ALLOWANCE FOR CREDIT LOSSES - Loans by risk grades and loan class (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Amortized cost of loans by loan type
Total loans	$ 2,947,767	$ 2,646,673
Loans by risk grades
Amortized cost of loans by loan type
Total loans	2,947,767	2,646,673
Pass
Amortized cost of loans by loan type
Total loans	2,874,412	2,582,970
Special Mention
Amortized cost of loans by loan type
Total loans	3,245	34,742
Substandard
Amortized cost of loans by loan type
Total loans	70,110	28,961
Commercial and industrial
Amortized cost of loans by loan type
Total loans	837,667	527,607
Commercial and industrial | Loans by risk grades
Amortized cost of loans by loan type
Total loans	837,667	527,607
Commercial and industrial | Pass
Amortized cost of loans by loan type
Total loans	819,124	513,417
Commercial and industrial | Special Mention
Amortized cost of loans by loan type
Total loans	546	2,963
Commercial and industrial | Substandard
Amortized cost of loans by loan type
Total loans	17,997	11,227
Commercial real estate
Amortized cost of loans by loan type
Total loans	908,027	900,746
Commercial real estate | Loans by risk grades
Amortized cost of loans by loan type
Total loans	908,027	900,746
Commercial real estate | Pass
Amortized cost of loans by loan type
Total loans	878,204	876,207
Commercial real estate | Special Mention
Amortized cost of loans by loan type
Total loans	1,890	18,570
Commercial real estate | Substandard
Amortized cost of loans by loan type
Total loans	27,933	5,969
Construction and development
Amortized cost of loans by loan type
Total loans	552,879	527,812
Construction and development | Loans by risk grades
Amortized cost of loans by loan type
Total loans	552,879	527,812
Construction and development | Pass
Amortized cost of loans by loan type
Total loans	540,341	515,247
Construction and development | Special Mention
Amortized cost of loans by loan type
Total loans		12,565
Construction and development | Substandard
Amortized cost of loans by loan type
Total loans	12,538
1-4 family residential
Amortized cost of loans by loan type
Total loans	272,253	280,192
1-4 family residential | Loans by risk grades
Amortized cost of loans by loan type
Total loans	272,253	280,192
1-4 family residential | Pass
Amortized cost of loans by loan type
Total loans	266,154	274,731
1-4 family residential | Special Mention
Amortized cost of loans by loan type
Total loans	809	594
1-4 family residential | Substandard
Amortized cost of loans by loan type
Total loans	5,290	4,867
Multifamily residential
Amortized cost of loans by loan type
Total loans	255,273	277,209
Multifamily residential | Loans by risk grades
Amortized cost of loans by loan type
Total loans	255,273	277,209
Multifamily residential | Pass
Amortized cost of loans by loan type
Total loans	255,273	277,209
Consumer
Amortized cost of loans by loan type
Total loans	36,338	36,782
Consumer | Loans by risk grades
Amortized cost of loans by loan type
Total loans	36,338	36,782
Consumer | Pass
Amortized cost of loans by loan type
Total loans	36,335	36,566
Consumer | Substandard
Amortized cost of loans by loan type
Total loans	3	216
Agriculture
Amortized cost of loans by loan type
Total loans	7,795	9,812
Agriculture | Loans by risk grades
Amortized cost of loans by loan type
Total loans	7,795	9,812
Agriculture | Pass
Amortized cost of loans by loan type
Total loans	7,718	9,733
Agriculture | Special Mention
Amortized cost of loans by loan type
Total loans		50
Agriculture | Substandard
Amortized cost of loans by loan type
Total loans	77	29
Other
Amortized cost of loans by loan type
Total loans	77,535	86,513
Other | Loans by risk grades
Amortized cost of loans by loan type
Total loans	77,535	86,513
Other | Pass
Amortized cost of loans by loan type
Total loans	71,263	79,860
Other | Substandard
Amortized cost of loans by loan type
Total loans	$ 6,272	$ 6,653