Loans and Allowance for Loan Losses - Allowance (Details) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended		33 Months Ended
	Dec. 31, 2013 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($) quarters	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($)	Dec. 31, 2015 USD ($)
Activity in the allowance for loan losses:
Net deferred fees and costs		$ 796	$ 1,200	$ 796	$ 1,200	$ 796
Number of consecutive historical quarters utilized in charge-off factor calculation | quarters				12
Unfunded commitment liability		224	194	$ 224	194	224
Changes in the allowance for loan losses
Balance at beginning of period		9,091	7,047	8,006	6,223
Charge-offs		(1,018)	(304)	(1,844)	(727)
Recoveries		2	9	13	36
Provision		1,075	636	2,975	1,856
Balance at end of period		9,150	7,388	9,150	7,388	9,150
Individually evaluated for impairment		1,346	930	1,346	930	1,346
Collectively evaluated for impairment		7,804	6,458	7,804	6,458	7,804
Commercial
Changes in the allowance for loan losses
Balance at beginning of period		6,956	5,201	6,066	4,363
Charge-offs		(768)	(299)	(1,448)	(708)
Recoveries		1	0	3	21
Provision		967	515	2,535	1,741
Balance at end of period		7,156	5,417	7,156	5,417	7,156
Individually evaluated for impairment		1,288	595	1,288	595	1,288
Collectively evaluated for impairment		5,868	4,822	5,868	4,822	5,868
Loans acquired, purchase price	$ 74,300
Premium on loans acquired, ratio	1.024
Loans acquired, premium paid	$ 1,800
Loans acquired, outstanding balance		$ 25,800		$ 25,800		25,800	$ 46,800
Loans acquired, balance decrease						48,500
Loans acquired, refinanced						19,600
Loans acquired, sold in participation						7,500
Loans acquired, sold back to institution						$ 9,700
Loans acquired, remaining portfolio, weighted average yield		5.91%		5.91%		5.91%
Residential
Changes in the allowance for loan losses
Balance at beginning of period		$ 1,011	1,018	$ 1,095	962
Charge-offs		0	0	(124)	(14)
Recoveries		1	0	2	1
Provision		11	101	50	170
Balance at end of period		1,023	1,119	1,023	1,119	$ 1,023
Individually evaluated for impairment		38	301	38	301	38
Collectively evaluated for impairment		985	818	985	818	985
Home Equity
Changes in the allowance for loan losses
Balance at beginning of period		758	632	715	691
Charge-offs		0	0	0	0
Recoveries		0	0	7	1
Provision		2	78	38	18
Balance at end of period		760	710	760	710	760
Individually evaluated for impairment		0	28	0	28	0
Collectively evaluated for impairment		760	682	760	682	760
Consumer
Changes in the allowance for loan losses
Balance at beginning of period		366	196	130	207
Charge-offs		(250)	(5)	(272)	(5)
Recoveries		0	9	1	13
Provision		95	(58)	352	(73)
Balance at end of period		211	142	211	142	211
Individually evaluated for impairment		20	6	20	6	20
Collectively evaluated for impairment		$ 191	$ 136	$ 191	$ 136	$ 191