LOANS HELD FOR INVESTMENT, Activity in Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
LOANS HELD FOR INVESTMENT [Abstract]
Ratio of allowance for loan losses to loans held for investment	1.76%			1.76%		2.05%
Allowance for Loan Losses [Roll Forward]
Beginning Balance	$ 42,963		$ 40,635	$ 45,553	$ 24,197
Provision for loan losses	0	$ 2,000	6,062	(1,918)	25,429
Charge-offs	(342)		(1,011)	(1,480)	(4,694)
Recoveries	147		390	613	1,144
Ending Balance	42,768	42,963	46,076	42,768	46,076
Commercial Real Estate [Member]
Allowance for Loan Losses [Roll Forward]
Beginning Balance	17,288		15,156	18,962	5,049
Provision for loan losses	960		3,085	(714)	12,977
Charge-offs	0		0	0	0
Recoveries	0		23	0	238
Ending Balance	18,248	17,288	18,264	18,248	18,264
Commercial [Member] | Specialized [Member]
Allowance for Loan Losses [Roll Forward]
Beginning Balance	4,823		6,614	5,760	2,287
Provision for loan losses	(596)		(220)	(1,627)	4,870
Charge-offs	(16)		(109)	(21)	(959)
Recoveries	20		19	119	106
Ending Balance	4,231	4,823	6,304	4,231	6,304
Commercial [Member] | General [Member]
Allowance for Loan Losses [Roll Forward]
Beginning Balance	8,948		9,293	9,227	9,609
Provision for loan losses	(838)		977	(870)	1,952
Charge-offs	(2)		(372)	(379)	(1,752)
Recoveries	63		91	193	180
Ending Balance	8,171	8,948	9,989	8,171	9,989
Consumer [Member] | 1-4 Family Residential [Member]
Allowance for Loan Losses [Roll Forward]
Beginning Balance	5,064		2,926	4,646	2,093
Provision for loan losses	135		1,688	602	2,520
Charge-offs	0		(56)	(52)	(56)
Recoveries	2		126	5	127
Ending Balance	5,201	5,064	4,684	5,201	4,684
Consumer [Member] | Auto Loans [Member]
Allowance for Loan Losses [Roll Forward]
Beginning Balance	3,815		3,939	4,226	3,385
Provision for loan losses	79		474	(88)	1,624
Charge-offs	(111)		(212)	(438)	(916)
Recoveries	20		32	103	140
Ending Balance	3,803	3,815	4,233	3,803	4,233
Consumer [Member] | Other Consumer [Member]
Allowance for Loan Losses [Roll Forward]
Beginning Balance	1,434		1,640	1,671	1,341
Provision for loan losses	139		250	132	1,045
Charge-offs	(213)		(262)	(590)	(1,011)
Recoveries	42		99	189	352
Ending Balance	1,402	1,434	1,727	1,402	1,727
Construction [Member]
Allowance for Loan Losses [Roll Forward]
Beginning Balance	1,591		1,067	1,061	433
Provision for loan losses	121		(192)	647	441
Charge-offs	0		0	0	0
Recoveries	0		0	4	1
Ending Balance	$ 1,712	$ 1,591	$ 875	$ 1,712	$ 875