Loans and Leases Portfolio (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Loan and lease portfolio
Loans and Leases	$ 6,209,857,000	$ 5,782,969,000	$ 6,095,387,000
Net gains related to sales of mortgage loans	700,000	3,300,000
Commercial
Loan and lease portfolio
Loans and Leases	2,572,163,000	2,326,423,000	2,528,433,000
Commercial and Industrial
Loan and lease portfolio
Loans and Leases	955,599,000		911,367,000
Commercial Mortgage
Loan and lease portfolio
Loans and Leases	1,284,181,000		1,247,510,000
Construction
Loan and lease portfolio
Loans and Leases	91,452,000		107,349,000
Lease Financing
Loan and lease portfolio
Loans and Leases	240,931,000		262,207,000
Consumer
Loan and lease portfolio
Loans and Leases	3,637,694,000	3,456,546,000	3,566,954,000
Residential Mortgage
Loan and lease portfolio
Loans and Leases	2,305,153,000		2,282,894,000
Home Equity
Loan and lease portfolio
Loans and Leases	797,341,000		773,385,000
Automobile
Loan and lease portfolio
Loans and Leases	273,553,000		255,986,000
Other
Loan and lease portfolio
Loans and Leases	$ 261,647,000		$ 254,689,000