Loans and Allowance for Loan Losses - Allowance (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Activity in the allowance for loan losses:
Individually evaluated for impairment	$ 421	$ 1,346	$ 421	$ 1,346
Collectively evaluated for impairment	8,975	7,804	8,975	7,804
Changes in the allowance for loan losses
Balance at beginning of period	9,748	9,091	9,101	8,006
Charge-offs	(472)	(1,018)	(925)	(1,844)
Recoveries	24	2	83	13
Provision	96	1,075	1,137	2,975
Balance at end of period	9,396	9,150	9,396	9,150
Commercial
Activity in the allowance for loan losses:
Individually evaluated for impairment	420	1,288	420	1,288
Collectively evaluated for impairment	6,884	5,868	6,884	5,868
Changes in the allowance for loan losses
Balance at beginning of period	7,723	6,956	7,181	6,066
Charge-offs	(382)	(768)	(645)	(1,448)
Recoveries	1	1	22	3
Provision	(38)	967	746	2,535
Balance at end of period	7,304	7,156	7,304	7,156
Residential
Activity in the allowance for loan losses:
Individually evaluated for impairment	0	38	0	38
Collectively evaluated for impairment	1,044	985	1,044	985
Changes in the allowance for loan losses
Balance at beginning of period	992	1,011	990	1,095
Charge-offs	0	0	(141)	(124)
Recoveries	6	1	40	2
Provision	46	11	155	50
Balance at end of period	1,044	1,023	1,044	1,023
Home Equity
Activity in the allowance for loan losses:
Individually evaluated for impairment	1	0	1	0
Collectively evaluated for impairment	788	760	788	760
Changes in the allowance for loan losses
Balance at beginning of period	777	758	728	715
Charge-offs	0	0	(33)	0
Recoveries	1	0	3	7
Provision	11	2	91	38
Balance at end of period	789	760	789	760
Consumer
Activity in the allowance for loan losses:
Individually evaluated for impairment	0	20	0	20
Collectively evaluated for impairment	259	191	259	191
Changes in the allowance for loan losses
Balance at beginning of period	256	366	202	130
Charge-offs	(90)	(250)	(106)	(272)
Recoveries	16	0	18	1
Provision	77	95	145	352
Balance at end of period	$ 259	$ 211	$ 259	$ 211

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

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- Definition

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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- 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.

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No definition available.

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

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- Definition

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

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No definition available.

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

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- 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

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