FAIR VALUE - Assets Measured at Fair Value on a Nonrecurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage servicing rights, net of valuation allowance	$ 4,200
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	6,765	$ 12,121
Other real estate owned		0
Total assets	6,765	12,121
Level 1 | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	0	0
Other real estate owned	0	0
Total assets	0	0
Level 2 | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	0	0
Other real estate owned	0	0
Total assets	0	0
Level 3 | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	6,765	12,121
Other real estate owned	0	0
Total assets	6,765	12,121
Commercial and Industrial Loans [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	5,082	9,499
Commercial and Industrial Loans [Member] | Working Capital Lines of Credit Loans [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	178	3,125
Commercial and Industrial Loans [Member] | Working Capital Lines of Credit Loans [Member] | Level 1 | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	0	0
Commercial and Industrial Loans [Member] | Working Capital Lines of Credit Loans [Member] | Level 2 | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	0	0
Commercial and Industrial Loans [Member] | Working Capital Lines of Credit Loans [Member] | Level 3 | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	178	3,125
Commercial and Industrial Loans [Member] | Non-working Capital Loans [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	4,904	6,374
Commercial and Industrial Loans [Member] | Non-working Capital Loans [Member] | Level 1 | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	0	0
Commercial and Industrial Loans [Member] | Non-working Capital Loans [Member] | Level 2 | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	0	0
Commercial and Industrial Loans [Member] | Non-working Capital Loans [Member] | Level 3 | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	4,904	6,374
Commercial Real Estate and Multi-family Residential Loans | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	1,211	1,493
Commercial Real Estate and Multi-family Residential Loans | Construction and Land Development Loans [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans		43
Commercial Real Estate and Multi-family Residential Loans | Construction and Land Development Loans [Member] | Level 1 | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans		0
Commercial Real Estate and Multi-family Residential Loans | Construction and Land Development Loans [Member] | Level 2 | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans		0
Commercial Real Estate and Multi-family Residential Loans | Construction and Land Development Loans [Member] | Level 3 | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans		43
Commercial Real Estate and Multi-family Residential Loans | Owner Occupied Loans [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	1,211	1,450
Commercial Real Estate and Multi-family Residential Loans | Owner Occupied Loans [Member] | Level 1 | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	0	0
Commercial Real Estate and Multi-family Residential Loans | Owner Occupied Loans [Member] | Level 2 | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	0	0
Commercial Real Estate and Multi-family Residential Loans | Owner Occupied Loans [Member] | Level 3 | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	1,211	1,450
Agribusiness and Agricultural | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	61	57
Agribusiness and Agricultural | Loans Secured By Farmland | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	61	57
Agribusiness and Agricultural | Loans Secured By Farmland | Level 1 | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	0	0
Agribusiness and Agricultural | Loans Secured By Farmland | Level 2 | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	0	0
Agribusiness and Agricultural | Loans Secured By Farmland | Level 3 | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	61	57
Consumer 1-4 Family Mortgage Loans [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	411	1,061
Consumer 1-4 Family Mortgage Loans [Member] | Closed End First Mortgage Loans [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	411	474
Consumer 1-4 Family Mortgage Loans [Member] | Closed End First Mortgage Loans [Member] | Level 1 | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	0	0
Consumer 1-4 Family Mortgage Loans [Member] | Closed End First Mortgage Loans [Member] | Level 2 | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	0	0
Consumer 1-4 Family Mortgage Loans [Member] | Closed End First Mortgage Loans [Member] | Level 3 | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	$ 411	474
Consumer 1-4 Family Mortgage Loans [Member] | Open End and Junior Lien Loans | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans		587
Consumer 1-4 Family Mortgage Loans [Member] | Open End and Junior Lien Loans | Level 1 | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans		0
Consumer 1-4 Family Mortgage Loans [Member] | Open End and Junior Lien Loans | Level 2 | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans		0
Consumer 1-4 Family Mortgage Loans [Member] | Open End and Junior Lien Loans | Level 3 | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans		587
Consumer 1-4 Family Mortgage Loans [Member] | Other Consumer Loans [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans		11
Consumer 1-4 Family Mortgage Loans [Member] | Other Consumer Loans [Member] | Level 1 | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans		0
Consumer 1-4 Family Mortgage Loans [Member] | Other Consumer Loans [Member] | Level 2 | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans		0
Consumer 1-4 Family Mortgage Loans [Member] | Other Consumer Loans [Member] | Level 3 | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans		$ 11