LOANS HELD FOR INVESTMENT, Activity in Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
LOANS HELD FOR INVESTMENT [Abstract]
Percentage of allowance for loan losses to loans held for investment	2.01%		2.01%		1.13%
Allowance for Loan Losses [Roll Forward]
Beginning Balance	$ 40,635	$ 24,171	$ 24,197	$ 23,126
Provision for loan losses	6,062	420	25,429	1,903
Charge-offs	(1,011)	(725)	(4,694)	(1,940)
Recoveries	390	310	1,144	1,087
Ending Balance	46,076	24,176	46,076	24,176
Commercial Real Estate [Member]
Allowance for Loan Losses [Roll Forward]
Beginning Balance	15,156	5,415	5,049	5,579
Provision for loan losses	3,085	(379)	12,977	(758)
Charge-offs	0	0	0	0
Recoveries	23	108	238	323
Ending Balance	18,264	5,144	18,264	5,144
Commercial [Member] | Specialized [Member]
Allowance for Loan Losses [Roll Forward]
Beginning Balance	6,614	3,346	2,287	2,516
Provision for loan losses	(220)	(575)	4,870	230
Charge-offs	(109)	0	(959)	(37)
Recoveries	19	28	106	90
Ending Balance	6,304	2,799	6,304	2,799
Commercial [Member] | General [Member]
Allowance for Loan Losses [Roll Forward]
Beginning Balance	9,293	8,325	9,609	8,173
Provision for loan losses	977	734	1,952	674
Charge-offs	(372)	(170)	(1,752)	(235)
Recoveries	91	19	180	296
Ending Balance	9,989	8,908	9,989	8,908
Consumer [Member] | 1-4 Family Residential [Member]
Allowance for Loan Losses [Roll Forward]
Beginning Balance	2,926	2,310	2,093	2,249
Provision for loan losses	1,688	384	2,520	412
Charge-offs	(56)	(65)	(56)	(84)
Recoveries	126	9	127	61
Ending Balance	4,684	2,638	4,684	2,638
Consumer [Member] | Auto Loans [Member]
Allowance for Loan Losses [Roll Forward]
Beginning Balance	3,939	3,067	3,385	2,994
Provision for loan losses	474	127	1,624	626
Charge-offs	(212)	(260)	(916)	(765)
Recoveries	32	83	140	162
Ending Balance	4,233	3,017	4,233	3,017
Consumer [Member] | Other Consumer [Member]
Allowance for Loan Losses [Roll Forward]
Beginning Balance	1,640	1,199	1,341	1,192
Provision for loan losses	250	121	1,045	550
Charge-offs	(262)	(230)	(1,011)	(744)
Recoveries	99	63	352	155
Ending Balance	1,727	1,153	1,727	1,153
Construction [Member]
Allowance for Loan Losses [Roll Forward]
Beginning Balance	1,067	509	433	423
Provision for loan losses	(192)	8	441	169
Charge-offs	0	0	0	(75)
Recoveries	0	0	1	0
Ending Balance	$ 875	$ 517	$ 875	$ 517