Loans and Leases and the Allowance for Loan and Lease Losses (Loans and Leases Portfolio and Narrative) (Details 1) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Loan and lease portfolio
Loans and Leases	$ 10,759,129	$ 10,053,323	$ 10,759,129	$ 10,053,323	$ 10,448,774
Net Gains Related to Sales of Residential Mortgage Loans	1,100	500	1,600	800
Commercial
Loan and lease portfolio
Loans and Leases	4,102,316	3,816,272	4,102,316	3,816,272	3,979,792
Commercial | Commercial and Industrial
Loan and lease portfolio
Loans and Leases	1,408,729		1,408,729		1,331,149
Commercial | Commercial Mortgage
Loan and lease portfolio
Loans and Leases	2,411,289		2,411,289		2,302,356
Commercial | Construction
Loan and lease portfolio
Loans and Leases	119,228		119,228		170,061
Commercial | Lease Financing
Loan and lease portfolio
Loans and Leases	163,070		163,070		176,226
Consumer
Loan and lease portfolio
Loans and Leases	6,656,813	$ 6,237,051	6,656,813	$ 6,237,051	6,468,982
Consumer | Residential Mortgage
Loan and lease portfolio
Loans and Leases	3,785,006		3,785,006		3,673,796
Consumer | Home Equity
Loan and lease portfolio
Loans and Leases	1,694,577		1,694,577		1,681,442
Consumer | Automobile
Loan and lease portfolio
Loans and Leases	703,523		703,523		658,133
Consumer | Other
Loan and lease portfolio
Loans and Leases	$ 473,707		$ 473,707		$ 455,611