Selected Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Selected Quarterly Financial Data [Abstract]
Interest income	$ 12,338	$ 11,635	$ 11,289	$ 10,913	$ 11,241	$ 10,989	$ 10,661	$ 10,494
Interest expense	2,780	2,484	2,221	1,886	1,593	1,483	1,382	1,262	$ 9,371	$ 5,720
Net interest income	9,558	9,151	9,068	9,027	9,648	9,506	9,279	9,232	36,804	37,665
Provision for credit losses	350	100	375	375	375	375	585	325	1,200	1,660
Non-interest income	1,269	1,371	1,332	1,273	1,419	1,271	1,422	1,306	5,245	5,418
Non-interest expense	6,832	6,773	7,540	6,730	7,202	6,990	7,084	6,745	27,875	28,021
Income before income tax expense	3,645	3,649	2,485	3,195	3,490	3,412	3,032	3,468	12,974	13,402
Income tax expense	643	629	436	582	2,682	1,001	746	1,027	2,290	5,456
Net income	$ 3,002	$ 3,020	$ 2,049	$ 2,613	$ 808	$ 2,411	$ 2,286	$ 2,441	$ 10,684	$ 7,946
Per Share Data
Basic	$ 0.70	$ 0.70	$ 0.48	$ 0.61	$ 0.19	$ 0.57	$ 0.54	$ 0.57	$ 2.48	$ 1.87
Diluted	0.69	0.70	0.47	0.61	0.19	0.56	0.53	0.57	2.48	1.85
Cash dividends	$ 0.07	$ 0.07	$ 0.07	$ 0.07	$ 0.07	$ 0.07	$ 0.07	$ 0.07	$ 0.28	$ 0.28