XML 48 R45.htm IDEA: XBRL DOCUMENT 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
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Schedule of Financing Receivables [Line Items]      
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Schedule of Financing Receivables [Line Items]      
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Schedule of Financing Receivables [Line Items]      
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Home equity line of credit      
Schedule of Financing Receivables [Line Items]      
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/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
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/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
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Home equity line of credit | With No Related Allowance      
Schedule of Financing Receivables [Line Items]      
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/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
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Related Allowance 0us-gaap_ImpairedFinancingReceivableRelatedAllowance
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/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
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Home equity line of credit | With an Allowance Recorded      
Schedule of Financing Receivables [Line Items]      
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/ fnlc_FinancingReceivableAllowanceAxis
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/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
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/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
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Consumer      
Schedule of Financing Receivables [Line Items]      
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/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
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/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
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/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
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/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
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/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
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