Allowance For Loan Losses And Credit Quality Of Financing Receivables - Changes In The Allowance For Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	$ 7,335	$ 6,696
Charge-offs	(34)	(318)
Recoveries	19	12
Provision	508	407
Ending balance	7,828	6,797
Commercial and Industrial
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	208	110
Charge-offs	(11)	(13)
Recoveries	1	0
Provision	191	(5)
Ending balance	389	92
Construction
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	336	359
Charge-offs	0	0
Recoveries	0	0
Provision	9	66
Ending balance	345	425
Commercial Real Estate
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	5,185	3,932
Charge-offs	0	(266)
Recoveries	1	2
Provision	615	357
Ending balance	5,801	4,025
Residential Real Estate
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	1,032	899
Charge-offs	(12)	(34)
Recoveries	10	8
Provision	(58)	52
Ending balance	972	925
Consumer and Other
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	26	19
Charge-offs	(11)	(5)
Recoveries	7	2
Provision	9	1
Ending balance	31	17
Unallocated
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	548	1,377
Charge-offs	0	0
Recoveries	0	0
Provision	(258)	(64)
Ending balance	$ 290	$ 1,313

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

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of recovery of financing receivables doubtful of collection that were previously charged off.

+ References

+ Details

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Period Type:	duration

- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Amount of direct write-downs of financing receivables charged against the allowance.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of expense related loan transactions, lease transactions, credit loss from transactions other than loan and lease transactions, and other loss based on assessment of uncollectability from the counterparty to reduce the account to their net realizable value.

+ 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 (c)(2)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.11)
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

+ Details

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Balance Type:	debit
Period Type:	duration

- Details

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