Allowance for Credit Losses (Credit Quality Indicators) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	$ 864,345	$ 845,897
Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	846,693	832,646
Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	3,460	240
Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	14,192	13,011
Residential Mortgage [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	95,404	93,959
Residential Mortgage [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	93,075	91,993
Residential Mortgage [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	2,329	1,966
Commercial Mortgage [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	498,506	484,868
Commercial Mortgage [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	492,144	479,308
Commercial Mortgage [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	1,114	125
Commercial Mortgage [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	5,248	5,435
Commercial Term [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	131,144	129,535
Commercial Term [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	126,492	125,926
Commercial Term [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	577	115
Commercial Term [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	4,075	3,494
Commercial Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	78,863	75,014
Commercial Construction [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	75,620	73,902
Commercial Construction [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	1,769
Commercial Construction [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	1,474	1,112
Consumer: Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	55,002	56,844
Consumer: Home Equity [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	54,247	56,085
Consumer: Home Equity [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	755	759
Consumer: Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	5,426	5,677
Consumer: Other [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	5,115	5,432
Consumer: Other [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	$ 311	$ 245