LOANS AND RELATED ALLOWANCE FOR LOAN LOSSES, Past Due (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Recorded investment of past due [Abstract]
Total past due	$ 11,046,000	$ 9,730,000
Current	1,389,360,000	1,104,557,000
PCI	4,875,000	1,282,000
Total loan receivables	1,405,281,000	1,115,569,000
90 Days past due and accruing	525,000	487,000
Financing receivables on nonaccrual status [Abstract]
Total past due and non-accrual	6,401,000	6,532,000
Current and non-accrual	4,331,000	5,004,000
PCI Loans considered non accrual	0	0
Financing receivable nonaccrual status	10,732,000	11,536,000
Foregone interest income	756,000	647,000	$ 961,000
Financing receivables on accrual status [Abstract]
Total past due and still accruing	4,645,000	3,198,000
Current and still accruing	1,385,029,000	1,099,553,000
PCI Loans still accruing	4,875,000	1,282,000
Total financing receivables and still accruing	$ 1,394,549,000	1,104,033,000
Minimum [Member]
Financing receivables on nonaccrual status [Abstract]
Period of past due after which loans considered as non accrual	90 days
30 to 59 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	$ 6,256,000	2,142,000
Financing receivables on nonaccrual status [Abstract]
Total past due and non-accrual	3,032,000	90,000
Financing receivables on accrual status [Abstract]
Total past due and still accruing	3,224,000	2,052,000
60 to 89 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	924,000	754,000
Financing receivables on nonaccrual status [Abstract]
Total past due and non-accrual	28,000	95,000
Financing receivables on accrual status [Abstract]
Total past due and still accruing	896,000	659,000
90 Days Or Greater [Member]
Recorded investment of past due [Abstract]
Total past due	3,866,000	6,834,000
Financing receivables on nonaccrual status [Abstract]
Total past due and non-accrual	3,341,000	6,347,000
Financing receivables on accrual status [Abstract]
Total past due and still accruing	525,000	487,000
Real Estate Loans [Member] | Mortgages [Member]
Recorded investment of past due [Abstract]
Total past due	1,796,000	957,000
Current	145,086,000	156,098,000
PCI	20,000	23,000
Total loan receivables	146,902,000	157,078,000
90 Days past due and accruing	252,000	1,000
Financing receivables on nonaccrual status [Abstract]
Financing receivable nonaccrual status	787,000	903,000
Real Estate Loans [Member] | Mortgages [Member] | 30 to 59 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	864,000	581,000
Real Estate Loans [Member] | Mortgages [Member] | 60 to 89 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	414,000	57,000
Real Estate Loans [Member] | Mortgages [Member] | 90 Days Or Greater [Member]
Recorded investment of past due [Abstract]
Total past due	518,000	319,000
Real Estate Loans [Member] | Home Equity [Member]
Recorded investment of past due [Abstract]
Total past due	248,000	401,000
Current	54,761,000	59,609,000
PCI	0	0
Total loan receivables	55,009,000	60,010,000
90 Days past due and accruing	23,000	1,000
Financing receivables on nonaccrual status [Abstract]
Financing receivable nonaccrual status	25,000	59,000
Real Estate Loans [Member] | Home Equity [Member] | 30 to 59 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	152,000	334,000
Real Estate Loans [Member] | Home Equity [Member] | 60 to 89 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	62,000	11,000
Real Estate Loans [Member] | Home Equity [Member] | 90 Days Or Greater [Member]
Recorded investment of past due [Abstract]
Total past due	34,000	56,000
Real Estate Loans [Member] | Commercial [Member]
Recorded investment of past due [Abstract]
Total past due	3,097,000	5,043,000
Current	590,221,000	335,770,000
PCI	2,937,000	1,210,000
Total loan receivables	596,255,000	342,023,000
90 Days past due and accruing	70,000	0
Financing receivables on nonaccrual status [Abstract]
Financing receivable nonaccrual status	4,529,000	5,080,000
Real Estate Loans [Member] | Commercial [Member] | 30 to 59 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	836,000	750,000
Real Estate Loans [Member] | Commercial [Member] | 60 to 89 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	439,000	573,000
Real Estate Loans [Member] | Commercial [Member] | 90 Days Or Greater [Member]
Recorded investment of past due [Abstract]
Total past due	1,822,000	3,720,000
Real Estate Loans [Member] | Agricultural [Member]
Recorded investment of past due [Abstract]
Total past due	3,612,000	903,000
Current	309,860,000	310,561,000
PCI	1,686,000	0
Total loan receivables	315,158,000	311,464,000
90 Days past due and accruing	150,000	299,000
Financing receivables on nonaccrual status [Abstract]
Financing receivable nonaccrual status	3,133,000	2,578,000
Real Estate Loans [Member] | Agricultural [Member] | 30 to 59 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	2,283,000	118,000
Real Estate Loans [Member] | Agricultural [Member] | 60 to 89 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	0	0
Real Estate Loans [Member] | Agricultural [Member] | 90 Days Or Greater [Member]
Recorded investment of past due [Abstract]
Total past due	1,329,000	785,000
Real Estate Loans [Member] | Construction [Member]
Recorded investment of past due [Abstract]
Total past due	0	0
Current	35,404,000	15,519,000
PCI	0	0
Total loan receivables	35,404,000	15,519,000
90 Days past due and accruing	0	0
Real Estate Loans [Member] | Construction [Member] | 30 to 59 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	0	0
Real Estate Loans [Member] | Construction [Member] | 60 to 89 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	0	0
Real Estate Loans [Member] | Construction [Member] | 90 Days Or Greater [Member]
Recorded investment of past due [Abstract]
Total past due	0	0
Consumer [Member]
Recorded investment of past due [Abstract]
Total past due	186,000	131,000
Current	30,091,000	9,816,000
PCI	0	0
Total loan receivables	30,277,000	9,947,000
90 Days past due and accruing	30,000	2,000
Financing receivables on nonaccrual status [Abstract]
Financing receivable nonaccrual status	0	6,000
Consumer [Member] | 30 to 59 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	147,000	113,000
Consumer [Member] | 60 to 89 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	9,000	10,000
Consumer [Member] | 90 Days Or Greater [Member]
Recorded investment of past due [Abstract]
Total past due	30,000	8,000
Other Commercial Loans [Member]
Recorded investment of past due [Abstract]
Total past due	1,063,000	2,234,000
Current	112,874,000	67,687,000
PCI	232,000	49,000
Total loan receivables	114,169,000	69,970,000
90 Days past due and accruing	0	184,000
Financing receivables on nonaccrual status [Abstract]
Financing receivable nonaccrual status	1,284,000	1,837,000
Other Commercial Loans [Member] | 30 to 59 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	930,000	217,000
Other Commercial Loans [Member] | 60 to 89 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	0	71,000
Other Commercial Loans [Member] | 90 Days Or Greater [Member]
Recorded investment of past due [Abstract]
Total past due	133,000	1,946,000
Other Agricultural Loans [Member]
Recorded investment of past due [Abstract]
Total past due	1,044,000	61,000
Current	47,735,000	55,051,000
PCI	0	0
Total loan receivables	48,779,000	55,112,000
90 Days past due and accruing	0	0
Financing receivables on nonaccrual status [Abstract]
Financing receivable nonaccrual status	974,000	1,073,000
Other Agricultural Loans [Member] | 30 to 59 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	1,044,000	29,000
Other Agricultural Loans [Member] | 60 to 89 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	0	32,000
Other Agricultural Loans [Member] | 90 Days Or Greater [Member]
Recorded investment of past due [Abstract]
Total past due	0	0
State and Political Subdivision Loans [Member]
Recorded investment of past due [Abstract]
Total past due	0	0
Current	63,328,000	94,446,000
PCI	0	0
Total loan receivables	63,328,000	94,446,000
90 Days past due and accruing	0	0
State and Political Subdivision Loans [Member] | 30 to 59 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	0	0
State and Political Subdivision Loans [Member] | 60 to 89 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	0	0
State and Political Subdivision Loans [Member] | 90 Days Or Greater [Member]
Recorded investment of past due [Abstract]
Total past due	$ 0	$ 0