Loans and Allowance for Credit Losses Summary of Delinquency and Non-Performing Status by Portfolio Segment (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012		Dec. 31, 2011
Loans, gross of unearned income	$ 11,964,454		$ 11,975,964
Real Estate, Home Equity, Construction, Other, Consumer and Leasing [Member]
Loans, gross of unearned income	3,213,765		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	3,124,935		3,073,867
Percentage Of Total	97.20%		97.10%
Real Estate, Home Equity, Construction, Other, Consumer and Leasing [Member] | Delinquent [Member]
Loans, gross of unearned income	50,464	[1]	58,594	[1]
Percentage Of Total	1.60%	[1]	1.90%	[1]
Real Estate, Home Equity, Construction, Other, Consumer and Leasing [Member] | Non-performing [Member]
Loans, gross of unearned income	38,366	[2]	32,227	[2]
Percentage Of Total	1.20%	[2]	1.00%	[2]
Real-estate - home equity [Member]
Loans, gross of unearned income	1,601,880		1,624,562
Real-estate - home equity [Member] | Performing [Member]
Loans, gross of unearned income	1,579,174		1,601,722
Real-estate - home equity [Member] | Delinquent [Member]
Loans, gross of unearned income	11,792	[1]	11,633	[1]
Real-estate - home equity [Member] | Non-performing [Member]
Loans, gross of unearned income	10,914	[2]	11,207	[2]
Real-estate - residential mortgage [Member]
Loans, gross of unearned income	1,176,947		1,097,192
Real-estate - residential mortgage [Member] | Performing [Member]
Loans, gross of unearned income	1,121,395		1,043,733
Real-estate - residential mortgage [Member] | Delinquent [Member]
Loans, gross of unearned income	32,536	[1]	37,123	[1]
Real-estate - residential mortgage [Member] | Non-performing [Member]
Loans, gross of unearned income	23,016	[2]	16,336	[2]
Construction other [Member]
Loans, gross of unearned income	56,521		53,127
Construction other [Member] | Performing [Member]
Loans, gross of unearned income	54,424		49,593
Construction other [Member] | Delinquent [Member]
Loans, gross of unearned income	843	[1]	2,341	[1]
Construction other [Member] | Non-performing [Member]
Loans, gross of unearned income	1,254	[2]	1,193	[2]
Total Consumer
Loans, gross of unearned income	308,495		318,101
Total Consumer | Performing [Member]
Loans, gross of unearned income	300,845		308,269
Total Consumer | Delinquent [Member]
Loans, gross of unearned income	4,816	[1]	6,448	[1]
Total Consumer | Non-performing [Member]
Loans, gross of unearned income	2,834	[2]	3,384	[2]
Consumer - direct [Member]
Loans, gross of unearned income	32,441		35,438
Consumer - direct [Member] | Performing [Member]
Loans, gross of unearned income	31,529		34,263
Consumer - direct [Member] | Delinquent [Member]
Loans, gross of unearned income	505	[1]	657	[1]
Consumer - direct [Member] | Non-performing [Member]
Loans, gross of unearned income	407	[2]	518	[2]
Consumer - Indirect [Member]
Loans, gross of unearned income	148,397		153,732
Consumer - Indirect [Member] | Performing [Member]
Loans, gross of unearned income	146,798		151,112
Consumer - Indirect [Member] | Delinquent [Member]
Loans, gross of unearned income	1,518	[1]	2,437	[1]
Consumer - Indirect [Member] | Non-performing [Member]
Loans, gross of unearned income	81	[2]	183	[2]
Consumer Other [Member]
Loans, gross of unearned income	127,657		128,931
Consumer Other [Member] | Performing [Member]
Loans, gross of unearned income	122,518		122,894
Consumer Other [Member] | Delinquent [Member]
Loans, gross of unearned income	2,793	[1]	3,354	[1]
Consumer Other [Member] | Non-performing [Member]
Loans, gross of unearned income	2,346	[2]	2,683	[2]
Leasing and other and overdrafts [Member]
Loans, gross of unearned income	69,922		71,706
Leasing and other and overdrafts [Member] | Performing [Member]
Loans, gross of unearned income	69,097		70,550
Leasing and other and overdrafts [Member] | Delinquent [Member]
Loans, gross of unearned income	477	[1]	1,049	[1]
Leasing and other and overdrafts [Member] | Non-performing [Member]
Loans, gross of unearned income	$ 348	[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.