Allowance for Loan Losses and Reserve for Unfunded Lending Commitments (Details) - USD ($) $ in Thousands	3 Months Ended			12 Months Ended
	Mar. 31, 2017		Mar. 31, 2016	Dec. 31, 2016		Mar. 31, 2017	Dec. 31, 2016
Allowance for Loan Losses
Balance, beginning of period	$ 12,801	[1]	$ 12,601	$ 12,601
Provision for loan losses	300		50	250
Charge-offs	(49)		(40)	(326)
Recoveries	56		64	276
Balance, end of period	13,108		12,675	12,801	[1]
Reserve for Unfunded Lending Commitments
Balance, beginning of period	203		184	184
Provision for unfunded commitments	3		4	19
Charge-offs	0		0	0
Balance, end of period	206		188	203
Allowance for Loan Losses
Individually evaluated for impairment						$ 22	$ 23
Collectively evaluated for impairment						12,691	12,429
Total	12,801	[1]	12,601	12,601		13,108	12,801	[1]
Loans
Individually evaluated for impairment						3,652	4,844
Collectively evaluated for impairment						1,188,345	1,131,308
Total Loans						1,219,958	1,164,821	[1]
Purchased impaired loans
Allowance for Loan Losses
Balance, beginning of period	349
Balance, end of period	395			349
Allowance for Loan Losses
Total	349			349		395	349
Loans
Total Loans						27,961	28,669
Commercial
Allowance for Loan Losses
Balance, beginning of period	2,095		2,065	2,065
Provision for loan losses	140			30
Charge-offs	(2)			(40)
Recoveries	2			40
Balance, end of period	2,235			2,095
Allowance for Loan Losses
Individually evaluated for impairment						0	0
Collectively evaluated for impairment						2,174	2,087
Total	2,095		2,065	2,065		2,235	2,095
Loans
Individually evaluated for impairment						118	43
Collectively evaluated for impairment						218,991	208,258
Total Loans						219,455	208,717
Commercial | Purchased impaired loans
Allowance for Loan Losses
Balance, beginning of period	8
Balance, end of period	61			8
Allowance for Loan Losses
Total	8			8		61	8
Loans
Total Loans						346	416
Commercial Real Estate
Allowance for Loan Losses
Balance, beginning of period	7,355		6,930	6,930
Provision for loan losses	341			403
Charge-offs	(1)			(10)
Recoveries	6			32
Balance, end of period	7,701			7,355
Allowance for Loan Losses
Individually evaluated for impairment						0	0
Collectively evaluated for impairment						7,596	7,248
Total	7,355		6,930	6,930		7,701	7,355
Loans
Individually evaluated for impairment						1,290	2,186
Collectively evaluated for impairment						655,244	610,462
Total Loans						668,760	625,218
Commercial Real Estate | Purchased impaired loans
Allowance for Loan Losses
Balance, beginning of period	107
Balance, end of period	105			107
Allowance for Loan Losses
Total	107			107		105	107
Loans
Total Loans						12,226	12,570
Residential Real Estate
Allowance for Loan Losses
Balance, beginning of period	3,303		3,546	3,546
Provision for loan losses	(184)			(224)
Charge-offs	(4)			(87)
Recoveries	12			68
Balance, end of period	3,127			3,303
Allowance for Loan Losses
Individually evaluated for impairment						22	23
Collectively evaluated for impairment						2,876	3,046
Total	3,303		3,546	3,546		3,127	3,303
Loans
Individually evaluated for impairment						2,226	2,588
Collectively evaluated for impairment						309,279	307,600
Total Loans						326,879	325,855
Residential Real Estate | Purchased impaired loans
Allowance for Loan Losses
Balance, beginning of period	234
Balance, end of period	229			234
Allowance for Loan Losses
Total	234			234		229	234
Loans
Total Loans						15,374	15,667
Consumer
Allowance for Loan Losses
Balance, beginning of period	48		60	60
Provision for loan losses	3			41
Charge-offs	(42)			(189)
Recoveries	36			136
Balance, end of period	45			48
Allowance for Loan Losses
Individually evaluated for impairment						0	0
Collectively evaluated for impairment						45	48
Total	48		$ 60	60		45	48
Loans
Individually evaluated for impairment						18	27
Collectively evaluated for impairment						4,831	4,988
Total Loans						4,864	5,031
Consumer | Purchased impaired loans
Allowance for Loan Losses
Balance, beginning of period	0
Balance, end of period	0			0
Allowance for Loan Losses
Total	$ 0			$ 0		0	0
Loans
Total Loans						$ 15	$ 16

[1] Derived from audited consolidated financial statements.