LOANS, ADDITIONAL INFORMATION (Details)	12 Months Ended
Dec. 31, 2020 USD ($) Loan	Dec. 31, 2019 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest income	$ 134,000	$ 75,000
Financing Receivable, Short Term Modifications, Dollar Amount	401,700,000
Financing Receivable, Short Term Modifications, Dollar Amount, End Of Period	$ 1,600,000
Financing Receivable, Short Term Modifications, Number, End Of Period \| Loan	3
Financing Receivable, CARES Act Section 4013 Modifications, Dollar Amount, End Of Period	$ 19,000,000.0
Financing Receivable, CARES Act Section 4013 Modifications, Number, End Of Period \| Loan	7
Financing Receivable, Short Term Modifications, Number \| Loan	600
Commercial & industrial \| Minimum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Adjustable interest rate periods of loan products	1 year
Commercial & industrial \| Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Adjustable interest rate periods of loan products	10 years
Commercial, secured by real estate \| Minimum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortization period of loan products	5 years
Balloon payment terms of loan products	1 year
Adjustable interest rate periods of loan products	1 year
Loan to appraised value ratio of loan products	75.00%
Commercial, secured by real estate \| Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortization period of loan products	25 years
Balloon payment terms of loan products	10 years
Adjustable interest rate periods of loan products	10 years
Loan to appraised value ratio of loan products	85.00%
Residential real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Home equity lines of credit draw period of residential real estate loans	5 years
Residential real estate \| Minimum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortization period of loan products	5 years
Adjustable interest rate periods of loan products	1 year
Loan to appraised value ratio of loan products	80.00%
Residential real estate \| Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortization period of loan products	30 years
Adjustable interest rate periods of loan products	10 years
Consumer \| Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortization period of loan products	72 months
Paycheck Protection Program Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortization period of loan products	2 years
Financing Receivable, Interest Rate	1.00%
Paycheck Protection Program Loans \| Minimum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Processing Fee, Percent Of Loan Amount	1.00%
Paycheck Protection Program Loans \| Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Processing Fee, Percent Of Loan Amount	5.00%

Financing Receivable, Amortization Period

No definition available.

Name:	lcnb_FinancingReceivableAmortizationPeriod
Namespace Prefix:	lcnb_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Financing Receivable, CARES Act Section 4013 Modifications, Dollar Amount, End Of Period

+ References

No definition available.

+ Details

Name:	lcnb_FinancingReceivableCARESActSection4013ModificationsDollarAmountEndOfPeriod
Namespace Prefix:	lcnb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Financing Receivable, CARES Act Section 4013 Modifications, Number, End Of Period

+ References

No definition available.

+ Details

Name:	lcnb_FinancingReceivableCARESActSection4013ModificationsNumberEndOfPeriod
Namespace Prefix:	lcnb_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Financing Receivable, Interest Rate

+ References

No definition available.

+ Details

Name:	lcnb_FinancingReceivableInterestRate
Namespace Prefix:	lcnb_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Financing Receivable, Line of Credit Draw Period

+ References

No definition available.

+ Details

Name:	lcnb_FinancingReceivableLineOfCreditDrawPeriod
Namespace Prefix:	lcnb_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Financing Receivable, Periodic Payment Terms, Balloon Payment Period

+ References

No definition available.

+ Details

Name:	lcnb_FinancingReceivablePeriodicPaymentTermsBalloonPaymentPeriod
Namespace Prefix:	lcnb_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Financing Receivable, Processing Fee, Percent Of Loan Amount

+ References

No definition available.

+ Details

Name:	lcnb_FinancingReceivableProcessingFeePercentOfLoanAmount
Namespace Prefix:	lcnb_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Financing Receivable, Short Term Modifications, Dollar Amount

+ References

No definition available.

+ Details

Name:	lcnb_FinancingReceivableShortTermModificationsDollarAmount
Namespace Prefix:	lcnb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Financing Receivable, Short Term Modifications, Dollar Amount, End Of Period

+ References

No definition available.

+ Details

Name:	lcnb_FinancingReceivableShortTermModificationsDollarAmountEndOfPeriod
Namespace Prefix:	lcnb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Financing Receivable, Short Term Modifications, Number

+ References

No definition available.

+ Details

Name:	lcnb_FinancingReceivableShortTermModificationsNumber
Namespace Prefix:	lcnb_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Financing Receivable, Short Term Modifications, Number, End Of Period

+ References

No definition available.

+ Details

Name:	lcnb_FinancingReceivableShortTermModificationsNumberEndOfPeriod
Namespace Prefix:	lcnb_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Financing Receivable, Variable Rates of Interest, Adjustment Period

+ References

No definition available.

+ Details

Name:	lcnb_FinancingReceivableVariableRatesOfInterestAdjustmentPeriod
Namespace Prefix:	lcnb_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Loan and Lease Receivable, Ratio of Loan to Appraised Value

+ References

No definition available.

+ Details

Name:	lcnb_LoanAndLeaseReceivableRatioOfLoanToAppraisedValue
Namespace Prefix:	lcnb_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_AccountsNotesAndLoansReceivableLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Reflects the amount of additional interest income that would have been recorded if impaired or nonperforming loans were instead current, in compliance with their original terms, and outstanding throughout the reporting period or since origination (if held for part of the period).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 40
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=121585226&loc=d3e18794-111554

+ Details

Name:	us-gaap_LoansAndLeasesReceivableImpairedInterestLostOnNonaccrualLoans
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialRealEstatePortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ResidentialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=lcnb_PaycheckProtectionProgramLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: