ALLOWANCE FOR CREDIT LOSSES - Loans by risk grades, loan class and vintage (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Financing Receivable, Recorded Investment [Line Items]
2020	$ 129,761
2019	590,472
2018	586,167
2017	318,247
2016	145,039
Prior	428,526
Revolving Loans	428,855
Converted revolving loan	51,344
Total Loans	2,678,411	$ 2,646,673
Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Total Loans	542,650	527,607
Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total Loans	904,395	900,746
Construction and development
Financing Receivable, Recorded Investment [Line Items]
Total Loans	558,343	527,812
1-4 family residential
Financing Receivable, Recorded Investment [Line Items]
Total Loans	276,142	280,192
Multi‑family residential
Financing Receivable, Recorded Investment [Line Items]
Total Loans	267,152	277,209
Consumer
Financing Receivable, Recorded Investment [Line Items]
Total Loans	38,133	36,782
Agriculture
Financing Receivable, Recorded Investment [Line Items]
Total Loans	7,520	9,812
Other
Financing Receivable, Recorded Investment [Line Items]
Total Loans	84,076	86,513
Loans by risk grades
Financing Receivable, Recorded Investment [Line Items]
Total Loans		2,646,673
Loans by risk grades | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
2020	17,767
2019	121,599
2018	68,024
2017	19,472
2016	12,820
Prior	12,094
Revolving Loans	275,325
Converted revolving loan	15,549
Total Loans	542,650	527,607
Loans by risk grades | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
2020	57,116
2019	215,619
2018	219,626
2017	139,631
2016	89,266
Prior	132,964
Revolving Loans	36,851
Converted revolving loan	13,322
Total Loans	904,395	900,746
Loans by risk grades | Construction and development
Financing Receivable, Recorded Investment [Line Items]
2020	35,419
2019	184,779
2018	197,735
2017	56,129
2016	8,477
Prior	35,240
Revolving Loans	40,564
Total Loans	558,343	527,812
Loans by risk grades | 1-4 family residential
Financing Receivable, Recorded Investment [Line Items]
2020	7,110
2019	36,508
2018	66,642
2017	49,413
2016	28,385
Prior	74,228
Revolving Loans	11,094
Converted revolving loan	2,762
Total Loans	276,142	280,192
Loans by risk grades | Multi‑family residential
Financing Receivable, Recorded Investment [Line Items]
2020	7,770
2019	8,527
2018	23,743
2017	50,750
2016	4,361
Prior	172,001
Total Loans	267,152	277,209
Loans by risk grades | Consumer
Financing Receivable, Recorded Investment [Line Items]
2020	3,020
2019	6,506
2018	3,443
2017	2,528
2016	323
Prior	416
Revolving Loans	19,689
Converted revolving loan	2,208
Total Loans	38,133	36,782
Loans by risk grades | Agriculture
Financing Receivable, Recorded Investment [Line Items]
2020	936
2019	1,701
2018	547
2017	162
2016	38
Prior	32
Revolving Loans	4,025
Converted revolving loan	79
Total Loans	7,520	9,812
Loans by risk grades | Other
Financing Receivable, Recorded Investment [Line Items]
2020	623
2019	15,233
2018	6,407
2017	162
2016	1,369
Prior	1,551
Revolving Loans	41,307
Converted revolving loan	17,424
Total Loans	84,076	86,513
Pass
Financing Receivable, Recorded Investment [Line Items]
Total Loans		2,582,970
Pass | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
2020	16,734
2019	120,547
2018	67,560
2017	19,418
2016	12,466
Prior	9,688
Revolving Loans	270,877
Converted revolving loan	11,585
Total Loans	528,875	513,417
Pass | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
2020	57,116
2019	213,693
2018	214,659
2017	139,415
2016	86,079
Prior	129,764
Revolving Loans	36,851
Converted revolving loan	2,322
Total Loans	879,899	876,207
Pass | Construction and development
Financing Receivable, Recorded Investment [Line Items]
2020	35,419
2019	184,260
2018	196,235
2017	45,597
2016	8,477
Prior	35,240
Revolving Loans	40,564
Total Loans	545,792	515,247
Pass | 1-4 family residential
Financing Receivable, Recorded Investment [Line Items]
2020	7,110
2019	35,961
2018	66,602
2017	49,164
2016	27,973
Prior	70,808
Revolving Loans	11,094
Converted revolving loan	1,277
Total Loans	269,989	274,731
Pass | Multi‑family residential
Financing Receivable, Recorded Investment [Line Items]
2020	7,770
2019	8,527
2018	23,743
2017	50,750
2016	4,361
Prior	172,001
Total Loans	267,152	277,209
Pass | Consumer
Financing Receivable, Recorded Investment [Line Items]
2020	3,020
2019	6,506
2018	3,443
2017	2,528
2016	323
Prior	411
Revolving Loans	19,689
Converted revolving loan	2,208
Total Loans	38,128	36,566
Pass | Agriculture
Financing Receivable, Recorded Investment [Line Items]
2020	936
2019	1,701
2018	547
2017	162
2016	38
Prior	5
Revolving Loans	3,975
Converted revolving loan	79
Total Loans	7,443	9,733
Pass | Other
Financing Receivable, Recorded Investment [Line Items]
2020	623
2019	15,233
2018	5,026
2017	162
2016	128
Prior	1,551
Revolving Loans	35,662
Converted revolving loan	17,424
Total Loans	75,809	79,860
Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total Loans		34,742
Special Mention | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
2020	33
2019	266
2017	15
Revolving Loans	436
Total Loans	750	2,963
Special Mention | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
2016	1,587
Converted revolving loan	11,000
Total Loans	12,587	18,570
Special Mention | Construction and development
Financing Receivable, Recorded Investment [Line Items]
Total Loans		12,565
Special Mention | 1-4 family residential
Financing Receivable, Recorded Investment [Line Items]
2018	40
2016	392
Prior	386
Total Loans	818	594
Special Mention | Agriculture
Financing Receivable, Recorded Investment [Line Items]
Total Loans		50
Substandard
Financing Receivable, Recorded Investment [Line Items]
Total Loans		28,961
Substandard | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
2020	1,000
2019	786
2018	464
2017	39
2016	354
Prior	2,406
Revolving Loans	4,012
Converted revolving loan	3,964
Total Loans	13,025	11,227
Substandard | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
2019	1,926
2018	4,967
2017	216
2016	1,600
Prior	3,200
Total Loans	11,909	5,969
Substandard | Construction and development
Financing Receivable, Recorded Investment [Line Items]
2019	519
2018	1,500
2017	10,532
Total Loans	12,551
Substandard | 1-4 family residential
Financing Receivable, Recorded Investment [Line Items]
2019	547
2017	249
2016	20
Prior	3,034
Converted revolving loan	1,485
Total Loans	5,335	4,867
Substandard | Consumer
Financing Receivable, Recorded Investment [Line Items]
Prior	5
Total Loans	5	216
Substandard | Agriculture
Financing Receivable, Recorded Investment [Line Items]
Prior	27
Revolving Loans	50
Total Loans	77	29
Substandard | Other
Financing Receivable, Recorded Investment [Line Items]
2018	1,381
2016	1,241
Revolving Loans	5,645
Total Loans	$ 8,267	$ 6,653