FAIR VALUE MEASUREMENTS AND FAIR VALUES OF FINANCIAL INSTRUMENTS - Assets Measured at Fair Value (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Assets Measured at Fair Value
Total, fair value	$ 366,376	$ 349,332
Impaired loans with a valuation allowance	9,354	8,082
Valuation allowance	(1,124)	(925)
Impaired loans, net	9,354	8,082
Interest rate swap agreements
Assets Measured at Fair Value
Fair value derivative asset	3,933	6,566
Fair value of the derivative liability	3,933	6,566
Obligations of the U.S. Treasury
Assets Measured at Fair Value
Total, fair value	15,085	12,182
Obligations of U.S. Government agencies
Assets Measured at Fair Value
Total, fair value	24,992	26,344
Obligations Of States And Political Subdivisions Tax Exempt
Assets Measured at Fair Value
Total, fair value	125,118	122,401
Obligations Of States And Political Subdivisions Taxable
Assets Measured at Fair Value
Total, fair value	52,538	47,452
Residential Passthrough Securities
Assets Measured at Fair Value
Total, fair value	39,757	38,176
Residential Collateralized Mortgage Obligations
Assets Measured at Fair Value
Total, fair value	53,971	57,467
Commercial Mortgage Backed Securities
Assets Measured at Fair Value
Total, fair value	54,915	45,310
Recurring fair value measurements
Assets Measured at Fair Value
Total, fair value	366,376	349,332
Marketable equity security	982	1,000
Servicing rights	1,956	1,689
Total asset fair value measurements	373,247	358,587
Recurring fair value measurements \| Level 1
Assets Measured at Fair Value
Total, fair value	0	0
Marketable equity security	982	1,000
Servicing rights	0	0
Total asset fair value measurements	982	1,000
Recurring fair value measurements \| Level 2
Assets Measured at Fair Value
Total, fair value	366,376	349,332
Marketable equity security	0	0
Servicing rights	0	0
Total asset fair value measurements	370,309	355,898
Recurring fair value measurements \| Level 3
Assets Measured at Fair Value
Total, fair value	0	0
Marketable equity security	0	0
Servicing rights	1,956	1,689
Total asset fair value measurements	1,956	1,689
Recurring fair value measurements \| Interest rate swap agreements
Assets Measured at Fair Value
Fair value derivative asset	3,933	6,566
Fair value of the derivative liability	3,933	6,566
Recurring fair value measurements \| Interest rate swap agreements \| Level 1
Assets Measured at Fair Value
Fair value derivative asset	0	0
Fair value of the derivative liability	0	0
Recurring fair value measurements \| Interest rate swap agreements \| Level 2
Assets Measured at Fair Value
Fair value derivative asset	3,933	6,566
Fair value of the derivative liability	3,933	6,566
Recurring fair value measurements \| Interest rate swap agreements \| Level 3
Assets Measured at Fair Value
Fair value derivative asset	0	0
Fair value of the derivative liability	0	0
Recurring fair value measurements \| Obligations of the U.S. Treasury
Assets Measured at Fair Value
Total, fair value	15,085	12,182
Recurring fair value measurements \| Obligations of the U.S. Treasury \| Level 1
Assets Measured at Fair Value
Total, fair value	0	0
Recurring fair value measurements \| Obligations of the U.S. Treasury \| Level 2
Assets Measured at Fair Value
Total, fair value	15,085	12,182
Recurring fair value measurements \| Obligations of the U.S. Treasury \| Level 3
Assets Measured at Fair Value
Total, fair value	0	0
Recurring fair value measurements \| Obligations of U.S. Government agencies
Assets Measured at Fair Value
Total, fair value	24,992	26,344
Recurring fair value measurements \| Obligations of U.S. Government agencies \| Level 1
Assets Measured at Fair Value
Total, fair value	0	0
Recurring fair value measurements \| Obligations of U.S. Government agencies \| Level 2
Assets Measured at Fair Value
Total, fair value	24,992	26,344
Recurring fair value measurements \| Obligations of U.S. Government agencies \| Level 3
Assets Measured at Fair Value
Total, fair value	0	0
Recurring fair value measurements \| Obligations Of States And Political Subdivisions Tax Exempt
Assets Measured at Fair Value
Total, fair value	125,118	122,401
Recurring fair value measurements \| Obligations Of States And Political Subdivisions Tax Exempt \| Level 1
Assets Measured at Fair Value
Total, fair value	0	0
Recurring fair value measurements \| Obligations Of States And Political Subdivisions Tax Exempt \| Level 2
Assets Measured at Fair Value
Total, fair value	125,118	122,401
Recurring fair value measurements \| Obligations Of States And Political Subdivisions Tax Exempt \| Level 3
Assets Measured at Fair Value
Total, fair value	0	0
Recurring fair value measurements \| Obligations Of States And Political Subdivisions Taxable
Assets Measured at Fair Value
Total, fair value	52,538	47,452
Recurring fair value measurements \| Obligations Of States And Political Subdivisions Taxable \| Level 1
Assets Measured at Fair Value
Total, fair value	0	0
Recurring fair value measurements \| Obligations Of States And Political Subdivisions Taxable \| Level 2
Assets Measured at Fair Value
Total, fair value	52,538	47,452
Recurring fair value measurements \| Obligations Of States And Political Subdivisions Taxable \| Level 3
Assets Measured at Fair Value
Total, fair value	0	0
Recurring fair value measurements \| Residential Passthrough Securities
Assets Measured at Fair Value
Total, fair value	39,757	38,176
Recurring fair value measurements \| Residential Passthrough Securities \| Level 1
Assets Measured at Fair Value
Total, fair value	0	0
Recurring fair value measurements \| Residential Passthrough Securities \| Level 2
Assets Measured at Fair Value
Total, fair value	39,757	38,176
Recurring fair value measurements \| Residential Passthrough Securities \| Level 3
Assets Measured at Fair Value
Total, fair value	0	0
Recurring fair value measurements \| Residential Collateralized Mortgage Obligations
Assets Measured at Fair Value
Total, fair value	53,971	57,467
Recurring fair value measurements \| Residential Collateralized Mortgage Obligations \| Level 1
Assets Measured at Fair Value
Total, fair value	0	0
Recurring fair value measurements \| Residential Collateralized Mortgage Obligations \| Level 2
Assets Measured at Fair Value
Total, fair value	53,971	57,467
Recurring fair value measurements \| Residential Collateralized Mortgage Obligations \| Level 3
Assets Measured at Fair Value
Total, fair value	0	0
Recurring fair value measurements \| Commercial Mortgage Backed Securities
Assets Measured at Fair Value
Total, fair value	54,915	45,310
Recurring fair value measurements \| Commercial Mortgage Backed Securities \| Level 1
Assets Measured at Fair Value
Total, fair value	0	0
Recurring fair value measurements \| Commercial Mortgage Backed Securities \| Level 2
Assets Measured at Fair Value
Total, fair value	54,915	45,310
Recurring fair value measurements \| Commercial Mortgage Backed Securities \| Level 3
Assets Measured at Fair Value
Total, fair value	0	0
Nonrecurring fair value measurements
Assets Measured at Fair Value
Total asset fair value measurements	9,702	8,495
Impaired loans with a valuation allowance	9,354	8,082
Valuation allowance	(1,124)	(925)
Impaired loans, net	8,230	7,157
Foreclosed assets held for sale	1,472	1,338
Nonrecurring fair value measurements \| Level 1
Assets Measured at Fair Value
Total asset fair value measurements	0	0
Impaired loans with a valuation allowance	0	0
Valuation allowance	0	0
Impaired loans, net	0	0
Foreclosed assets held for sale	0	0
Nonrecurring fair value measurements \| Level 2
Assets Measured at Fair Value
Total asset fair value measurements	0	0
Impaired loans with a valuation allowance	0	0
Valuation allowance	0	0
Impaired loans, net	0	0
Foreclosed assets held for sale	0	0
Nonrecurring fair value measurements \| Level 3
Assets Measured at Fair Value
Total asset fair value measurements	9,702	8,495
Impaired loans with a valuation allowance	9,354	8,082
Valuation allowance	(1,124)	(925)
Impaired loans, net	8,230	7,157
Foreclosed assets held for sale	$ 1,472	$ 1,338

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Fair value of liability associated with financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset.

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Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

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Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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Amount of allowance for credit losses related to recorded investment.

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Fair value of an asset representing net future revenue from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements.

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