ALLOWANCE FOR CREDIT LOSSES - Loans by risk grades, loan class and vintage (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Financing Receivable, Recorded Investment [Line Items]
2021	$ 269,133
2020	681,857	$ 856,746
2019	492,636	512,418
2018	415,753	452,751
2017	221,196	231,935
2016		114,252
Prior	407,540	338,342
Revolving Loans	397,746	403,288
Converted revolving loan	17,927	26,938
Total Loans	2,903,788	2,936,670
Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Total Loans	756,707	742,957
Commercial real estate:
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,072,263	1,041,998
Construction and development
Financing Receivable, Recorded Investment [Line Items]
Total Loans	464,091	522,705
1-4 family residential
Financing Receivable, Recorded Investment [Line Items]
Total Loans	224,880	239,872
Multifamily residential
Financing Receivable, Recorded Investment [Line Items]
Total Loans	271,719	258,346
Consumer
Financing Receivable, Recorded Investment [Line Items]
Total Loans	32,767	33,884
Agriculture
Financing Receivable, Recorded Investment [Line Items]
Total Loans	6,974	8,670
Other:
Financing Receivable, Recorded Investment [Line Items]
Total Loans	74,387	88,238
Loans by risk grades
Financing Receivable, Recorded Investment [Line Items]
Total Loans	2,903,788	2,936,670
Loans by risk grades | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
2021	165,037
2020	224,735	350,698
2019	77,866	83,764
2018	48,440	53,183
2017	11,952	13,176
2016		8,369
Prior	12,161	5,453
Revolving Loans	206,375	218,310
Converted revolving loan	10,141	10,004
Total Loans	756,707	742,957
Loans by risk grades | Commercial real estate:
Financing Receivable, Recorded Investment [Line Items]
2021	43,076
2020	247,114	262,072
2019	234,952	223,710
2018	217,552	206,229
2017	135,785	138,900
2016		69,527
Prior	135,789	87,828
Revolving Loans	53,439	39,345
Converted revolving loan	4,556	14,387
Total Loans	1,072,263	1,041,998
Loans by risk grades | Construction and development
Financing Receivable, Recorded Investment [Line Items]
2021	35,351
2020	144,641	165,894
2019	138,120	163,896
2018	50,351	100,841
2017	29,662	30,678
2016		6,707
Prior	4,959	889
Revolving Loans	60,521	53,800
Converted revolving loan	486
Total Loans	464,091	522,705
Loans by risk grades | 1-4 family residential
Financing Receivable, Recorded Investment [Line Items]
2021	5,181
2020	25,246	28,550
2019	34,127	31,512
2018	42,759	49,772
2017	31,649	36,541
2016		26,018
Prior	77,815	58,337
Revolving Loans	5,972	7,004
Converted revolving loan	2,131	2,138
Total Loans	224,880	239,872
Loans by risk grades | Multifamily residential
Financing Receivable, Recorded Investment [Line Items]
2021	11,177
2020	20,734	20,823
2019	3,071	3,119
2018	52,102	36,971
2017	10,376	10,655
2016		2,153
Prior	174,178	184,539
Revolving Loans	81	86
Total Loans	271,719	258,346
Loans by risk grades | Consumer
Financing Receivable, Recorded Investment [Line Items]
2021	2,607
2020	6,609	8,937
2019	2,461	3,073
2018	1,580	1,855
2017	1,674	1,875
2016		146
Prior	80	23
Revolving Loans	17,335	17,573
Converted revolving loan	421	402
Total Loans	32,767	33,884
Loans by risk grades | Agriculture
Financing Receivable, Recorded Investment [Line Items]
2021	385
2020	1,791	3,937
2019	60	105
2018	134	338
2017	78	86
2016		16
Prior	35	23
Revolving Loans	4,299	4,158
Converted revolving loan	192	7
Total Loans	6,974	8,670
Loans by risk grades | Other:
Financing Receivable, Recorded Investment [Line Items]
2021	6,319
2020	10,987	15,835
2019	1,979	3,239
2018	2,835	3,562
2017	20	24
2016		1,316
Prior	2,523	1,250
Revolving Loans	49,724	63,012
Total Loans	74,387	88,238
Pass
Financing Receivable, Recorded Investment [Line Items]
2021	269,050
2020	676,938	852,986
2019	477,175	496,257
2018	390,839	427,345
2017	210,140	219,341
2016		110,309
Prior	398,438	331,092
Revolving Loans	377,578	384,354
Converted revolving loan	10,090	14,084
Total Loans	2,810,248	2,835,768
Pass | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
2021	165,037
2020	223,735	349,697
2019	75,534	81,131
2018	42,431	46,973
2017	11,942	13,161
2016		8,349
Prior	10,078	3,432
Revolving Loans	202,063	214,160
Converted revolving loan	3,810	3,562
Total Loans	734,630	720,465
Pass | Commercial real estate:
Financing Receivable, Recorded Investment [Line Items]
2021	43,076
2020	245,780	262,072
2019	222,588	210,954
2018	202,685	196,630
2017	135,414	138,424
2016		68,468
Prior	133,357	84,453
Revolving Loans	37,718	30,020
Converted revolving loan	4,556	9,482
Total Loans	1,025,174	1,000,503
Pass | Construction and development
Financing Receivable, Recorded Investment [Line Items]
2021	35,351
2020	144,641	165,894
2019	137,884	163,658
2018	47,309	92,455
2017	19,280	20,146
2016		6,707
Prior	4,343	273
Revolving Loans	60,521	53,800
Converted revolving loan	486
Total Loans	449,815	502,933
Pass | 1-4 family residential
Financing Receivable, Recorded Investment [Line Items]
2021	5,098
2020	23,698	27,002
2019	33,598	30,978
2018	41,763	48,561
2017	31,356	34,970
2016		24,386
Prior	75,089	57,122
Revolving Loans	5,972	7,004
Converted revolving loan	625	631
Total Loans	217,199	230,654
Pass | Multifamily residential
Financing Receivable, Recorded Investment [Line Items]
2021	11,177
2020	20,734	20,823
2019	3,071	3,119
2018	52,102	36,971
2017	10,376	10,655
2016		2,153
Prior	174,178	184,539
Revolving Loans	81	86
Total Loans	271,719	258,346
Pass | Consumer
Financing Receivable, Recorded Investment [Line Items]
2021	2,607
2020	6,609	8,937
2019	2,461	3,073
2018	1,580	1,855
2017	1,674	1,875
2016		146
Prior	80	23
Revolving Loans	17,245	17,573
Converted revolving loan	421	402
Total Loans	32,677	33,884
Pass | Agriculture
Financing Receivable, Recorded Investment [Line Items]
2021	385
2020	1,791	3,937
2019	60	105
2018	134	338
2017	78	86
2016		16
Prior	13
Revolving Loans	4,254	4,108
Converted revolving loan	192	7
Total Loans	6,907	8,597
Pass | Other:
Financing Receivable, Recorded Investment [Line Items]
2021	6,319
2020	9,950	14,624
2019	1,979	3,239
2018	2,835	3,562
2017	20	24
2016		84
Prior	1,300	1,250
Revolving Loans	49,724	57,603
Total Loans	72,127	80,386
Special Mention
Financing Receivable, Recorded Investment [Line Items]
2020		1,548
2019	889	1,224
2018	29	33
2016		1,617
Prior	1,725	1,390
Revolving Loans	7,865	3,371
Converted revolving loan		4,905
Total Loans	10,508	14,088
Special Mention | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
2018	29	33
Revolving Loans	3,144	3,371
Total Loans	3,173	3,404
Special Mention | Commercial real estate:
Financing Receivable, Recorded Investment [Line Items]
2019	889	1,224
Prior	154	1,390
Revolving Loans	4,721
Converted revolving loan		4,905
Total Loans	5,764	7,519
Special Mention | 1-4 family residential
Financing Receivable, Recorded Investment [Line Items]
2020		1,548
2016		1,617
Prior	1,571
Total Loans	1,571	3,165
Substandard
Financing Receivable, Recorded Investment [Line Items]
2021	83
2020	4,919	2,212
2019	14,572	14,937
2018	24,885	25,373
2017	11,056	12,594
2016		2,326
Prior	7,377	5,860
Revolving Loans	12,303	15,563
Converted revolving loan	7,837	7,949
Total Loans	83,032	86,814
Substandard | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
2020	1,000	1,001
2019	2,332	2,633
2018	5,980	6,177
2017	10	15
2016		20
Prior	2,083	2,021
Revolving Loans	1,168	779
Converted revolving loan	6,331	6,442
Total Loans	18,904	19,088
Substandard | Commercial real estate:
Financing Receivable, Recorded Investment [Line Items]
2020	1,334
2019	11,475	11,532
2018	14,867	9,599
2017	371	476
2016		1,059
Prior	2,278	1,985
Revolving Loans	11,000	9,325
Total Loans	41,325	33,976
Substandard | Construction and development
Financing Receivable, Recorded Investment [Line Items]
2019	236	238
2018	3,042	8,386
2017	10,382	10,532
Prior	616	616
Total Loans	14,276	19,772
Substandard | 1-4 family residential
Financing Receivable, Recorded Investment [Line Items]
2021	83
2020	1,548
2019	529	534
2018	996	1,211
2017	293	1,571
2016		15
Prior	1,155	1,215
Converted revolving loan	1,506	1,507
Total Loans	6,110	6,053
Substandard | Consumer
Financing Receivable, Recorded Investment [Line Items]
Revolving Loans	90
Total Loans	90
Substandard | Agriculture
Financing Receivable, Recorded Investment [Line Items]
Prior	22	23
Revolving Loans	45	50
Total Loans	67	73
Substandard | Other:
Financing Receivable, Recorded Investment [Line Items]
2020	1,037	1,211
2016		1,232
Prior	1,223
Revolving Loans		5,409
Total Loans	2,260	7,852
Loss or Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total Loans	$ 0	$ 0