LOANS AND ALLOWANCE FOR CREDIT LOSSES - Summary of Credit Exposure in Company Loan Portfolio (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2021	$ 318,569	$ 628,756
Credit Exposure 2020	456,548	286,256
Credit Exposure 2019	248,182	212,899
Credit Exposure 2018	200,374	163,831
Credit Exposure 2017	146,192	174,558
Credit Exposure Prior	419,167	274,903
Revolving Loans Amortized Cost	123,335	125,616
Total	1,912,367	1,866,819
Credit Exposure 2021.Charge - offs	49	243
Credit Exposure 2020.Charge - offs	(6)	(63)
Credit Exposure 2019.Charge - offs	(55)	(92)
Credit Exposure 2018.Charge - offs	(16)
Credit Exposure 2017.Charge - offs	(471)	(12)
Credit Exposure Prior.Charge - offs	(271)	(65)
Credit Exposure Revolving Loans Amortized Cost.Charge - offs	(7)	(25)
Total	(875)	(543)
Credit Exposure 2021, Recoveries	14	49
Credit Exposure 2020, Recoveries		2
Credit Exposure 2019, Recoveries		55
Credit Exposure 2018, Recoveries		8
Credit Exposure 2017, Recoveries	1	24
Credit Exposure Prior, Recoveries	5	30
Credit Exposure Revolving Loans Amortized Cost, Recoveries	6	44
Total	26	212
Credit Exposure 2021,Current period net	(35)	(194)
Credit Exposure 2020,Current period net	(6)	(61)
Credit Exposure 2019,Current period net	(55)	(37)
Credit Exposure 2018,Current period net	(16)	(35)
Credit Exposure 2017,Current period net	(470)	12
Credit Exposure Prior,Current period net	(266)	(35)
Credit Exposure Revolving Loans Amortized Cost,Current period net	(1)	19
Total	(849)	(331)
Credit Exposure 2020.Charge - offs	(49)	(243)
Pass
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2021	318,154	628,236
Credit Exposure 2020	448,412	281,239
Credit Exposure 2019	238,230	205,907
Credit Exposure 2018	184,135	148,724
Credit Exposure 2017	129,905	157,326
Credit Exposure Prior	396,745	264,245
Revolving Loans Amortized Cost	123,335	125,616
Total	1,838,916	1,811,293
Special Mention
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2021	415	496
Credit Exposure 2020	730	2,918
Credit Exposure 2019	1,791	3,773
Credit Exposure 2018	4,120	5,922
Credit Exposure 2017	2,024	7,048
Credit Exposure Prior	2,190	652
Total	11,270	20,809
Substandard
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2020	7,362	923
Credit Exposure 2019	7,568	2,565
Credit Exposure 2018	11,398	4,963
Credit Exposure 2017	13,991	5,192
Credit Exposure Prior	18,479	8,369
Total	58,798	22,012
Nonaccrual
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2021		24
Credit Exposure 2020	44	1,176
Credit Exposure 2019	593	654
Credit Exposure 2018	721	4,222
Credit Exposure 2017	272	4,992
Credit Exposure Prior	1,753	1,637
Total	3,383	12,705
Commercial and industrial
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2021	190,664	278,811
Credit Exposure 2020	117,882	30,989
Credit Exposure 2019	26,522	13,635
Credit Exposure 2018	12,471	8,456
Credit Exposure 2017	7,091	7,512
Credit Exposure Prior	21,918	16,294
Revolving Loans Amortized Cost	83,943	90,074
Total	460,491	445,771
Credit Exposure 2019.Charge - offs		(43)
Credit Exposure Revolving Loans Amortized Cost.Charge - offs	(7)	(25)
Total	(7)	(68)
Credit Exposure 2019, Recoveries		43
Credit Exposure Prior, Recoveries	1	14
Credit Exposure Revolving Loans Amortized Cost, Recoveries	6	44
Total	7	101
Credit Exposure Prior,Current period net	1	14
Credit Exposure Revolving Loans Amortized Cost,Current period net	(1)	19
Total		33
Commercial and industrial | Pass
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2021	190,664	278,687
Credit Exposure 2020	117,479	30,563
Credit Exposure 2019	26,166	12,860
Credit Exposure 2018	12,168	4,366
Credit Exposure 2017	6,998	6,131
Credit Exposure Prior	21,873	16,294
Revolving Loans Amortized Cost	83,943	90,074
Total	459,291	438,975
Commercial and industrial | Special Mention
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2021		124
Credit Exposure 2020	113	119
Credit Exposure 2019		222
Credit Exposure 2018		4,040
Credit Exposure 2017	34	1,324
Total	147	5,829
Commercial and industrial | Substandard
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2020	290	307
Credit Exposure 2019	65	540
Credit Exposure 2018	230	50
Credit Exposure 2017	49	43
Credit Exposure Prior	31
Total	665	940
Commercial and industrial | Nonaccrual
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2019	291	13
Credit Exposure 2018	73
Credit Exposure 2017	10	14
Credit Exposure Prior	14
Total	388	27
Construction and development
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2021	30,281	118,946
Credit Exposure 2020	105,473	77,535
Credit Exposure 2019	55,915	26,217
Credit Exposure 2018	25,055	25,514
Credit Exposure 2017	20,412	8,422
Credit Exposure Prior	17,829	10,507
Revolving Loans Amortized Cost	2,921	3,266
Total	257,886	270,407
Credit Exposure Prior, Recoveries	1
Total	1
Credit Exposure Prior,Current period net	1
Total	1
Construction and development | Pass
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2021	30,281	118,590
Credit Exposure 2020	105,473	76,926
Credit Exposure 2019	50,592	26,212
Credit Exposure 2018	25,051	24,524
Credit Exposure 2017	19,434	7,742
Credit Exposure Prior	17,829	10,507
Revolving Loans Amortized Cost	2,921	3,266
Total	251,581	267,767
Construction and development | Special Mention
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2021		356
Credit Exposure 2018		990
Credit Exposure 2017	978
Total	978	1,346
Construction and development | Substandard
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2020		609
Credit Exposure 2019	5,093	5
Credit Exposure 2018	4
Credit Exposure 2017		680
Total	5,097	1,294
Construction and development | Nonaccrual
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2019	230
Total	230
Commercial real estate
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2021	50,856	91,819
Credit Exposure 2020	104,445	84,609
Credit Exposure 2019	78,474	95,245
Credit Exposure 2018	93,517	82,231
Credit Exposure 2017	75,949	101,884
Credit Exposure Prior	220,074	132,538
Revolving Loans Amortized Cost	7,164	5,890
Total	630,479	594,216
Credit Exposure 2019.Charge - offs	(17)
Credit Exposure 2017.Charge - offs	(470)
Credit Exposure Prior.Charge - offs	(271)
Total	(758)
Credit Exposure Prior, Recoveries		1
Total		1
Credit Exposure 2019,Current period net	(17)
Credit Exposure 2017,Current period net	(470)
Credit Exposure Prior,Current period net	(271)	1
Total	(758)	1
Commercial real estate | Pass
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2021	50,441	91,819
Credit Exposure 2020	96,823	80,753
Credit Exposure 2019	74,450	89,542
Credit Exposure 2018	78,078	72,311
Credit Exposure 2017	61,686	86,946
Credit Exposure Prior	199,507	123,463
Revolving Loans Amortized Cost	7,164	5,890
Total	568,149	550,724
Commercial real estate | Special Mention
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2021	415
Credit Exposure 2020	550	2,716
Credit Exposure 2019	1,621	3,542
Credit Exposure 2018	4,112	849
Credit Exposure 2017	841	5,724
Credit Exposure Prior	1,880	449
Total	9,419	13,280
Commercial real estate | Substandard
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2020	7,072
Credit Exposure 2019	2,403	2,010
Credit Exposure 2018	11,155	4,913
Credit Exposure 2017	13,216	4,445
Credit Exposure Prior	18,301	8,240
Total	52,147	19,608
Commercial real estate | Nonaccrual
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2020		1,140
Credit Exposure 2019		151
Credit Exposure 2018	172	4,158
Credit Exposure 2017	206	4,769
Credit Exposure Prior	386	386
Total	764	10,604
Farmland
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2021	6,131	17,444
Credit Exposure 2020	14,242	12,668
Credit Exposure 2019	11,905	10,327
Credit Exposure 2018	9,365	6,620
Credit Exposure 2017	5,939	9,904
Credit Exposure Prior	23,975	15,681
Revolving Loans Amortized Cost	5,310	5,864
Total	76,867	78,508
Farmland | Pass
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2021	6,131	17,444
Credit Exposure 2020	14,242	12,668
Credit Exposure 2019	11,905	10,327
Credit Exposure 2018	9,365	6,620
Credit Exposure 2017	5,939	9,904
Credit Exposure Prior	23,702	15,402
Revolving Loans Amortized Cost	5,310	5,864
Total	76,594	78,229
Farmland | Special Mention
Financing Receivable Recorded Investment [Line Items]
Credit Exposure Prior	33	35
Total	33	35
Farmland | Substandard
Financing Receivable Recorded Investment [Line Items]
Credit Exposure Prior	125	129
Total	125	129
Farmland | Nonaccrual
Financing Receivable Recorded Investment [Line Items]
Credit Exposure Prior	115	115
Total	115	115
1-4 family residential
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2021	20,613	87,578
Credit Exposure 2020	85,266	62,937
Credit Exposure 2019	60,209	52,413
Credit Exposure 2018	47,091	37,268
Credit Exposure 2017	33,660	44,021
Credit Exposure Prior	129,717	94,788
Revolving Loans Amortized Cost	12,986	10,091
Total	389,542	389,096
Credit Exposure 2017.Charge - offs		(9)
Credit Exposure Prior.Charge - offs		(59)
Total		(68)
Credit Exposure Prior, Recoveries		2
Total		2
Credit Exposure 2017,Current period net		(9)
Credit Exposure Prior,Current period net		(57)
Total		(66)
1-4 family residential | Pass
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2021	20,613	87,578
Credit Exposure 2020	85,266	62,937
Credit Exposure 2019	60,095	52,087
Credit Exposure 2018	46,771	37,224
Credit Exposure 2017	33,492	43,858
Credit Exposure Prior	128,204	93,486
Revolving Loans Amortized Cost	12,986	10,091
Total	387,427	387,261
1-4 family residential | Special Mention
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2019	114
Credit Exposure 2017	132
Credit Exposure Prior	277	168
Total	523	168
1-4 family residential | Nonaccrual
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2019		326
Credit Exposure 2018	320	44
Credit Exposure 2017	36	163
Credit Exposure Prior	1,236	1,134
Total	1,592	1,667
Multi-family residential
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2021	11,979	5,889
Credit Exposure 2020	6,133	4,498
Credit Exposure 2019	4,463	3,617
Credit Exposure 2018	3,575	1,371
Credit Exposure 2017	1,328	1,737
Credit Exposure Prior	4,376	4,391
Revolving Loans Amortized Cost	236	198
Total	32,090	21,701
Multi-family residential | Pass
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2021	11,979	5,889
Credit Exposure 2020	6,133	4,498
Credit Exposure 2019	4,463	3,617
Credit Exposure 2018	3,575	1,371
Credit Exposure 2017	641	1,737
Credit Exposure Prior	4,376	4,391
Revolving Loans Amortized Cost	236	198
Total	31,403	21,701
Multi-family residential | Substandard
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2017	687
Total	687
Consumer and Overdrafts
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2021	7,655	24,780
Credit Exposure 2020	20,502	11,295
Credit Exposure 2019	9,106	9,509
Credit Exposure 2018	7,703	1,728
Credit Exposure 2017	1,316	736
Credit Exposure Prior	921	513
Revolving Loans Amortized Cost	2,904	2,825
Total	50,107	51,386
Credit Exposure 2021.Charge - offs	49	243
Credit Exposure 2020.Charge - offs	(6)	(63)
Credit Exposure 2019.Charge - offs	(38)	(31)
Credit Exposure 2018.Charge - offs	(16)	(43)
Credit Exposure 2017.Charge - offs	(1)	(3)
Credit Exposure Prior.Charge - offs		(6)
Total	(110)	(389)
Credit Exposure 2021, Recoveries	14	49
Credit Exposure 2020, Recoveries		2
Credit Exposure 2019, Recoveries		12
Credit Exposure 2018, Recoveries		8
Credit Exposure 2017, Recoveries	1	4
Credit Exposure Prior, Recoveries	3	13
Total	18	88
Credit Exposure 2021,Current period net	(35)	(194)
Credit Exposure 2020,Current period net	(6)	(61)
Credit Exposure 2019,Current period net	(38)	(19)
Credit Exposure 2018,Current period net	(16)	(35)
Credit Exposure 2017,Current period net		1
Credit Exposure Prior,Current period net	3	7
Total	(92)	(301)
Credit Exposure 2020.Charge - offs	(49)	(243)
Consumer and Overdrafts | Pass
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2021	7,655	24,740
Credit Exposure 2020	20,391	11,176
Credit Exposure 2019	8,978	9,369
Credit Exposure 2018	7,586	1,701
Credit Exposure 2017	1,297	735
Credit Exposure Prior	921	513
Revolving Loans Amortized Cost	2,904	2,825
Total	49,732	51,059
Consumer and Overdrafts | Special Mention
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2021		16
Credit Exposure 2020	67	83
Credit Exposure 2019	56	9
Credit Exposure 2018	8	7
Credit Exposure 2017	5
Total	136	115
Consumer and Overdrafts | Nonaccrual
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2021		24
Credit Exposure 2020	44	36
Credit Exposure 2019	72	131
Credit Exposure 2018	109	20
Credit Exposure 2017	14	1
Total	239	212
Agricultural
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2021	390	3,489
Credit Exposure 2020	2,605	1,725
Credit Exposure 2019	1,588	1,936
Credit Exposure 2018	1,597	643
Credit Exposure 2017	497	342
Credit Exposure Prior	357	191
Revolving Loans Amortized Cost	7,871	7,408
Total	14,905	15,734
Credit Exposure 2019.Charge - offs		(18)
Total		(18)
Credit Exposure 2017, Recoveries		20
Total		20
Credit Exposure 2019,Current period net		(18)
Credit Exposure 2017,Current period net		20
Total		2
Agricultural | Pass
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2021	390	3,489
Credit Exposure 2020	2,605	1,718
Credit Exposure 2019	1,581	1,893
Credit Exposure 2018	1,541	607
Credit Exposure 2017	418	273
Credit Exposure Prior	333	189
Revolving Loans Amortized Cost	7,871	7,408
Total	14,739	15,577
Agricultural | Special Mention
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2018		36
Credit Exposure 2017	34
Total	34	36
Agricultural | Substandard
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2020		7
Credit Exposure 2019	7	10
Credit Exposure 2018	9
Credit Exposure 2017	39	24
Credit Exposure Prior	22
Total	77	41
Agricultural | Nonaccrual
Financing Receivable Recorded Investment [Line Items]
Credit Exposure 2019		33
Credit Exposure 2018	47
Credit Exposure 2017	6	45
Credit Exposure Prior	2	2
Total	$ 55	$ 80