Allowance For Loan Losses And Credit Quality Of Financing Receivables - Allowances Of Loan Losses And Loans Receivable By Class Disaggregated (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance, Allowance for Loan Losses	$ 6,797	$ 6,696	$ 5,812	$ 5,590
Allowance for Loan Losses, Balance Related to Loans Individually Evaluated for Impairment	38	155
Allowance for Loan Losses, Balance Related to Loans Collectively Evaluated for Impairment	5,446	5,164
Total Financing Receivables	719,690	696,142
Loans Receivable, Individually Evaluated for Impairment	6,035	6,597
Loans Receivable, Collectively Evaluated for Impairment	713,655	689,545
Commercial And Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance, Allowance for Loan Losses	92	110	98	85
Allowance for Loan Losses, Balance Related to Loans Individually Evaluated for Impairment	0	14
Allowance for Loan Losses, Balance Related to Loans Collectively Evaluated for Impairment	92	96
Total Financing Receivables	35,906	40,280
Loans Receivable, Individually Evaluated for Impairment	19	33
Loans Receivable, Collectively Evaluated for Impairment	35,887	40,247
Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance, Allowance for Loan Losses	425	359	267	220
Allowance for Loan Losses, Balance Related to Loans Individually Evaluated for Impairment	0	0
Allowance for Loan Losses, Balance Related to Loans Collectively Evaluated for Impairment	425	359
Total Financing Receivables	35,662	25,360
Loans Receivable, Individually Evaluated for Impairment	0	0
Loans Receivable, Collectively Evaluated for Impairment	35,662	25,360
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance, Allowance for Loan Losses	4,025	3,932	3,847	3,646
Allowance for Loan Losses, Balance Related to Loans Individually Evaluated for Impairment	31	135
Allowance for Loan Losses, Balance Related to Loans Collectively Evaluated for Impairment	3,994	3,797
Total Financing Receivables	485,617	479,227
Loans Receivable, Individually Evaluated for Impairment	4,302	4,597
Loans Receivable, Collectively Evaluated for Impairment	481,315	474,630
Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance, Allowance for Loan Losses	925	899	908	784
Allowance for Loan Losses, Balance Related to Loans Individually Evaluated for Impairment	7	6
Allowance for Loan Losses, Balance Related to Loans Collectively Evaluated for Impairment	918	893
Total Financing Receivables	161,543	150,237
Loans Receivable, Individually Evaluated for Impairment	1,714	1,967
Loans Receivable, Collectively Evaluated for Impairment	159,829	148,270
Consumer And Other [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance, Allowance for Loan Losses	17	19	121	87
Allowance for Loan Losses, Balance Related to Loans Individually Evaluated for Impairment	0	0
Allowance for Loan Losses, Balance Related to Loans Collectively Evaluated for Impairment	17	19
Total Financing Receivables	962	1,038
Loans Receivable, Individually Evaluated for Impairment	0	0
Loans Receivable, Collectively Evaluated for Impairment	962	1,038
Unallocated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance, Allowance for Loan Losses	1,313	1,377	$ 571	$ 768
Total Financing Receivables	$ 0	$ 0

A valuation allowance for financing receivables that are expected to be uncollectible.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953423-111524

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- Definition

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

+ 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)
-URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953423-111524

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- Definition

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

+ 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)
-URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953423-111524

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

The balance of financing receivables that were collectively evaluated for impairment.

+ 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 (h)
-URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953423-111524

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- Definition

The balance of financing receivables that were individually evaluated for impairment.

+ 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 (h)
-URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953423-111524

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- Definition

Net amount of the investment in a contractual right to receive money on demand or on fixed or determinable dates that is recognized as an asset in the creditor's statement of financial position. Examples include, but are not limited to, credit card receivables, notes receivable and receivables relating to lessor's rights to payments from leases other than operating leases that have been recorded as assets. Excludes trade accounts receivable with contractual maturity of one year or less and arose from the sale of goods or services.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.3)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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