Loans and Leases and the Allowance for Loan and Lease Losses (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011
Loan and lease portfolio
Total Loans and Leases	$ 5,782,304	$ 5,538,304	$ 5,348,472
Commercial
Loan and lease portfolio
Total Loans and Leases	2,227,323	2,166,017	2,094,163
Commercial and Industrial
Loan and lease portfolio
Total Loans and Leases	808,621	817,170
Commercial Mortgage
Loan and lease portfolio
Total Loans and Leases	1,039,556	938,250
Construction
Loan and lease portfolio
Total Loans and Leases	101,818	98,669
Lease Financing
Loan and lease portfolio
Total Loans and Leases	277,328	311,928
Consumer
Loan and lease portfolio
Total Loans and Leases	3,554,981	3,372,287	3,254,309
Residential Mortgage
Loan and lease portfolio
Total Loans and Leases	2,392,871	2,215,892
Home Equity
Loan and lease portfolio
Total Loans and Leases	770,284	780,691
Automobile
Loan and lease portfolio
Total Loans and Leases	200,788	192,506
Other Consumer
Loan and lease portfolio
Total Loans and Leases	$ 191,038	$ 183,198