CONDENSED FINANCIAL STATEMENTS OF PARENT COMPANY - Statements of Income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Condensed Financial Statements, Captions [Line Items]
Total revenue	$ 30,014	$ 30,438	$ 30,367	$ 27,318	$ 13,692	$ 14,371	$ 14,996	$ 14,664
Interest expense	6,660	6,585	5,856	4,813	3,189	3,124	2,972	2,828	$ 23,914	$ 12,113	$ 10,390
Non-interest expense	14,263	17,586	20,046	20,831	10,457	8,750	8,731	7,997	72,726	35,935	30,908
Income before income taxes	15,154	12,192	9,585	5,692	3,010	5,482	6,115	6,202	42,623	20,809	21,120
Income tax benefit	8,545	3,575	3,029	1,481	426	1,850	1,804	1,796	16,630	5,876	5,967
Net income	$ 6,609	$ 8,617	$ 6,556	$ 4,211	$ 2,584	$ 3,632	$ 4,311	$ 4,406	25,993	14,933	15,153
Parent Company
Condensed Financial Statements, Captions [Line Items]
Dividends from subsidiaries									13,907	6,473	5,407
Other									25	0	0
Total revenue									13,932	6,473	5,407
Interest expense									1,857	0	0
Non-interest expense									2,979	2,949	2,183
Total expense									4,836	2,949	2,183
Income before income taxes									9,096	3,524	3,224
Income tax benefit									(1,210)	(1,029)	(657)
Income before equity in undistributed income of subsidiaries									10,306	4,553	3,881
Equity in undistributed income of subsidiaries									15,687	10,380	11,272
Net income									$ 25,993	$ 14,933	$ 15,153