ALLOWANCE FOR LOAN LOSSES AND CREDIT QUALITY - Aging Of The Recorded Investment In Past Due Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans Not Past Due	$ 4,575,317	$ 4,045,634
Nonaccrual	13,478	18,675
Total Past Due and Nonaccrual	14,607	20,194
Total ending loans balance	4,589,924	4,065,828
Financial Asset, 30 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due	1,110	1,474
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due	19	45
Closed End First Mortgage Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans Not Past Due		174,902
Nonaccrual		827
Total Past Due and Nonaccrual		1,971
Total ending loans balance		176,873
Closed End First Mortgage Loans [Member] | Financial Asset, 30 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due		1,099
Closed End First Mortgage Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due		45
Commercial and Industrial Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total ending loans balance	1,837,747	1,426,826
Commercial and Industrial Loans [Member] | Working Capital Lines of Credit Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans Not Past Due	591,549	703,737
Nonaccrual	1,050	6,236
Total Past Due and Nonaccrual	1,091	6,246
Total ending loans balance	592,640	709,983
Commercial and Industrial Loans [Member] | Working Capital Lines of Credit Loans [Member] | Financial Asset, 30 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due	41	10
Commercial and Industrial Loans [Member] | Working Capital Lines of Credit Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due	0	0
Commercial and Industrial Loans [Member] | Non-working Capital Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans Not Past Due	1,239,596	710,557
Nonaccrual	5,508	6,282
Total Past Due and Nonaccrual	5,511	6,286
Total ending loans balance	1,245,107	716,843
Commercial and Industrial Loans [Member] | Non-working Capital Loans [Member] | Financial Asset, 30 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due	3	4
Commercial and Industrial Loans [Member] | Non-working Capital Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due	0	0
Commercial Real Estate and Multi-family Residential Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total ending loans balance	1,857,820	1,670,840
Commercial Real Estate and Multi-family Residential Loans [Member] | Construction and Land Development Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans Not Past Due	392,078	286,534
Nonaccrual	0	0
Total Past Due and Nonaccrual	0	0
Total ending loans balance	392,078	286,534
Commercial Real Estate and Multi-family Residential Loans [Member] | Construction and Land Development Loans [Member] | Financial Asset, 30 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due	0	0
Commercial Real Estate and Multi-family Residential Loans [Member] | Construction and Land Development Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due	0	0
Commercial Real Estate and Multi-family Residential Loans [Member] | Owner Occupied Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans Not Past Due	614,264	569,303
Nonaccrual	5,143	4,056
Total Past Due and Nonaccrual	5,143	4,056
Total ending loans balance	619,407	573,359
Commercial Real Estate and Multi-family Residential Loans [Member] | Owner Occupied Loans [Member] | Financial Asset, 30 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due	0	0
Commercial Real Estate and Multi-family Residential Loans [Member] | Owner Occupied Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due	0	0
Commercial Real Estate and Multi-family Residential Loans [Member] | Nonowner Occupied Loans
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans Not Past Due	567,009	570,687
Nonaccrual	0	0
Total Past Due and Nonaccrual	18	0
Total ending loans balance	567,027	570,687
Commercial Real Estate and Multi-family Residential Loans [Member] | Nonowner Occupied Loans | Financial Asset, 30 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due	18	0
Commercial Real Estate and Multi-family Residential Loans [Member] | Nonowner Occupied Loans | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due	0	0
Commercial Real Estate and Multi-family Residential Loans [Member] | Multifamily Loans
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans Not Past Due	279,308	240,260
Nonaccrual	0	0
Total Past Due and Nonaccrual	0	0
Total ending loans balance	279,308	240,260
Commercial Real Estate and Multi-family Residential Loans [Member] | Multifamily Loans | Financial Asset, 30 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due	0	0
Commercial Real Estate and Multi-family Residential Loans [Member] | Multifamily Loans | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due	0	0
Agri-business and Agricultural Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total ending loans balance	338,164	379,631
Agri-business and Agricultural Loans [Member] | Loans Secured By Farmland
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans Not Past Due	150,020	173,959
Nonaccrual	428	430
Total Past Due and Nonaccrual	428	430
Total ending loans balance	150,448	174,389
Agri-business and Agricultural Loans [Member] | Loans Secured By Farmland | Financial Asset, 30 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due	0	0
Agri-business and Agricultural Loans [Member] | Loans Secured By Farmland | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due	0	0
Agri-business and Agricultural Loans [Member] | Loans For Agricultural Production
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans Not Past Due	187,716	205,228
Nonaccrual	0	14
Total Past Due and Nonaccrual	0	14
Total ending loans balance	187,716	205,242
Agri-business and Agricultural Loans [Member] | Loans For Agricultural Production | Financial Asset, 30 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due	0	0
Agri-business and Agricultural Loans [Member] | Loans For Agricultural Production | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due	0	0
Agri-business and Agricultural Loans [Member] | Other Commercial Loans
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans Not Past Due	97,428	112,166
Nonaccrual	0	0
Total Past Due and Nonaccrual	0	0
Total ending loans balance	97,428	112,166
Agri-business and Agricultural Loans [Member] | Other Commercial Loans | Financial Asset, 30 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due	0	0
Agri-business and Agricultural Loans [Member] | Other Commercial Loans | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due	0	0
Consumer 1-4 Family Mortgage Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total ending loans balance	353,724	377,999
Consumer 1-4 Family Mortgage Loans [Member] | Closed End First Mortgage Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans Not Past Due	168,835
Nonaccrual	640
Total Past Due and Nonaccrual	1,472
Total ending loans balance	170,307	176,873
Consumer 1-4 Family Mortgage Loans [Member] | Closed End First Mortgage Loans [Member] | Financial Asset, 30 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due	813
Consumer 1-4 Family Mortgage Loans [Member] | Closed End First Mortgage Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due	19
Consumer 1-4 Family Mortgage Loans [Member] | Open End and Junior Lien Loans
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans Not Past Due	171,669	187,255
Nonaccrual	684	761
Total Past Due and Nonaccrual	783	949
Total ending loans balance	172,452	188,204
Consumer 1-4 Family Mortgage Loans [Member] | Open End and Junior Lien Loans | Financial Asset, 30 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due	99	188
Consumer 1-4 Family Mortgage Loans [Member] | Open End and Junior Lien Loans | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due	0	0
Consumer 1-4 Family Mortgage Loans [Member] | Residential Construction and Land Development Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans Not Past Due	10,940	12,870
Nonaccrual	25	52
Total Past Due and Nonaccrual	25	52
Total ending loans balance	10,965	12,922
Consumer 1-4 Family Mortgage Loans [Member] | Residential Construction and Land Development Loans [Member] | Financial Asset, 30 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due	0	0
Consumer 1-4 Family Mortgage Loans [Member] | Residential Construction and Land Development Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due	0	0
Consumer 1-4 Family Mortgage Loans [Member] | Other consumer loans
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans Not Past Due	104,905	98,176
Nonaccrual	0	17
Total Past Due and Nonaccrual	136	190
Total ending loans balance	105,041	98,366
Consumer 1-4 Family Mortgage Loans [Member] | Other consumer loans | Financial Asset, 30 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due	136	173
Consumer 1-4 Family Mortgage Loans [Member] | Other consumer loans | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due	$ 0	$ 0