Loans and Leases and the Allowance for Loan and Lease Losses (Details 3) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2011 contract day	Dec. 31, 2010
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	$ 5,348,472	$ 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	1,922,700	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	742,444	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	845,563	775,938
Construction | Pass
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	52,570	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	282,123	305,967
Consumer | Pass
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	3,220,628	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	2,102,296	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	770,603	804,158
Automobile | Pass
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	191,359	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	156,370	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	81,185	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	26,170	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	28,253	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	579	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	26,183	26,767
Commercial | Classified
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	90,278	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	21,680	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	48,259	55,392
Construction | Classified
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	16,486	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	3,853	2,263
Consumer | Classified
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	33,681	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	28,293	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	4,502	3,321
Automobile | Classified
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	138	410
Other Consumer | Classified
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	748	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	2,094,163	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	790,294	772,624
Commercial Mortgage
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	922,075	863,385
Construction
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	69,635	80,325
Lease Financing
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	312,159	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	3,254,309	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
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
Total Recorded Investment in Loans and Leases	2,130,589	2,094,189
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	775,105	807,479
Automobile
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	191,497	209,008
Other Consumer
Recorded investment in loans and leases by class and by credit quality indicator
Total Recorded Investment in Loans and Leases	$ 157,118	$ 173,785