Quarterly Financial Data (unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Total interest income	$ 16,764	$ 15,471	$ 13,971	$ 12,693	$ 11,594	$ 10,536	$ 10,130	$ 9,187	$ 58,899	$ 41,447	$ 31,215
Total interest expense	5,860	5,133	4,665	3,552	3,026	2,697	2,558	2,413	19,210	10,694	8,928
Net interest income	10,904	10,338	9,306	9,141	8,568	7,839	7,572	6,774	39,689	30,753	22,287
Provision for loan losses	256	2,204	924	946	746	454	304	442	4,330	1,946	349
Net interest income after provision for loan losses	10,648	8,134	8,382	8,195	7,822	7,385	7,268	6,332	35,359	28,807	21,938
Total noninterest income	2,891	4,898	3,748	2,540	2,143	2,374	2,476	3,148	14,077	10,141	7,174
Total noninterest expense	8,158	8,413	7,875	7,005	6,492	6,207	6,327	6,257	31,451	25,283	22,662
Income before income taxes	5,381	4,619	4,255	3,730	3,473	3,552	3,417	3,223	17,985	13,665	6,450
Income tax provision	1,671	1,521	1,421	1,298	1,195	1,229	1,152	1,160	5,911	4,736	2,126
Net income	$ 3,710	$ 3,098	$ 2,834	$ 2,432	$ 2,278	$ 2,323	$ 2,265	$ 2,063	$ 12,074	$ 8,929	$ 4,324
Basic (in dollars per share)	$ 0.65	$ 0.55	$ 0.57	$ 0.54	$ 0.50	$ 0.51	$ 0.50	$ 0.46	$ 2.32	$ 1.97	$ 0.96
Diluted (in dollars per share)	$ 0.64	$ 0.55	$ 0.57	$ 0.53	$ 0.50	$ 0.51	$ 0.50	$ 0.46	$ 2.30	$ 1.96	$ 0.96
Weighted-average common shares (in shares)	5,722,615	5,597,867	4,972,759	4,541,728	4,534,910	4,532,360	4,529,823	4,516,776	5,211,209	4,528,528	4,497,007
Diluted (shares)	5,761,931	5,622,181	4,992,025	4,575,555	4,580,353	4,574,455	4,550,034	4,523,246	5,239,082	4,554,219	4,507,995