Increase (decrease) in allowance for loan loss.

No definition available.

Name:	lkfn_IncreaseDecreaseInAllowanceForLoanLoss
Namespace Prefix:	lkfn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The minimum loan amount required for credit quality analysis.

+ References

No definition available.

+ Details

Name:	lkfn_LoanAmountOfCreditQualityAnalysis
Namespace Prefix:	lkfn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount included in the allowance for loan loss for specific reserves on loans whose terms have been modified in trouble debt restructuring.

+ References

No definition available.

+ Details

Name:	lkfn_LoansModifiedInTroubledDebtRestructuredLoans
Namespace Prefix:	lkfn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- References

No definition available.

+ Details

Name:	lkfn_TroubledDebtRestructuringAbstract
Namespace Prefix:	lkfn_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of the outstanding recorded investment related to financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 40
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=82895541&loc=d3e18845-111554

+ Details

Name:	us-gaap_FinancingReceivableModificationsRecordedInvestment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of investment related to financing receivables modified by troubled debt restructurings within the previous 12 months, for which there was a payment default.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 34
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953682-111524

+ Details

Name:	us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=lkfn_TotalCommercialAndIndustrialLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	lkfn_PortfolioSegmentAxis=lkfn_NonWorkingCapitalLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	lkfn_PortfolioSegmentAxis=lkfn_WorkingCapitalLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	lkfn_PortfolioSegmentAxis=lkfn_TwoCommercialCreditsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

ALLOWANCE FOR LOAN LOSSES AND CREDIT QUALITY (Additional Information) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Troubled Debt Restructuring [Abstract]
Loans Modified In Troubled Debt Restructured Loans			$ 2,300,000
Loan amount of credit quality analysis	$ 150,000
Commercial and industrial loans:
Troubled Debt Restructuring [Abstract]
Increase (decrease) in allowance for loan loss		$ 34,000
Financing Receivable, Modifications, Recorded Investment	341,000
Commercial and industrial loans: \| Non-working capital loans
Troubled Debt Restructuring [Abstract]
Financing Receivable, Modifications, Recorded Investment	551,000
Commercial and industrial loans: \| Working Capital Loan [Member]
Troubled Debt Restructuring [Abstract]
Financing Receivable, Modifications, Recorded Investment		690,000
Commercial Real Estate and Multi-Family Residential Loans [Member]
Troubled Debt Restructuring [Abstract]
Increase (decrease) in allowance for loan loss	227,000	49,000
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 1,600,000
Commercial Real Estate and Multi-Family Residential Loans [Member] \| Two Commercial Credits [Member]
Troubled Debt Restructuring [Abstract]
Financing Receivable, Modifications, Recorded Investment		$ 500,000