Allowance for Loan Losses and Reserve for Unfunded Lending Commitments (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		Sep. 30, 2017	Dec. 31, 2016
Allowance for Loan Losses
Balance, beginning of period			$ 12,801	[1]	$ 12,601	$ 12,601
Provision for loan losses	$ 440	$ 100	1,090		200	250
Charge-offs			(411)		(245)	(326)
Recoveries			378		201	276
Balance, end of period	13,858	12,757	13,858		12,757	12,801	[1]
Reserve for Unfunded Lending Commitments
Balance, beginning of period			203		184	184
Provision for unfunded commitments			11		11	19
Charge-offs			0		0	0
Balance, end of period	214	195	214		195	203
Allowance for Loan Losses
Individually evaluated for impairment								$ 165	$ 23
Collectively evaluated for impairment								13,319	12,429
Total	13,858	$ 12,757	12,801	[1]	12,601	12,601		13,858	12,801	[1]
Loans
Individually evaluated for impairment								3,641	4,844
Collectively evaluated for impairment								1,266,653	1,131,308
Total Loans								1,295,154	1,164,821	[1]
Acquired impaired loans
Allowance for Loan Losses
Balance, beginning of period			349
Balance, end of period	374		374			349
Allowance for Loan Losses
Total	374		349			349		374	349
Loans
Total Loans								24,860	28,669
Commercial
Allowance for Loan Losses
Balance, beginning of period			2,095		2,065	2,065
Provision for loan losses			249			30
Charge-offs			(166)			(40)
Recoveries			219			40
Balance, end of period	2,397		2,397			2,095
Allowance for Loan Losses
Individually evaluated for impairment								155	0
Collectively evaluated for impairment								2,224	2,087
Total	2,397		2,095		2,065	2,065		2,397	2,095
Loans
Individually evaluated for impairment								257	43
Collectively evaluated for impairment								230,022	208,258
Total Loans								230,484	208,717
Commercial | Acquired impaired loans
Allowance for Loan Losses
Balance, beginning of period			8
Balance, end of period	18		18			8
Allowance for Loan Losses
Total	18		8			8		18	8
Loans
Total Loans								205	416
Commercial Real Estate
Allowance for Loan Losses
Balance, beginning of period			7,355		6,930	6,930
Provision for loan losses			1,061			403
Charge-offs			(35)			(10)
Recoveries			24			32
Balance, end of period	8,405		8,405			7,355
Allowance for Loan Losses
Individually evaluated for impairment								0	0
Collectively evaluated for impairment								8,274	7,248
Total	8,405		7,355		6,930	6,930		8,405	7,355
Loans
Individually evaluated for impairment								1,207	2,186
Collectively evaluated for impairment								726,347	610,462
Total Loans								740,303	625,218
Commercial Real Estate | Acquired impaired loans
Allowance for Loan Losses
Balance, beginning of period			107
Balance, end of period	131		131			107
Allowance for Loan Losses
Total	131		107			107		131	107
Loans
Total Loans								12,749	12,570
Residential Real Estate
Allowance for Loan Losses
Balance, beginning of period			3,303		3,546	3,546
Provision for loan losses			(247)			(224)
Charge-offs			(93)			(87)
Recoveries			49			68
Balance, end of period	3,012		3,012			3,303
Allowance for Loan Losses
Individually evaluated for impairment								10	23
Collectively evaluated for impairment								2,777	3,046
Total	3,012		3,303		3,546	3,546		3,012	3,303
Loans
Individually evaluated for impairment								2,170	2,588
Collectively evaluated for impairment								306,066	307,600
Total Loans								320,127	325,855
Residential Real Estate | Acquired impaired loans
Allowance for Loan Losses
Balance, beginning of period			234
Balance, end of period	225		225			234
Allowance for Loan Losses
Total	225		234			234		225	234
Loans
Total Loans								11,891	15,667
Consumer
Allowance for Loan Losses
Balance, beginning of period			48		60	60
Provision for loan losses			27			41
Charge-offs			(117)			(189)
Recoveries			86			136
Balance, end of period	44		44			48
Allowance for Loan Losses
Individually evaluated for impairment								0	0
Collectively evaluated for impairment								44	48
Total	44		48		$ 60	60		44	48
Loans
Individually evaluated for impairment								7	27
Collectively evaluated for impairment								4,218	4,988
Total Loans								4,240	5,031
Consumer | Acquired impaired loans
Allowance for Loan Losses
Balance, beginning of period			0
Balance, end of period	0		0			0
Allowance for Loan Losses
Total	$ 0		$ 0			$ 0		0	0
Loans
Total Loans								$ 15	$ 16

[1] Derived from audited consolidated financial statements.