LOANS, Non-accrual and Past Due Loans (Details)	Mar. 31, 2021 USD ($) Loan	Dec. 31, 2020 USD ($) Loan	Mar. 31, 2020 USD ($)
Non-accrual and Past Due Loans [Abstract]
Current & accruing	$ 944,796,000	$ 878,003,000
Nonaccrual	17,052,000	15,211,000
Total	962,442,000	893,214,000	$ 770,565,000
Commitments to lend additional funds to borrower whose loan was on non-accrual status	0
30-59 Days Past Due [Member]
Non-accrual and Past Due Loans [Abstract]
Past due & accruing	594,000	0
60-89 Days Past Due [Member]
Non-accrual and Past Due Loans [Abstract]
Past due & accruing	0	0
90 Days or More Past Due [Member]
Non-accrual and Past Due Loans [Abstract]
Past due & accruing	0	0
Commercial [Member]
Non-accrual and Past Due Loans [Abstract]
Current & accruing	292,494,000	255,563,000
Nonaccrual	284,000	363,000
Total	$ 293,148,000	$ 255,926,000	113,346,000
Number of nonaccrual loans | Loan	3	4
Commercial [Member] | 30-59 Days Past Due [Member]
Non-accrual and Past Due Loans [Abstract]
Past due & accruing	$ 370,000	$ 0
Commercial [Member] | 60-89 Days Past Due [Member]
Non-accrual and Past Due Loans [Abstract]
Past due & accruing	0	0
Commercial [Member] | 90 Days or More Past Due [Member]
Non-accrual and Past Due Loans [Abstract]
Past due & accruing	0	0
Commercial Real Estate [Member]
Non-accrual and Past Due Loans [Abstract]
Current & accruing	490,045,000	449,178,000
Nonaccrual	6,803,000	4,875,000
Total	$ 496,848,000	$ 454,053,000	452,611,000
Number of nonaccrual loans | Loan	4	3
Commercial Real Estate [Member] | 30-59 Days Past Due [Member]
Non-accrual and Past Due Loans [Abstract]
Past due & accruing	$ 0	$ 0
Commercial Real Estate [Member] | 60-89 Days Past Due [Member]
Non-accrual and Past Due Loans [Abstract]
Past due & accruing	0	0
Commercial Real Estate [Member] | 90 Days or More Past Due [Member]
Non-accrual and Past Due Loans [Abstract]
Past due & accruing	0	0
Agriculture [Member]
Non-accrual and Past Due Loans [Abstract]
Current & accruing	70,825,000	85,918,000
Nonaccrual	9,130,000	9,130,000
Total	$ 79,955,000	$ 95,048,000	94,303,000
Number of nonaccrual loans | Loan	3	3
Agriculture [Member] | 30-59 Days Past Due [Member]
Non-accrual and Past Due Loans [Abstract]
Past due & accruing	$ 0	$ 0
Agriculture [Member] | 60-89 Days Past Due [Member]
Non-accrual and Past Due Loans [Abstract]
Past due & accruing	0	0
Agriculture [Member] | 90 Days or More Past Due [Member]
Non-accrual and Past Due Loans [Abstract]
Past due & accruing	0	0
Residential Mortgage [Member]
Non-accrual and Past Due Loans [Abstract]
Current & accruing	70,740,000	64,344,000
Nonaccrual	148,000	153,000
Total	$ 71,112,000	$ 64,497,000	66,184,000
Number of nonaccrual loans | Loan	1	1
Residential Mortgage [Member] | 30-59 Days Past Due [Member]
Non-accrual and Past Due Loans [Abstract]
Past due & accruing	$ 224,000	$ 0
Residential Mortgage [Member] | 60-89 Days Past Due [Member]
Non-accrual and Past Due Loans [Abstract]
Past due & accruing	0	0
Residential Mortgage [Member] | 90 Days or More Past Due [Member]
Non-accrual and Past Due Loans [Abstract]
Past due & accruing	0	0
Residential Construction [Member]
Non-accrual and Past Due Loans [Abstract]
Current & accruing	2,662,000	4,223,000
Nonaccrual	0	0
Total	2,662,000	4,223,000	19,086,000
Residential Construction [Member] | 30-59 Days Past Due [Member]
Non-accrual and Past Due Loans [Abstract]
Past due & accruing	0	0
Residential Construction [Member] | 60-89 Days Past Due [Member]
Non-accrual and Past Due Loans [Abstract]
Past due & accruing	0	0
Residential Construction [Member] | 90 Days or More Past Due [Member]
Non-accrual and Past Due Loans [Abstract]
Past due & accruing	0	0
Consumer [Member]
Non-accrual and Past Due Loans [Abstract]
Current & accruing	18,030,000	18,777,000
Nonaccrual	687,000	690,000
Total	$ 18,717,000	$ 19,467,000	$ 25,035,000
Number of nonaccrual loans | Loan	4	5
Consumer [Member] | 30-59 Days Past Due [Member]
Non-accrual and Past Due Loans [Abstract]
Past due & accruing	$ 0	$ 0
Consumer [Member] | 60-89 Days Past Due [Member]
Non-accrual and Past Due Loans [Abstract]
Past due & accruing	0	0
Consumer [Member] | 90 Days or More Past Due [Member]
Non-accrual and Past Due Loans [Abstract]
Past due & accruing	$ 0	$ 0