PARENT COMPANY ONLY CONDENSED FINANCIAL INFORMATION - Condensed Statements of Income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Condensed financial information
Interest expense	$ 8,672	$ 9,639	$ 10,835	$ 10,192	$ 9,382	$ 8,375	$ 7,622	$ 6,825	$ 39,338	$ 32,204	$ 22,689
Non-interest expense	25,332	24,204	24,004	22,599	22,071	31,004	22,507	22,598	96,139	98,180	91,727
Income tax benefit	3,934	3,852	2,859	3,415	2,878	1,381	1,701	3,181	14,060	9,141	18,946
Net income	$ 14,208	$ 13,903	$ 10,653	$ 12,927	$ 13,864	$ 6,547	$ 6,743	$ 12,073	51,691	39,227	20,539
Parent Company
Condensed financial information
Dividends from the Bank									24,500	15,000	0
Interest expense									4,539	4,539	4,588
Non-interest expense									104	135	147
Income (loss) before income taxes and equity in undistributed earnings of the Bank									19,857	10,326	(4,735)
Income tax benefit									(994)	(1,005)	(1,774)
Income (loss) before equity in undistributed earnings of the Bank									20,851	11,331	(2,961)
Equity in undistributed earnings of the Bank									30,840	27,896	23,500
Net income									$ 51,691	$ 39,227	$ 20,539