Loans and Leases and the Allowance for Loan and Lease Losses (Details 3) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2011	Dec. 31, 2010
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	$ 5,351,473	$ 5,335,792
Commercial | Pass
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	1,924,719	1,864,121
Commercial and Industrial | Pass
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	776,973	720,618
Commercial Mortgage | Pass
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	796,615	775,938
Construction | Pass
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	63,255	61,598
Lease Financing | Pass
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	287,876	305,967
Consumer | Pass
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	3,232,356	3,244,530
Residential Mortgage | Pass
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	2,101,968	2,059,012
Home Equity | Pass
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	780,280	804,158
Automobile | Pass
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	191,572	208,598
Other Consumer | Pass
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	158,536	172,762
Commercial | Special Mention
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	64,071	78,893
Commercial and Industrial | Special Mention
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	11,742	18,096
Commercial Mortgage | Special Mention
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	26,902	32,055
Construction | Special Mention
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	592	1,975
Lease Financing | Special Mention
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	24,835	26,767
Commercial | Classified
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	97,613	108,317
Commercial and Industrial | Classified
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	27,197	33,910
Commercial Mortgage | Classified
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	48,766	55,392
Construction | Classified
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	17,585	16,752
Lease Financing | Classified
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	4,065	2,263
Consumer | Classified
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	32,714	39,931
Residential Mortgage | Classified
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	28,367	35,177
Home Equity | Classified
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	3,302	3,321
Automobile | Classified
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	167	410
Other Consumer | Classified
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	878	1,023
Classified
Recorded investment in loans and leases by class and by credit quality indicator
Maximum current loan-to-value ratio for residential mortgage and home equity loans to be considered as pass (as a percent)	60.00%
Commercial
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	2,086,403	2,051,331
Commercial and Industrial
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	815,912	772,624
Commercial Mortgage
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	872,283	863,385
Construction
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	81,432	80,325
Lease Financing
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	316,776	334,997
Consumer
Recorded investment in loans and leases by class and by credit quality indicator
Number of days past due for loans and leases in classified credit quality indicator (in days)	90
Total Recorded Investment in Loans and Leases	3,265,070	3,284,461
Residential Mortgage
Recorded investment in loans and leases by class and by credit quality indicator
Number of days past due for loans and leases in classified credit quality indicator (in days)	90
Total Recorded Investment in Loans and Leases	2,130,335	2,094,189
Number of months up to which residential and home equity loans may be considered classified, even if they are current as to principal and interest (in months)	6
Home Equity
Recorded investment in loans and leases by class and by credit quality indicator
Number of days past due for loans and leases in classified credit quality indicator (in days)	90
Total Recorded Investment in Loans and Leases	783,582	807,479
Automobile
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	191,739	209,008
Other Consumer
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	$ 159,414	$ 173,785