LOANS HELD FOR INVESTMENT, Summary of Loans by Category (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2021 USD ($) Category	Jun. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)
Summary of Loans by Category [Abstract]
Loans, gross	$ 2,429,041		$ 2,221,583
Allowance for loan losses	(42,768)	$ (42,963)	(45,553)	$ (46,076)	$ (40,635)	$ (24,197)
Loans, net	2,386,273		2,176,030
Commercial Real Estate [Member]
Summary of Loans by Category [Abstract]
Loans, gross	746,775		663,344
Allowance for loan losses	$ (18,248)	(17,288)	(18,962)	(18,264)	(15,156)	(5,049)
Commercial [Member]
Summary of Loans by Category [Abstract]
Number of sub-categories of loans | Category	2
Commercial [Member] | Specialized [Member]
Summary of Loans by Category [Abstract]
Loans, gross	$ 390,394		311,686
Allowance for loan losses	(4,231)	(4,823)	(5,760)	(6,304)	(6,614)	(2,287)
Commercial [Member] | General [Member]
Summary of Loans by Category [Abstract]
Loans, gross	452,776		518,309
Allowance for loan losses	(8,171)	(8,948)	(9,227)	(9,989)	(9,293)	(9,609)
Consumer [Member] | 1-4 Family Residential [Member]
Summary of Loans by Category [Abstract]
Loans, gross	387,167		360,315
Allowance for loan losses	(5,201)	(5,064)	(4,646)	(4,684)	(2,926)	(2,093)
Consumer [Member] | Auto Loans [Member]
Summary of Loans by Category [Abstract]
Loans, gross	239,397		205,840
Allowance for loan losses	(3,803)	(3,815)	(4,226)	(4,233)	(3,939)	(3,385)
Consumer [Member] | Other Consumer [Member]
Summary of Loans by Category [Abstract]
Loans, gross	69,079		67,595
Allowance for loan losses	(1,402)	(1,434)	(1,671)	(1,727)	(1,640)	(1,341)
Construction [Member]
Summary of Loans by Category [Abstract]
Loans, gross	143,453		94,494
Allowance for loan losses	$ (1,712)	$ (1,591)	$ (1,061)	$ (875)	$ (1,067)	$ (433)