Allowance for Loan Losses - Composition of Allowance for Loans Losses, by Class (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for Loans Evaluated Individually for Impairment	$ 1,812	$ 974	$ 754
Allowance for Loans Evaluated Collectively for Impairment	8,917	9,164	9,162
Total Allowance for Loan Losses	10,729	10,138	9,916	$ 10,344
Commercial \| Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for Loans Evaluated Individually for Impairment	224	505	89
Allowance for Loans Evaluated Collectively for Impairment	3,648	3,483	3,031
Total Allowance for Loan Losses	3,872	3,988	3,120	3,532
Commercial \| Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for Loans Evaluated Individually for Impairment	0	100	302
Allowance for Loans Evaluated Collectively for Impairment	434	296	278
Total Allowance for Loan Losses	434	396	580	823
Commercial \| Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for Loans Evaluated Individually for Impairment	1,309	39	8
Allowance for Loans Evaluated Collectively for Impairment	2,049	1,741	1,444
Total Allowance for Loan Losses	3,358	1,780	1,452	1,505
Municipal
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for Loans Evaluated Individually for Impairment	0	0	0
Allowance for Loans Evaluated Collectively for Impairment	20	18	17
Total Allowance for Loan Losses	20	18	17	15
Residential \| Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for Loans Evaluated Individually for Impairment	0	0	0
Allowance for Loans Evaluated Collectively for Impairment	36	44	24
Total Allowance for Loan Losses	36	44	24	20
Residential \| Term
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for Loans Evaluated Individually for Impairment	255	304	326
Allowance for Loans Evaluated Collectively for Impairment	875	984	1,065
Total Allowance for Loan Losses	1,130	1,288	1,391	1,185
Home Equity LIne of Credit
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for Loans Evaluated Individually for Impairment	24	26	29
Allowance for Loans Evaluated Collectively for Impairment	668	781	864
Total Allowance for Loan Losses	692	807	893	1,060
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for Loans Evaluated Individually for Impairment	0	0	0
Allowance for Loans Evaluated Collectively for Impairment	545	559	566
Total Allowance for Loan Losses	545	559	566	542
Unallocated
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for Loans Evaluated Individually for Impairment	0	0	0
Allowance for Loans Evaluated Collectively for Impairment	642	1,258	1,873
Total Allowance for Loan Losses	$ 642	$ 1,258	$ 1,873	$ 1,662

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The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

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Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (g)
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-Publisher FASB
-Name Accounting Standards Codification
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-Section S99
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-Publisher FASB
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