Allowance for Loan and Lease Losses - Changes in Allowance for Loan and Lease Losses (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	$ 10,262	$ 10,008	$ 10,420	$ 9,689	$ 9,689
Charge-offs	(337)	(425)	(1,229)	(1,128)	(1,300)
Recoveries	39	93	419	706	789
(Credit) provision	159	578	513	987	1,242
Ending balance	10,123	10,254	10,123	10,254	10,420
Ending balance: related to loans individually evaluated for impairment	240	186	240	186	368
Ending balance: related to loans collectively evaluated for impairment	9,883	10,068	9,883	10,068	10,052
LHFI [Abstract]
Ending balance	594,565	575,818	594,565	575,818	602,009
Ending balance: individually evaluated for impairment	5,263	5,335	5,263	5,335	6,955
Ending balance: collectively evaluated for impairment	589,302	570,483	589,302	570,483	595,054
Commercial real estate
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	3,161	3,342	3,295	3,622	3,622
Charge-offs	0	(7)	(79)	(84)	(84)
Recoveries	0	17	0	201	201
(Credit) provision	(7)	(12)	(62)	(399)	(444)
Ending balance	3,154	3,340	3,154	3,340	3,295
Ending balance: related to loans individually evaluated for impairment	0	0	0	0	3
Ending balance: related to loans collectively evaluated for impairment	3,154	3,340	3,154	3,340	3,292
LHFI [Abstract]
Ending balance	256,452	253,074	256,452	253,074	261,561
Ending balance: individually evaluated for impairment	1,496	852	1,496	852	904
Ending balance: collectively evaluated for impairment	254,956	252,222	254,956	252,222	260,657
Construction and land development
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	2,273	1,991	2,294	1,674	1,674
Charge-offs	0	0	0	0	0
Recoveries	0	15	351	273	306
(Credit) provision	(264)	160	(636)	219	314
Ending balance	2,009	2,166	2,009	2,166	2,294
Ending balance: related to loans individually evaluated for impairment	0	0	0	0	0
Ending balance: related to loans collectively evaluated for impairment	2,009	2,166	2,009	2,166	2,294
LHFI [Abstract]
Ending balance	78,389	74,885	78,389	74,885	83,369
Ending balance: individually evaluated for impairment	128	144	128	144	144
Ending balance: collectively evaluated for impairment	78,261	74,741	78,261	74,741	83,225
Commercial and industrial
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	1,371	1,365	1,346	1,513	1,513
Charge-offs	0	0	0	(108)	(107)
Recoveries	0	32	0	159	174
(Credit) provision	(45)	17	(20)	(150)	(234)
Ending balance	1,326	1,414	1,326	1,414	1,346
Ending balance: related to loans individually evaluated for impairment	0	0	0	0	0
Ending balance: related to loans collectively evaluated for impairment	1,326	1,414	1,326	1,414	1,346
LHFI [Abstract]
Ending balance	110,861	106,254	110,861	106,254	108,146
Ending balance: individually evaluated for impairment	1,562	2,120	1,562	2,120	2,105
Ending balance: collectively evaluated for impairment	109,299	104,134	109,299	104,134	106,041
Multi-family
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	344	231	263	171	171
Charge-offs	0	0	0	0	0
Recoveries	0	0	0	0	0
(Credit) provision	43	36	124	96	92
Ending balance	387	267	387	267	263
Ending balance: related to loans individually evaluated for impairment	0	0	0	0	0
Ending balance: related to loans collectively evaluated for impairment	387	267	387	267	263
LHFI [Abstract]
Ending balance	33,751	23,831	33,751	23,831	23,389
Ending balance: individually evaluated for impairment	0	0	0	0	0
Ending balance: collectively evaluated for impairment	33,751	23,831	33,751	23,831	23,389
Residential real estate
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	623	647	656	586	586
Charge-offs	0	0	(8)	(40)	(40)
Recoveries	6	4	21	23	35
(Credit) provision	(5)	(76)	(45)	6	75
Ending balance	624	575	624	575	656
Ending balance: related to loans individually evaluated for impairment	15	18	15	18	17
Ending balance: related to loans collectively evaluated for impairment	609	557	609	557	639
LHFI [Abstract]
Ending balance	55,643	49,061	55,643	49,061	56,899
Ending balance: individually evaluated for impairment	591	668	591	668	653
Ending balance: collectively evaluated for impairment	55,052	48,393	55,052	48,393	56,246
Leases
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	2,292	2,052	2,295	1,749	1,749
Charge-offs	(322)	(310)	(1,119)	(757)	(930)
Recoveries	33	18	47	35	57
(Credit) provision	442	426	1,222	1,159	1,419
Ending balance	2,445	2,186	2,445	2,186	2,295
Ending balance: related to loans individually evaluated for impairment	225	168	225	168	340
Ending balance: related to loans collectively evaluated for impairment	2,220	2,018	2,220	2,018	1,955
LHFI [Abstract]
Ending balance	55,270	62,671	55,270	62,671	61,838
Ending balance: individually evaluated for impairment	1,017	806	1,017	806	1,242
Ending balance: collectively evaluated for impairment	54,253	61,865	54,253	61,865	60,596
Tax certificates
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	170	358	242	347	347
Charge-offs	(15)	(108)	(23)	(139)	(139)
Recoveries	0	6	0	14	14
(Credit) provision	(19)	29	(83)	63	20
Ending balance	136	285	136	285	242
Ending balance: related to loans individually evaluated for impairment	0	0	0	0	8
Ending balance: related to loans collectively evaluated for impairment	136	285	136	285	234
LHFI [Abstract]
Ending balance	1,290	3,803	1,290	3,803	3,705
Ending balance: individually evaluated for impairment	469	745	469	745	1,907
Ending balance: collectively evaluated for impairment	821	3,058	821	3,058	1,798
Consumer
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	28	22	29	27	27
Charge-offs	0	0	0	0	0
Recoveries	0	1	0	1	2
(Credit) provision	14	(2)	13	(7)	0
Ending balance	42	21	42	21	29
Ending balance: related to loans individually evaluated for impairment	0	0	0	0	0
Ending balance: related to loans collectively evaluated for impairment	42	21	42	21	29
LHFI [Abstract]
Ending balance	2,909	2,239	2,909	2,239	3,102
Ending balance: individually evaluated for impairment	0	0	0	0	0
Ending balance: collectively evaluated for impairment	2,909	2,239	2,909	2,239	3,102
Unallocated
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	0	0	0	0	0
Charge-offs	0	0		0	0
Recoveries	0	0		0	0
(Credit) provision	0	0		0	0
Ending balance	0	0	0	0	0
Ending balance: related to loans individually evaluated for impairment	0	0	0	0	0
Ending balance: related to loans collectively evaluated for impairment	0	0	0	0	0
LHFI [Abstract]
Ending balance	0	0	0	0	0
Ending balance: individually evaluated for impairment	0	0	0	0	0
Ending balance: collectively evaluated for impairment	$ 0	$ 0	$ 0	$ 0	$ 0

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

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

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

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

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- Definition

Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes 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 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=65884687&loc=d3e4428-111522

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-Publisher FASB
-Name Accounting Standards Codification
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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.

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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)
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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

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-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3602-108585

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