Loan and Lease Financings (Details 3) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Loan and Lease Financings
Recorded investment in loans and leases	$ 4,527,678	$ 4,188,071
Residential real estate and consumer loans
Loan and Lease Financings
Recorded investment in loans and leases	654,268	651,744
Residential real estate and home equity
Loan and Lease Financings
Recorded investment in loans and leases	526,122	521,931
Consumer
Loan and Lease Financings
Recorded investment in loans and leases	128,146	129,813
Performing | Residential real estate and consumer loans
Loan and Lease Financings
Recorded investment in loans and leases	651,785	648,481
Performing | Residential real estate and home equity
Loan and Lease Financings
Recorded investment in loans and leases	523,803	518,896
Performing | Consumer
Loan and Lease Financings
Recorded investment in loans and leases	$ 127,982	129,585
Nonperforming
Loan and Lease Financings
Classification of nonperforming loans, threshold period past due	90 days
Nonperforming | Residential real estate and consumer loans
Loan and Lease Financings
Recorded investment in loans and leases	$ 2,483	3,263
Nonperforming | Residential real estate and home equity
Loan and Lease Financings
Recorded investment in loans and leases	2,319	3,035
Nonperforming | Consumer
Loan and Lease Financings
Recorded investment in loans and leases	$ 164	$ 228