Loans and Leases - Troubled Debt Restructurings (Details) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2018 USD ($) contract	Sep. 30, 2018 USD ($) contract	Dec. 31, 2017 USD ($)
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings | $	$ 5,524	$ 5,524	$ 9,089
Number of contracts	4	10
Pre-Modification Outstanding Recorded Investment | $	$ 406	$ 684
Post-Modification Outstanding Recorded Investment | $	$ 430	$ 708
Loan Term Extension
Financing Receivable, Modifications [Line Items]
Number of contracts	1	2
Interest Rate Change and Term Extension
Financing Receivable, Modifications [Line Items]
Number of contracts	0	3
Interest Rate Change and/or Interest-Only Period
Financing Receivable, Modifications [Line Items]
Number of contracts	0	0
Contractual Payment Reduction (Leases only)
Financing Receivable, Modifications [Line Items]
Number of contracts	0	2
Temporary Payment Deferral
Financing Receivable, Modifications [Line Items]
Number of contracts	3	3
Home equity loans and lines
Financing Receivable, Modifications [Line Items]
Number of contracts	0	1
Pre-Modification Outstanding Recorded Investment | $	$ 0	$ 8
Post-Modification Outstanding Recorded Investment | $	$ 0	$ 8
Home equity loans and lines | Loan Term Extension
Financing Receivable, Modifications [Line Items]
Number of contracts	0	0
Home equity loans and lines | Interest Rate Change and Term Extension
Financing Receivable, Modifications [Line Items]
Number of contracts	0	1
Home equity loans and lines | Interest Rate Change and/or Interest-Only Period
Financing Receivable, Modifications [Line Items]
Number of contracts	0	0
Home equity loans and lines | Contractual Payment Reduction (Leases only)
Financing Receivable, Modifications [Line Items]
Number of contracts	0	0
Home equity loans and lines | Temporary Payment Deferral
Financing Receivable, Modifications [Line Items]
Number of contracts	0	0
Residential mortgage
Financing Receivable, Modifications [Line Items]
Number of contracts	4	6
Pre-Modification Outstanding Recorded Investment | $	$ 406	$ 625
Post-Modification Outstanding Recorded Investment | $	$ 430	$ 649
Residential mortgage | Loan Term Extension
Financing Receivable, Modifications [Line Items]
Number of contracts	1	2
Residential mortgage | Interest Rate Change and Term Extension
Financing Receivable, Modifications [Line Items]
Number of contracts	0	1
Residential mortgage | Interest Rate Change and/or Interest-Only Period
Financing Receivable, Modifications [Line Items]
Number of contracts	0	0
Residential mortgage | Contractual Payment Reduction (Leases only)
Financing Receivable, Modifications [Line Items]
Number of contracts	0	0
Residential mortgage | Temporary Payment Deferral
Financing Receivable, Modifications [Line Items]
Number of contracts	3	3
Leases
Financing Receivable, Modifications [Line Items]
Number of contracts	0	2
Pre-Modification Outstanding Recorded Investment | $	$ 0	$ 33
Post-Modification Outstanding Recorded Investment | $	$ 0	$ 33
Leases | Loan Term Extension
Financing Receivable, Modifications [Line Items]
Number of contracts	0	0
Leases | Interest Rate Change and Term Extension
Financing Receivable, Modifications [Line Items]
Number of contracts	0	0
Leases | Interest Rate Change and/or Interest-Only Period
Financing Receivable, Modifications [Line Items]
Number of contracts	0	0
Leases | Contractual Payment Reduction (Leases only)
Financing Receivable, Modifications [Line Items]
Number of contracts	0	2
Leases | Temporary Payment Deferral
Financing Receivable, Modifications [Line Items]
Number of contracts	0	0
Commercial and industrial
Financing Receivable, Modifications [Line Items]
Number of contracts		1
Pre-Modification Outstanding Recorded Investment | $		$ 18
Post-Modification Outstanding Recorded Investment | $		$ 18
Commercial and industrial | Loan Term Extension
Financing Receivable, Modifications [Line Items]
Number of contracts		0
Commercial and industrial | Interest Rate Change and Term Extension
Financing Receivable, Modifications [Line Items]
Number of contracts		1
Commercial and industrial | Interest Rate Change and/or Interest-Only Period
Financing Receivable, Modifications [Line Items]
Number of contracts		0
Commercial and industrial | Contractual Payment Reduction (Leases only)
Financing Receivable, Modifications [Line Items]
Number of contracts		0
Commercial and industrial | Temporary Payment Deferral
Financing Receivable, Modifications [Line Items]
Number of contracts		0
Nonperforming Financial Instruments
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings | $	$ 1,208	$ 1,208	3,289
Performing Financial Instruments
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings | $	$ 4,316	$ 4,316	$ 5,800