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v2.4.1.9

Loans - Impaired Loans by Class (Details) (USD $) In Thousands, unless otherwise specified | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2015 | Mar. 31, 2014 | Dec. 31, 2014
Schedule of Financing Receivables [Line Items] |  |  |
Recorded Investment | $ 34,833us-gaap_ImpairedFinancingReceivableRecordedInvestment | $ 40,587us-gaap_ImpairedFinancingReceivableRecordedInvestment | $ 35,862us-gaap_ImpairedFinancingReceivableRecordedInvestment
Unpaid Principal Balance | 38,244us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance | 44,547us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance | 39,026us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
Related Allowance | 1,436us-gaap_ImpairedFinancingReceivableRelatedAllowance | 2,786us-gaap_ImpairedFinancingReceivableRelatedAllowance | 1,803us-gaap_ImpairedFinancingReceivableRelatedAllowance
Average Recorded Investment | 35,121us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment | 41,597us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment | 38,404us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
Recognized Interest Income | 311us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod | 432us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod | 1,465us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod
With No Related Allowance |  |  |
Schedule of Financing Receivables [Line Items] |  |  |
Recorded Investment | 23,990us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember | 28,308us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember | 26,313us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember
Unpaid Principal Balance | 26,136us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember | 31,798us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember | 29,077us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember
Related Allowance | 0us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember | 0us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember | 0us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember
Average Recorded Investment | 25,806us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember | 29,787us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember | 26,926us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember
Recognized Interest Income | 213us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember | 312us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember | 1,078us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember
With an Allowance Recorded |  |  |
Schedule of Financing Receivables [Line Items] |  |  |
Recorded Investment | 10,843us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember | 12,279us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember | 9,549us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember
Unpaid Principal Balance | 12,108us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember | 12,749us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember | 9,949us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember
Related Allowance | 1,436us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember | 2,786us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember | 1,803us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember
Average Recorded Investment | 9,315us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember | 11,810us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember | 11,478us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember
Recognized Interest Income | 98us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember | 120us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember | 387us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember
Commercial real estate |  |  |
Schedule of Financing Receivables [Line Items] |  |  |
Recorded Investment | 12,705us-gaap_ImpairedFinancingReceivableRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember | 15,260us-gaap_ImpairedFinancingReceivableRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember | 13,304us-gaap_ImpairedFinancingReceivableRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember
Unpaid Principal Balance | 13,451us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember | 16,058us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember | 14,212us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember
Related Allowance | 248us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember | 1,019us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember | 346us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember
Average Recorded Investment | 12,895us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember | 15,268us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember | 14,120us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember
Recognized Interest Income | 120us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember | 128us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember | 550us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember
Commercial real estate | With No Related Allowance |  |  |
Schedule of Financing Receivables [Line Items] |  |  |
Recorded Investment | 9,062us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember | 11,428us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember | 11,687us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember
Unpaid Principal Balance | 9,496us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember | 12,066us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember | 12,423us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember
Related Allowance | 0us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember | 0us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember | 0us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember
Average Recorded Investment | 10,899us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember | 11,735us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember | 11,080us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember
Recognized Interest Income | 88us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember | 94us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember | 488us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember
Commercial real estate | With an Allowance Recorded |  |  |
Schedule of Financing Receivables [Line Items] |  |  |
Recorded Investment | 3,643us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember | 3,832us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember | 1,617us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember
Unpaid Principal Balance | 3,955us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember | 3,992us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember | 1,789us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember
Related Allowance | 248us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember | 1,019us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember | 346us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember
Average Recorded Investment | 1,996us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember | 3,533us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember | 3,040us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember
Recognized Interest Income | 32us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember | 34us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember | 62us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateMember
Commercial construction |  |  |
Schedule of Financing Receivables [Line Items] |  |  |
Recorded Investment | 1,380us-gaap_ImpairedFinancingReceivableRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember | 1,492us-gaap_ImpairedFinancingReceivableRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember | 1,380us-gaap_ImpairedFinancingReceivableRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember
Unpaid Principal Balance | 1,380us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember | 1,492us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember | 1,380us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember
Related Allowance | 396us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember | 276us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember | 413us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember
Average Recorded Investment | 1,372us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember | 1,354us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember | 1,309us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember
Recognized Interest Income | 13us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember | 16us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember | 56us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember
Commercial construction | With No Related Allowance |  |  |
Schedule of Financing Receivables [Line Items] |  |  |
Recorded Investment | 0us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember | 208us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember | 0us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember
Unpaid Principal Balance | 0us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember | 208us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember | 0us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember
Related Allowance | 0us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember | 0us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember | 0us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember
Average Recorded Investment | 0us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember | 69us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember | 30us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember
Recognized Interest Income | 0us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember | 0us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember | 0us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember
Commercial construction | With an Allowance Recorded |  |  |
Schedule of Financing Receivables [Line Items] |  |  |
Recorded Investment | 1,380us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember | 1,284us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember | 1,380us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember
Unpaid Principal Balance | 1,380us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember | 1,284us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember | 1,380us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember
Related Allowance | 396us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember | 276us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember | 413us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember
Average Recorded Investment | 1,372us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember | 1,284us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember | 1,279us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember
Recognized Interest Income | 13us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember | 16us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember | 56us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConstructionLoansMember
Commercial other |  |  |
Schedule of Financing Receivables [Line Items] |  |  |
Recorded Investment | 2,721us-gaap_ImpairedFinancingReceivableRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember | 5,258us-gaap_ImpairedFinancingReceivableRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember | 2,942us-gaap_ImpairedFinancingReceivableRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember
Unpaid Principal Balance | 3,526us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember | 7,007us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember | 3,745us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember
Related Allowance | 347us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember | 834us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember | 129us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember
Average Recorded Investment | 2,792us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember | 6,202us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember | 4,956us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember
Recognized Interest Income | 16us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember | 28us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember | 169us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember
Commercial other | With No Related Allowance |  |  |
Schedule of Financing Receivables [Line Items] |  |  |
Recorded Investment | 2,305us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember | 4,214us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember | 2,616us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember
Unpaid Principal Balance | 2,411us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember | 5,910us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember | 3,407us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember
Related Allowance | 0us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember | 0us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember | 0us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember
Average Recorded Investment | 2,465us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember | 5,148us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember | 3,853us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember
Recognized Interest Income | 16us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember | 24us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember | 156us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember
Commercial other | With an Allowance Recorded |  |  |
Schedule of Financing Receivables [Line Items] |  |  |
Recorded Investment | 416us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember | 1,044us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember | 326us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember
Unpaid Principal Balance | 1,115us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember | 1,097us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember | 338us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember
Related Allowance | 347us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember | 834us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember | 129us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember
Average Recorded Investment | 327us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember | 1,054us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember | 1,103us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember
Recognized Interest Income | 0us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember | 4us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember | 13us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_CommercialOtherMember
Residential term |  |  |
Schedule of Financing Receivables [Line Items] |  |  |
Recorded Investment | 16,348us-gaap_ImpairedFinancingReceivableRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember | 16,924us-gaap_ImpairedFinancingReceivableRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember | 16,123us-gaap_ImpairedFinancingReceivableRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember
Unpaid Principal Balance | 17,606us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember | 18,093us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember | 17,337us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember
Related Allowance | 421us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember | 574us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember | 519us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember
Average Recorded Investment | 16,369us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember | 17,142us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember | 16,243us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember
Recognized Interest Income | 153us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember | 253us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember | 641us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember
Residential term | With No Related Allowance |  |  |
Schedule of Financing Receivables [Line Items] |  |  |
Recorded Investment | 11,235us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember | 10,985us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember | 10,820us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember
Unpaid Principal Balance | 12,243us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember | 11,898us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember | 11,824us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember
Related Allowance | 0us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember | 0us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember | 0us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember
Average Recorded Investment | 11,136us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember | 11,325us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember | 10,505us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember
Recognized Interest Income | 100us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember | 188us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember | 402us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember
Residential term | With an Allowance Recorded |  |  |
Schedule of Financing Receivables [Line Items] |  |  |
Recorded Investment | 5,113us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember | 5,939us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember | 5,303us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember
Unpaid Principal Balance | 5,363us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember | 6,195us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember | 5,513us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember
Related Allowance | 421us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember | 574us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember | 519us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember
Average Recorded Investment | 5,233us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember | 5,817us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember | 5,738us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember
Recognized Interest Income | 53us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember | 65us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember | 239us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialTermMember
Residential construction |  |  |
Schedule of Financing Receivables [Line Items] |  |  |
Recorded Investment | 0us-gaap_ImpairedFinancingReceivableRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember | 0us-gaap_ImpairedFinancingReceivableRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember | 0us-gaap_ImpairedFinancingReceivableRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember
Unpaid Principal Balance | 0us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember | 0us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember | 0us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember
Related Allowance | 0us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember | 0us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember | 0us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember
Average Recorded Investment | 0us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember | 0us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember | 0us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember
Recognized Interest Income | 0us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember | 0us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember | 0us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember
Residential construction | With No Related Allowance |  |  |
Schedule of Financing Receivables [Line Items] |  |  |
Recorded Investment | 0us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember | 0us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember | 0us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember
Unpaid Principal Balance | 0us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember | 0us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember | 0us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember
Related Allowance | 0us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember | 0us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember | 0us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember
Average Recorded Investment | 0us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember | 0us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember | 0us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember
Recognized Interest Income | 0us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember | 0us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember | 0us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember
Residential construction | With an Allowance Recorded |  |  |
Schedule of Financing Receivables [Line Items] |  |  |
Recorded Investment | 0us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember | 0us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember | 0us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember
Unpaid Principal Balance | 0us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember | 0us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember | 0us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember
Related Allowance | 0us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember | 0us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember | 0us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember
Average Recorded Investment | 0us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember | 0us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember | 0us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember
Recognized Interest Income | 0us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember | 0us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember | 0us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = fnlc_ResidentialConstructionMember
Home equity line of credit |  |  |
Schedule of Financing Receivables [Line Items] |  |  |
Recorded Investment | 1,654us-gaap_ImpairedFinancingReceivableRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember | 1,653us-gaap_ImpairedFinancingReceivableRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember | 2,087us-gaap_ImpairedFinancingReceivableRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember
Unpaid Principal Balance | 2,253us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember | 1,897us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember | 2,324us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember
Related Allowance | 24us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember | 83us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember | 396us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember
Average Recorded Investment | 1,668us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember | 1,631us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember | 1,765us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember
Recognized Interest Income | 8us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember | 7us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember | 46us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember
Home equity line of credit | With No Related Allowance |  |  |
Schedule of Financing Receivables [Line Items] |  |  |
Recorded Investment | 1,363us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember | 1,473us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember | 1,164us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember
Unpaid Principal Balance | 1,958us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember | 1,716us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember | 1,395us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember
Related Allowance | 0us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember | 0us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember | 0us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember
Average Recorded Investment | 1,281us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember | 1,510us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember | 1,447us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember
Recognized Interest Income | 8us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember | 6us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember | 29us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember
Home equity line of credit | With an Allowance Recorded |  |  |
Schedule of Financing Receivables [Line Items] |  |  |
Recorded Investment | 291us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember | 180us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember | 923us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember
Unpaid Principal Balance | 295us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember | 181us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember | 929us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember
Related Allowance | 24us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember | 83us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember | 396us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember
Average Recorded Investment | 387us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember | 122us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember | 318us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember
Recognized Interest Income | 0us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember | 1us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember | 17us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_HomeEquityMember
Consumer |  |  |
Schedule of Financing Receivables [Line Items] |  |  |
Recorded Investment | 25us-gaap_ImpairedFinancingReceivableRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerLoanMember | 0us-gaap_ImpairedFinancingReceivableRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerLoanMember | 26us-gaap_ImpairedFinancingReceivableRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerLoanMember
Unpaid Principal Balance | 28us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerLoanMember | 0us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerLoanMember | 28us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerLoanMember
Related Allowance | 0us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerLoanMember | 0us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerLoanMember | 0us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerLoanMember
Average Recorded Investment | 25us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerLoanMember | 0us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerLoanMember | 11us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerLoanMember
Recognized Interest Income | 1us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerLoanMember | 0us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerLoanMember | 3us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerLoanMember
Consumer | With No Related Allowance |  |  |
Schedule of Financing Receivables [Line Items] |  |  |
Recorded Investment | 25us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerLoanMember | 0us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerLoanMember | 26us-gaap_ImpairedFinancingReceivableRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerLoanMember
Unpaid Principal Balance | 28us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerLoanMember | 0us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerLoanMember | 28us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerLoanMember
Related Allowance | 0us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerLoanMember | 0us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerLoanMember | 0us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithNoRelatedAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerLoanMember
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Consumer | With an Allowance Recorded |  |  |
Schedule of Financing Receivables [Line Items] |  |  |
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Unpaid Principal Balance | 0us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerLoanMember | 0us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerLoanMember | 0us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerLoanMember
Related Allowance | 0us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerLoanMember | 0us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerLoanMember | 0us-gaap_ImpairedFinancingReceivableRelatedAllowance / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerLoanMember
Average Recorded Investment | 0us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerLoanMember | 0us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerLoanMember | 0us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerLoanMember
Recognized Interest Income | $ 0us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerLoanMember | $ 0us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerLoanMember | $ 0us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod / fnlc_FinancingReceivableAllowanceAxis = fnlc_WithAllowanceRecordedMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerLoanMember

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