Allowance for Loan and Lease Losses - Credit Quality Indicators by Class of Residential Real Estate (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Originated Loans and Leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases, gross	$ 1,362,489	$ 1,314,210
Originated Loans and Leases | Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases, gross	1,352,701	1,306,211
Originated Loans and Leases | Nonperforming
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases, gross	9,788	7,999
Originated Loans and Leases | Residential real estate | Residential Home Equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases, gross	208,459	212,812
Originated Loans and Leases | Residential real estate | Residential Mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases, gross	1,083,802	1,039,040
Originated Loans and Leases | Residential real estate | Performing | Residential Home Equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases, gross	206,675	211,275
Originated Loans and Leases | Residential real estate | Performing | Residential Mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases, gross	1,076,032	1,032,932
Originated Loans and Leases | Residential real estate | Nonperforming | Residential Home Equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases, gross	1,784	1,537
Originated Loans and Leases | Residential real estate | Nonperforming | Residential Mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases, gross	7,770	6,108
Originated Loans and Leases | Consumer and other | Consumer Indirect
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases, gross	12,663	12,144
Originated Loans and Leases | Consumer and other | Consumer Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases, gross	57,565	50,214
Originated Loans and Leases | Consumer and other | Performing | Consumer Indirect
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases, gross	12,508	11,866
Originated Loans and Leases | Consumer and other | Performing | Consumer Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases, gross	57,486	50,138
Originated Loans and Leases | Consumer and other | Nonperforming | Consumer Indirect
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases, gross	155	278
Originated Loans and Leases | Consumer and other | Nonperforming | Consumer Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases, gross	79	76
Acquired Loans and Leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases, gross	42,394	51,854
Acquired Loans and Leases | Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases, gross	39,876	49,136
Acquired Loans and Leases | Nonperforming
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases, gross	2,518	2,718
Acquired Loans and Leases | Residential real estate | Residential Home Equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases, gross	21,149	28,444
Acquired Loans and Leases | Residential real estate | Residential Mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases, gross	20,484	22,645
Acquired Loans and Leases | Residential real estate | Performing | Residential Home Equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases, gross	19,735	26,840
Acquired Loans and Leases | Residential real estate | Performing | Residential Mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases, gross	19,380	21,531
Acquired Loans and Leases | Residential real estate | Nonperforming | Residential Home Equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases, gross	1,414	1,604
Acquired Loans and Leases | Residential real estate | Nonperforming | Residential Mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases, gross	1,104	1,114
Acquired Loans and Leases | Consumer and other | Consumer Indirect
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases, gross	0	0
Acquired Loans and Leases | Consumer and other | Consumer Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases, gross	761	765
Acquired Loans and Leases | Consumer and other | Performing | Consumer Indirect
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases, gross	0	0
Acquired Loans and Leases | Consumer and other | Performing | Consumer Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases, gross	761	765
Acquired Loans and Leases | Consumer and other | Nonperforming | Consumer Indirect
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases, gross	0	0
Acquired Loans and Leases | Consumer and other | Nonperforming | Consumer Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases, gross	$ 0	$ 0