LOANS AND ALLOWANCE FOR CREDIT LOSSES - Schedule of Allowance for Credit Losses Activity (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 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 and Loans losses		1,400	13,200
Loans charged-off	(875)	(224)	(543)
Recoveries	26	22	212
Ending balance	32,770	21,948	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 and Loans losses	(504)	365	1,398
Loans charged-off	(7)	(43)	(68)
Recoveries	7		101
Ending balance	3,529	2,924	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 and Loans losses	(538)	(123)	2,034
Recoveries	1
Ending balance	4,198	2,578	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 and Loans losses	1,087	680	6,698
Loans charged-off	(758)
Recoveries			1
Ending balance	16,109	9,761	15,780
Farmland
Allowance for credit losses:
Beginning balance	1,220	570	570
Impact of adopting ASC 326		26	26
Provision for credit losses and Loans losses	(163)	196	624
Ending balance	1,057	792	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 and Loans losses	13	(250)	1,915
Loans charged-off		(59)	(68)
Recoveries		1	2
Ending balance	6,326	4,156	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 and Loans losses	133	(170)	4
Ending balance	496	189	363
Consumer
Allowance for credit losses:
Beginning balance	929	602	602
Impact of adopting ASC 326		72	72
Provision for credit losses and Loans losses	(29)	85	373
Loans charged-off	(61)	(73)	(155)
Recoveries	4	7	37
Ending balance	843	693	929
Agricultural
Allowance for credit losses:
Beginning balance	239	197	197
Impact of adopting ASC 326		73	73
Provision for credit losses and Loans losses	(31)	11	(33)
Loans charged-off			(18)
Recoveries			20
Ending balance	208	281	239
Overdrafts
Allowance for credit losses:
Beginning balance	7	12	12
Impact of adopting ASC 326		(9)	(9)
Provision for credit losses and Loans losses	32	35	187
Loans charged-off	(49)	(49)	(234)
Recoveries	14	14	51
Ending balance	$ 4	3	$ 7
Unallocated
Allowance for credit losses:
Provision for credit losses and Loans losses		571
Ending balance		$ 571