PARENT COMPANY ONLY CONDENSED FINANCIAL INFORMATION - Condensed Statements of Income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Condensed financial information
Interest expense	$ 4,492	$ 5,589	$ 5,418	$ 7,952	$ 8,672	$ 9,639	$ 10,835	$ 10,192	$ 23,451	$ 39,338	$ 32,204
Non-interest expense	35,078	28,937	24,399	24,843	25,332	24,204	24,004	22,599	113,257	96,139	98,180
Income tax benefit	3,881	3,999	3,129	2,676	3,934	3,852	2,859	3,415	13,685	14,060	9,141
Net income	$ 8,977	$ 13,061	$ 10,656	$ 9,348	$ 14,208	$ 13,903	$ 10,653	$ 12,927	42,042	51,691	39,227
Parent Company
Condensed financial information
Dividends from the Bank									26,500	24,500	15,000
Interest expense									4,401	4,539	4,539
Non-interest expense									252	104	135
Income before income taxes and equity in undistributed earnings of the Bank									21,847	19,857	10,326
Income tax benefit									(1,280)	(994)	(1,005)
Income before equity in undistributed earnings of the Bank									23,127	20,851	11,331
Equity in undistributed earnings of the Bank									18,915	30,840	27,896
Net income									$ 42,042	$ 51,691	$ 39,227