performing [Member]
Loans, gross of unearned income	60,571		49,593
Construction other [Member] | Delinquent [Member]
Loans, gross of unearned income	4,564	[1]	2,341	[1]
Construction other [Member] | Non-performing [Member]
Loans, gross of unearned income	737	[2]	1,193	[2]
Total Consumer
Loans, gross of unearned income	301,182		318,101
Total Consumer | Performing [Member]
Loans, gross of unearned income	291,021		308,269
Total Consumer | Delinquent [Member]
Loans, gross of unearned income	6,218	[1]	6,448	[1]
Total Consumer | Non-performing [Member]
Loans, gross of unearned income	3,943	[2]	3,384	[2]
Consumer - direct [Member]
Loans, gross of unearned income	153,950		164,369
Consumer - direct [Member] | Performing [Member]
Loans, gross of unearned income	146,351		157,157
Consumer - direct [Member] | Delinquent [Member]
Loans, gross of unearned income	3,908	[1]	4,011	[1]
Consumer - direct [Member] | Non-performing [Member]
Loans, gross of unearned income	3,691	[2]	3,201	[2]
Consumer - Indirect [Member]
Loans, gross of unearned income	147,232		153,732
Consumer - Indirect [Member] | Performing [Member]
Loans, gross of unearned income	144,670		151,112
Consumer - Indirect [Member] | Delinquent [Member]
Loans, gross of unearned income	2,310	[1]	2,437	[1]
Consumer - Indirect [Member] | Non-performing [Member]
Loans, gross of unearned income	252	[2]	183	[2]
Leasing and other and overdrafts [Member]
Loans, gross of unearned income	76,819		71,706
Leasing and other and overdrafts [Member] | Performing [Member]
Loans, gross of unearned income	75,954		70,550
Leasing and other and overdrafts [Member] | Delinquent [Member]
Loans, gross of unearned income	765	[1]	1,049	[1]
Leasing and other and overdrafts [Member] | Non-performing [Member]
Loans, gross of unearned income	$ 100	[2]	$ 107	[2]

[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.