LOANS AND ALLOWANCE FOR CREDIT LOSSES - Schedule of Allowance for Credit Losses Activity (Details) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Allowance for credit losses:
Beginning balance	$ 33,619	$ 16,202	$ 16,202
Impact of adopting ASC 326		4,548	4,548
Provision for credit losses	(1,700)		13,200
Loans charged-off	(1,402)	384	(543)
Recoveries	104	191	212
Ending balance	30,621		33,619
Commercial and industrial
Allowance for credit losses:
Beginning balance	4,033	2,056	2,056
Impact of adopting ASC 326		546	546
Provision for credit losses	(268)	1,366	1,398
Loans charged-off	(300)	(43)	(68)
Recoveries	15	93	101
Ending balance	3,480	4,018	4,033
Construction and development
Allowance for credit losses:
Beginning balance	4,735	2,378	2,378
Impact of adopting ASC 326		323	323
Provision for credit losses	(774)	2,228	2,034
Recoveries	1
Ending balance	3,962	4,929	4,735
Commercial real estate
Allowance for credit losses:
Beginning balance	15,780	6,853	6,853
Impact of adopting ASC 326		2,228	2,228
Provision for credit losses	670	6,613	6,698
Loans charged-off	(816)
Recoveries	11	1	1
Ending balance	14,305	15,695	15,780
Farmland
Allowance for credit losses:
Beginning balance	1,220	570	570
Impact of adopting ASC 326		26	26
Provision for credit losses	365	694	624
Ending balance	1,585	1,290	1,220
1-4 family residential
Allowance for credit losses:
Beginning balance	6,313	3,125	3,125
Impact of adopting ASC 326		1,339	1,339
Provision for credit losses	(559)	1,778	1,915
Loans charged-off		(59)	(68)
Recoveries		2	2
Ending balance	5,754	6,185	6,313
Multi-family residential
Allowance for credit losses:
Beginning balance	363	409	409
Impact of adopting ASC 326		(50)	(50)
Provision for credit losses	213	34	4
Ending balance	576	325	363
Consumer
Allowance for credit losses:
Beginning balance	929	602	602
Impact of adopting ASC 326		72	72
Provision for credit losses	(61)	407	373
Loans charged-off	(113)	(136)	(155)
Recoveries	32	30	37
Ending balance	787	975	929
Agricultural
Allowance for credit losses:
Beginning balance	239	197	197
Impact of adopting ASC 326		73	73
Provision for credit losses	(73)	59	(33)
Loans charged-off		(18)	(18)
Recoveries		20	20
Ending balance	166	331	239
Overdrafts
Allowance for credit losses:
Beginning balance	7	12	12
Impact of adopting ASC 326		(9)	(9)
Provision for credit losses	127	89	187
Loans charged-off	(173)	(128)	(234)
Recoveries	45	45	51
Ending balance	$ 6	9	$ 7
Unallocated
Allowance for credit losses:
Provision for credit losses		13,200
Ending balance		$ 33,757