LOANS HELD FOR INVESTMENT, Age Analysis on Accruing Past-due Loans and Nonaccrual Loans (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2021 USD ($) Point	Dec. 31, 2020 USD ($)
Age Analysis on Accruing Past-due Loans and Nonaccrual Loans [Abstract]
Loans	$ 2,429,041	$ 2,221,583
Nonaccrual	$ 10,149	13,718
Number of points on a grading scale for loans | Point	13
30-89 Days Past Due [Member]
Age Analysis on Accruing Past-due Loans and Nonaccrual Loans [Abstract]
Loans	$ 4,853	6,560
90 Days or More Past Due [Member]
Age Analysis on Accruing Past-due Loans and Nonaccrual Loans [Abstract]
Loans	747	1,246
Commercial Real Estate [Member]
Age Analysis on Accruing Past-due Loans and Nonaccrual Loans [Abstract]
Loans	746,775	663,344
Nonaccrual	1,767	6,311
Commercial Real Estate [Member] | 30-89 Days Past Due [Member]
Age Analysis on Accruing Past-due Loans and Nonaccrual Loans [Abstract]
Loans	598	914
Commercial Real Estate [Member] | 90 Days or More Past Due [Member]
Age Analysis on Accruing Past-due Loans and Nonaccrual Loans [Abstract]
Loans	34	34
Commercial [Member] | Specialized [Member]
Age Analysis on Accruing Past-due Loans and Nonaccrual Loans [Abstract]
Loans	390,394	311,686
Nonaccrual	293	272
Commercial [Member] | Specialized [Member] | 30-89 Days Past Due [Member]
Age Analysis on Accruing Past-due Loans and Nonaccrual Loans [Abstract]
Loans	43	241
Commercial [Member] | Specialized [Member] | 90 Days or More Past Due [Member]
Age Analysis on Accruing Past-due Loans and Nonaccrual Loans [Abstract]
Loans	62	0
Commercial [Member] | General [Member]
Age Analysis on Accruing Past-due Loans and Nonaccrual Loans [Abstract]
Loans	452,776	518,309
Nonaccrual	5,564	5,489
Commercial [Member] | General [Member] | 30-89 Days Past Due [Member]
Age Analysis on Accruing Past-due Loans and Nonaccrual Loans [Abstract]
Loans	698	1,891
Commercial [Member] | General [Member] | 90 Days or More Past Due [Member]
Age Analysis on Accruing Past-due Loans and Nonaccrual Loans [Abstract]
Loans	149	149
Consumer [Member] | 1-4 Family Residential [Member]
Age Analysis on Accruing Past-due Loans and Nonaccrual Loans [Abstract]
Loans	387,167	360,315
Nonaccrual	2,313	1,595
Consumer [Member] | 1-4 Family Residential [Member] | 30-89 Days Past Due [Member]
Age Analysis on Accruing Past-due Loans and Nonaccrual Loans [Abstract]
Loans	1,998	2,089
Consumer [Member] | 1-4 Family Residential [Member] | 90 Days or More Past Due [Member]
Age Analysis on Accruing Past-due Loans and Nonaccrual Loans [Abstract]
Loans	410	906
Consumer [Member] | Auto Loans [Member]
Age Analysis on Accruing Past-due Loans and Nonaccrual Loans [Abstract]
Loans	239,397	205,840
Nonaccrual	0	0
Consumer [Member] | Auto Loans [Member] | 30-89 Days Past Due [Member]
Age Analysis on Accruing Past-due Loans and Nonaccrual Loans [Abstract]
Loans	330	738
Consumer [Member] | Auto Loans [Member] | 90 Days or More Past Due [Member]
Age Analysis on Accruing Past-due Loans and Nonaccrual Loans [Abstract]
Loans	23	38
Consumer [Member] | Other Consumer [Member]
Age Analysis on Accruing Past-due Loans and Nonaccrual Loans [Abstract]
Loans	69,079	67,595
Nonaccrual	46	51
Consumer [Member] | Other Consumer [Member] | 30-89 Days Past Due [Member]
Age Analysis on Accruing Past-due Loans and Nonaccrual Loans [Abstract]
Loans	729	481
Consumer [Member] | Other Consumer [Member] | 90 Days or More Past Due [Member]
Age Analysis on Accruing Past-due Loans and Nonaccrual Loans [Abstract]
Loans	69	119
Construction [Member]
Age Analysis on Accruing Past-due Loans and Nonaccrual Loans [Abstract]
Loans	143,453	94,494
Nonaccrual	166	0
Construction [Member] | 30-89 Days Past Due [Member]
Age Analysis on Accruing Past-due Loans and Nonaccrual Loans [Abstract]
Loans	457	206
Construction [Member] | 90 Days or More Past Due [Member]
Age Analysis on Accruing Past-due Loans and Nonaccrual Loans [Abstract]
Loans	$ 0	$ 0