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		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Loan and lease portfolio
Loans and Leases	$ 10,881,298	$ 10,231,062	$ 10,881,298	$ 10,231,062	$ 10,448,774
Net Gains Related to Sales of Residential Mortgage Loans	2,500	400	4,100	1,100
Commercial
Loan and lease portfolio
Loans and Leases	4,156,733	3,900,308	4,156,733	3,900,308	3,979,792
Commercial | Commercial and Industrial
Loan and lease portfolio
Loans and Leases	1,361,011		1,361,011		1,331,149
Commercial | Commercial Mortgage
Loan and lease portfolio
Loans and Leases	2,477,296		2,477,296		2,302,356
Commercial | Construction
Loan and lease portfolio
Loans and Leases	154,754		154,754		170,061
Commercial | Lease Financing
Loan and lease portfolio
Loans and Leases	163,672		163,672		176,226
Consumer
Loan and lease portfolio
Loans and Leases	6,724,565	$ 6,330,754	6,724,565	$ 6,330,754	6,468,982
Consumer | Residential Mortgage
Loan and lease portfolio
Loans and Leases	3,846,511		3,846,511		3,673,796
Consumer | Home Equity
Loan and lease portfolio
Loans and Leases	1,681,951		1,681,951		1,681,442
Consumer | Automobile
Loan and lease portfolio
Loans and Leases	713,424		713,424		658,133
Consumer | Other
Loan and lease portfolio
Loans and Leases	$ 482,679		$ 482,679		$ 455,611