$FNLC
First Bancorp, Inc /ME/ Stock $fnlc

$fnlc Overview Financials Valuation SEC Filings Company Website

2024 Q1 Form 10-K Financial Statement

#000076520724000010 Filed on March 08, 2024

Income Statement

Concept	2024 Q1	2023 Q4	2023
Revenue	$34.99M	$34.82M	$128.2M
YoY Change	21.01%	28.59%	37.77%
Cost Of Revenue
YoY Change
Gross Profit
YoY Change
Gross Profit Margin
Selling, General & Admin
YoY Change
% of Gross Profit
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$544.0K	$547.0K	$2.107M
YoY Change	9.9%	11.86%	6.2%
% of Gross Profit
Operating Expenses
YoY Change
Operating Profit
YoY Change
Interest Expense	$20.11M	$18.97M	$62.97M
YoY Change	75.78%	149.72%	273.27%
% of Operating Profit
Other Income/Expense, Net
YoY Change
Pretax Income	$7.272M	$8.091M	$35.70M
YoY Change	-24.6%	-27.56%	-24.65%
Income Tax	$1.251M	$1.411M	$6.184M
% Of Pretax Income	17.2%	17.44%	17.32%
Net Earnings	$6.021M	$6.680M	$29.52M
YoY Change	-24.46%	-27.37%	-24.29%
Net Earnings / Revenue	17.21%	19.18%	23.03%
Basic Earnings Per Share	$0.55	$0.60	$2.68
Diluted Earnings Per Share	$0.54	$0.60	$2.66
COMMON SHARES
Basic Shares Outstanding	11.13M shares	11.09M shares	11.00M shares
Diluted Shares Outstanding	11.12M shares		11.08M shares

Balance Sheet

Concept	2024 Q1	2023 Q4	2023
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents	$23.88M	$31.94M
Short-Term Investments
Other Short-Term Assets
YoY Change
Inventory
Prepaid Expenses
Receivables
Other Receivables
Total Short-Term Assets
YoY Change
LONG-TERM ASSETS
Property, Plant & Equipment	$28.44M	$28.68M	$28.68M
YoY Change	0.53%	1.44%	1.44%
Goodwill	$30.65M	$30.65M
YoY Change	0.0%	0.0%
Intangibles
YoY Change
Long-Term Investments
YoY Change
Other Assets			$11.03M
YoY Change			0.43%
Total Long-Term Assets
YoY Change
TOTAL ASSETS
Total Short-Term Assets
Total Long-Term Assets
Total Assets	$2.978B	$2.947B	$2.947B
YoY Change	5.92%	7.58%	7.58%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable
YoY Change
Accrued Expenses			$652.0K
YoY Change			-11.53%
Deferred Revenue
YoY Change
Short-Term Debt	$84.78M	$69.65M	$49.58M
YoY Change	1.17%	-32.64%	-23.03%
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities		$49.58M	$50.23M
YoY Change		-23.03%	6715.2%
LONG-TERM LIABILITIES
Long-Term Debt	$0.00	$0.00	$0.00
YoY Change
Other Long-Term Liabilities	$31.78M	$34.31M	$34.31M
YoY Change	-3.04%	22.98%	22.98%
Total Long-Term Liabilities	$31.78M	$34.31M	$34.31M
YoY Change	-3.04%	22.98%	22.98%
TOTAL LIABILITIES
Total Short-Term Liabilities		$49.58M	$50.23M
Total Long-Term Liabilities	$31.78M	$34.31M	$34.31M
Total Liabilities	$2.736B	$2.704B	$2.704B
YoY Change	5.89%	7.7%	7.7%
SHAREHOLDERS EQUITY
Retained Earnings	$213.8M	$211.9M
YoY Change	5.84%	3.71%
Common Stock	$111.0K	$111.0K
YoY Change	0.0%	0.91%
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity	$242.6M	$243.1M	$243.1M
YoY Change
Total Liabilities & Shareholders Equity	$2.978B	$2.947B	$2.947B
YoY Change	5.92%	7.58%	7.58%

Cashflow Statement

Concept	2024 Q1	2023 Q4	2023
OPERATING ACTIVITIES
Net Income	$6.021M	$6.680M	$29.52M
YoY Change	-24.46%	-27.37%	-24.29%
Depreciation, Depletion And Amortization	$544.0K	$547.0K	$2.107M
YoY Change	9.9%	11.86%	6.2%
Cash From Operating Activities	-$1.497M	$10.73M	$36.92M
YoY Change	-129.66%	22.2%	-10.42%
INVESTING ACTIVITIES
Capital Expenditures	$326.0K	$385.0K	$2.635M
YoY Change	-38.02%	61.09%	87.68%
Acquisitions
YoY Change
Other Investing Activities	-$36.78M	$8.997M	-$197.2M
YoY Change	-42.72%	-340.5%	-19.91%
Cash From Investing Activities	-$37.11M	$8.612M	-$199.8M
YoY Change	-42.68%	-316.38%	-19.3%
FINANCING ACTIVITIES
Cash Dividend Paid	$3.907M		$15.42M
YoY Change	3.55%		4.32%
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	$30.54M	-17.30M	$172.1M
YoY Change	-52.6%	82.46%	-17.44%
NET CHANGE
Cash From Operating Activities	-$1.497M	10.73M	$36.92M
Cash From Investing Activities	-$37.11M	8.612M	-$199.8M
Cash From Financing Activities	$30.54M	-17.30M	$172.1M
Net Change In Cash	-$8.067M	2.044M	$9.214M
YoY Change	-270.55%	-143.68%	340.02%
FREE CASH FLOW
Cash From Operating Activities	-$1.497M	$10.73M	$36.92M
Capital Expenditures	$326.0K	$385.0K	$2.635M
Free Cash Flow	-$1.823M	$10.34M	$34.28M
YoY Change	-140.32%	21.11%	-13.88%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
CY2023Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	338570000	usd
CY2023	fnlc	Availableforsale Securities Transferredto Heldtomaturity Securities Unrealized Gain Loss AvailableforsaleSecuritiesTransferredtoHeldtomaturitySecuritiesUnrealizedGainLoss	8000	usd
CY2023	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	34455000	usd
CY2023	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.39
CY2023	us-gaap	Dividends Cash DividendsCash	15409000	usd
CY2023	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	820000	usd
CY2023	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	250000	usd
CY2023	us-gaap	Net Income Loss NetIncomeLoss	29518000	usd
CY2022	us-gaap	Accounting Standards Update Extensible List AccountingStandardsUpdateExtensibleList	http://fasb.org/us-gaap/2023#AccountingStandardsUpdate201613Member
CY2022Q4	us-gaap	Operating Lease Right Of Use Asset Statement Of Financial Position Extensible List OperatingLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList	http://www.thefirst.com/20231231#PropertyPlantAndEquipmentAndOperatingLeaseRightOfUseAssetNetOfAccumulatedDepreciationAndAmortization
CY2023Q4	us-gaap	Operating Lease Right Of Use Asset Statement Of Financial Position Extensible List OperatingLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList	http://www.thefirst.com/20231231#PropertyPlantAndEquipmentAndOperatingLeaseRightOfUseAssetNetOfAccumulatedDepreciationAndAmortization
CY2023Q4	us-gaap	Operating Lease Liability Statement Of Financial Position Extensible List OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2023#OtherLiabilities
CY2022Q4	us-gaap	Operating Lease Liability Statement Of Financial Position Extensible List OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2023#OtherLiabilities
CY2023Q4	us-gaap	Derivative Asset Statement Of Financial Position Extensible Enumeration DerivativeAssetStatementOfFinancialPositionExtensibleEnumeration	http://fasb.org/us-gaap/2023#OtherAssets
CY2023Q4	us-gaap	Derivative Liability Statement Of Financial Position Extensible Enumeration DerivativeLiabilityStatementOfFinancialPositionExtensibleEnumeration	http://fasb.org/us-gaap/2023#OtherLiabilities
CY2023Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	31942000	usd
CY2022Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	22728000	usd
CY2023Q4	us-gaap	Interest Bearing Deposits In Banks InterestBearingDepositsInBanks	3488000	usd
CY2022Q4	us-gaap	Interest Bearing Deposits In Banks InterestBearingDepositsInBanks	3693000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest DebtSecuritiesAvailableForSaleExcludingAccruedInterest	282053000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest DebtSecuritiesAvailableForSaleExcludingAccruedInterest	284509000	usd
CY2023Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	434000	usd
CY2022Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	339011000	usd
CY2022Q4	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest After Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss	393896000	usd
CY2023Q4	us-gaap	Interest Receivable InterestReceivable	11894000	usd
CY2023Q4	fnlc	Property Plant And Equipment And Operating Lease Right Of Use Asset Net Of Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndOperatingLeaseRightOfUseAssetNetOfAccumulatedDepreciationAndAmortization	28684000	usd
CY2022Q4	fnlc	Property Plant And Equipment And Operating Lease Right Of Use Asset Net Of Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndOperatingLeaseRightOfUseAssetNetOfAccumulatedDepreciationAndAmortization	28277000	usd
CY2023Q4	us-gaap	Goodwill Goodwill	30646000	usd
CY2022Q4	us-gaap	Goodwill Goodwill	30646000	usd
CY2023Q4	us-gaap	Other Assets OtherAssets	63947000	usd
CY2022Q4	us-gaap	Other Assets OtherAssets	63491000	usd
CY2023Q4	us-gaap	Assets Assets	2946698000	usd
CY2022Q4	us-gaap	Assets Assets	2739178000	usd
CY2023Q4	us-gaap	Demand Deposit Accounts DemandDepositAccounts	289104000	usd
CY2022Q4	us-gaap	Demand Deposit Accounts DemandDepositAccounts	318626000	usd
CY2023Q4	us-gaap	Deposits Negotiable Order Of Withdrawal Now DepositsNegotiableOrderOfWithdrawalNOW	634543000	usd
CY2022Q4	us-gaap	Deposits Negotiable Order Of Withdrawal Now DepositsNegotiableOrderOfWithdrawalNOW	630416000	usd
CY2023Q4	us-gaap	Deposits Money Market Deposits DepositsMoneyMarketDeposits	305931000	usd
CY2022Q4	us-gaap	Deposits Money Market Deposits DepositsMoneyMarketDeposits	192632000	usd
CY2023Q4	us-gaap	Deposits Savings Deposits DepositsSavingsDeposits	299837000	usd
CY2022Q4	us-gaap	Deposits Savings Deposits DepositsSavingsDeposits	369532000	usd
CY2023Q4	us-gaap	Time Deposits TimeDeposits	1070247000	usd
CY2022Q4	us-gaap	Time Deposits TimeDeposits	867671000	usd
CY2023Q4	us-gaap	Deposits Deposits	2599662000	usd
CY2022Q4	us-gaap	Deposits Deposits	2378877000	usd
CY2023Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	69652000	usd
CY2022Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	103399000	usd
CY2023Q4	us-gaap	Long Term Debt LongTermDebt	0	usd
CY2022Q4	us-gaap	Long Term Debt LongTermDebt	84000	usd
CY2023Q4	us-gaap	Other Liabilities OtherLiabilities	34305000	usd
CY2022Q4	us-gaap	Other Liabilities OtherLiabilities	27895000	usd
CY2023Q4	us-gaap	Liabilities Liabilities	2703619000	usd
CY2022Q4	us-gaap	Liabilities Liabilities	2510255000	usd
CY2023Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		usd
CY2022Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		usd
CY2023Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.01
CY2022Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.01
CY2023Q4	us-gaap	Common Stock Value CommonStockValue	111000	usd
CY2022Q4	us-gaap	Common Stock Value CommonStockValue	110000	usd
CY2023Q4	us-gaap	Additional Paid In Capital AdditionalPaidInCapital	70071000	usd
CY2022Q4	us-gaap	Additional Paid In Capital AdditionalPaidInCapital	68435000	usd
CY2023Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	211925000	usd
CY2022Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	204343000	usd
CY2023Q4	us-gaap	Accumulated Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	-39575000	usd
CY2022Q4	us-gaap	Accumulated Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	-44718000	usd
CY2023Q4	fnlc	Other Comprehensive Income Loss Accumulated Unrealized Gain Losson Transferof Availableforsale Securitiesto Heldtomaturity OtherComprehensiveIncomeLossAccumulatedUnrealizedGainLossonTransferofAvailableforsaleSecuritiestoHeldtomaturity	-56000	usd
CY2022Q4	fnlc	Other Comprehensive Income Loss Accumulated Unrealized Gain Losson Transferof Availableforsale Securitiesto Heldtomaturity OtherComprehensiveIncomeLossAccumulatedUnrealizedGainLossonTransferofAvailableforsaleSecuritiestoHeldtomaturity	-64000	usd
CY2023Q4	us-gaap	Aoci Loss Cash Flow Hedge Cumulative Gain Loss After Tax AociLossCashFlowHedgeCumulativeGainLossAfterTax	300000	usd
CY2022Q4	us-gaap	Aoci Loss Cash Flow Hedge Cumulative Gain Loss After Tax AociLossCashFlowHedgeCumulativeGainLossAfterTax	544000	usd
CY2023Q4	us-gaap	Accumulated Other Comprehensive Income Loss Defined Benefit Pension And Other Postretirement Plans Net Of Tax AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax	-303000	usd
CY2022Q4	us-gaap	Accumulated Other Comprehensive Income Loss Defined Benefit Pension And Other Postretirement Plans Net Of Tax AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax	-273000	usd
CY2023Q4	us-gaap	Stockholders Equity StockholdersEquity	243079000	usd
CY2022Q4	us-gaap	Stockholders Equity StockholdersEquity	228923000	usd
CY2023Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	2946698000	usd
CY2022Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	2739178000	usd
CY2023Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	18000000	shares
CY2022Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	18000000	shares
CY2023Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	11098057	shares
CY2023Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	11098057	shares
CY2022Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	11045186	shares
CY2022Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	11045186	shares
CY2023Q4	fnlc	Book Value Per Common Share BookValuePerCommonShare	21.90
CY2022Q4	fnlc	Book Value Per Common Share BookValuePerCommonShare	20.73
CY2023Q4	fnlc	Tangible Book Value Per Common Share TangibleBookValuePerCommonShare	19.12
CY2022Q4	fnlc	Tangible Book Value Per Common Share TangibleBookValuePerCommonShare	17.93
CY2022Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	0	usd
CY2023	fnlc	Interest Incomeand Feeson Loans Tax Exempt InterestIncomeandFeesonLoansTaxExempt	1913000	usd
CY2022	fnlc	Interest Incomeand Feeson Loans Tax Exempt InterestIncomeandFeesonLoansTaxExempt	1181000	usd
CY2021	fnlc	Interest Incomeand Feeson Loans Tax Exempt InterestIncomeandFeesonLoansTaxExempt	1102000	usd
CY2023	us-gaap	Interest And Fee Income Loans And Leases InterestAndFeeIncomeLoansAndLeases	108274000	usd
CY2022	us-gaap	Interest And Fee Income Loans And Leases InterestAndFeeIncomeLoansAndLeases	75805000	usd
CY2021	us-gaap	Interest And Fee Income Loans And Leases InterestAndFeeIncomeLoansAndLeases	62195000	usd
CY2023	us-gaap	Interest Income Deposits With Financial Institutions InterestIncomeDepositsWithFinancialInstitutions	517000	usd
CY2022	us-gaap	Interest Income Deposits With Financial Institutions InterestIncomeDepositsWithFinancialInstitutions	315000	usd
CY2021	us-gaap	Interest Income Deposits With Financial Institutions InterestIncomeDepositsWithFinancialInstitutions	72000	usd
CY2023	us-gaap	Interest Income Securities Tax Exempt InterestIncomeSecuritiesTaxExempt	8032000	usd
CY2022	us-gaap	Interest Income Securities Tax Exempt InterestIncomeSecuritiesTaxExempt	7571000	usd
CY2021	us-gaap	Interest Income Securities Tax Exempt InterestIncomeSecuritiesTaxExempt	7644000	usd
CY2023	us-gaap	Interest And Dividend Income Securities InterestAndDividendIncomeSecurities	19383000	usd
CY2022	us-gaap	Interest And Dividend Income Securities InterestAndDividendIncomeSecurities	16915000	usd
CY2021	us-gaap	Interest And Dividend Income Securities InterestAndDividendIncomeSecurities	14814000	usd
CY2023	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	128174000	usd
CY2022	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	93035000	usd
CY2021	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	77081000	usd
CY2023	us-gaap	Interest Expense Deposits InterestExpenseDeposits	61004000	usd
CY2022	us-gaap	Noninterest Expense NoninterestExpense	43904000	usd
CY2021	us-gaap	Noninterest Expense NoninterestExpense	42148000	usd
CY2023	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	35702000	usd
CY2022	us-gaap	Interest Expense Deposits InterestExpenseDeposits	15359000	usd
CY2021	us-gaap	Interest Expense Deposits InterestExpenseDeposits	7314000	usd
CY2023	us-gaap	Interest Expense Borrowings InterestExpenseBorrowings	1963000	usd
CY2022	us-gaap	Interest Expense Borrowings InterestExpenseBorrowings	1510000	usd
CY2021	us-gaap	Interest Expense Borrowings InterestExpenseBorrowings	3464000	usd
CY2023	us-gaap	Interest Expense InterestExpense	62967000	usd
CY2022	us-gaap	Interest Expense InterestExpense	16869000	usd
CY2021	us-gaap	Interest Expense InterestExpense	10778000	usd
CY2023	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	65207000	usd
CY2022	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	76166000	usd
CY2021	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	66303000	usd
CY2023	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	1330000	usd
CY2022	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	1750000	usd
CY2021	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	-375000	usd
CY2023	us-gaap	Debt Securities Held To Maturity Credit Loss Expense Reversal DebtSecuritiesHeldToMaturityCreditLossExpenseReversal	-4000	usd
CY2022	us-gaap	Debt Securities Held To Maturity Credit Loss Expense Reversal DebtSecuritiesHeldToMaturityCreditLossExpenseReversal	0	usd
CY2021	us-gaap	Debt Securities Held To Maturity Credit Loss Expense Reversal DebtSecuritiesHeldToMaturityCreditLossExpenseReversal	0	usd
CY2023	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	-142000	usd
CY2022	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	0	usd
CY2021	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	0	usd
CY2023	fnlc	Credit Loss Expense Reversal CreditLossExpenseReversal	1184000	usd
CY2022	fnlc	Credit Loss Expense Reversal CreditLossExpenseReversal	1750000	usd
CY2021	fnlc	Credit Loss Expense Reversal CreditLossExpenseReversal	-375000	usd
CY2023	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	64023000	usd
CY2022	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	74416000	usd
CY2021	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	66678000	usd
CY2023	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	0	usd
CY2022	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	7000	usd
CY2021	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	23000	usd
CY2023	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	2699000	usd
CY2022	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	2670000	usd
CY2021	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	2819000	usd
CY2023	us-gaap	Noninterest Income NoninterestIncome	15437000	usd
CY2022	us-gaap	Noninterest Income NoninterestIncome	16874000	usd
CY2021	us-gaap	Noninterest Income NoninterestIncome	19383000	usd
CY2023	us-gaap	Labor And Related Expense LaborAndRelatedExpense	21942000	usd
CY2022	us-gaap	Labor And Related Expense LaborAndRelatedExpense	23316000	usd
CY2021	us-gaap	Labor And Related Expense LaborAndRelatedExpense	21152000	usd
CY2023	us-gaap	Occupancy Net OccupancyNet	3319000	usd
CY2022	us-gaap	Occupancy Net OccupancyNet	3052000	usd
CY2021	us-gaap	Occupancy Net OccupancyNet	2841000	usd
CY2023	us-gaap	Equipment Expense EquipmentExpense	5391000	usd
CY2022	us-gaap	Equipment Expense EquipmentExpense	5058000	usd
CY2023	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	1962000	usd
CY2021	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	69000	usd
CY2022	us-gaap	Other Noninterest Expense OtherNoninterestExpense	11341000	usd
CY2021	us-gaap	Other Noninterest Expense OtherNoninterestExpense	12474000	usd
CY2023	us-gaap	Noninterest Expense NoninterestExpense	43758000	usd
CY2022	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	47386000	usd
CY2021	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	43913000	usd
CY2023	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	6184000	usd
CY2022	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	8396000	usd
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	7644000	usd
CY2023	us-gaap	Net Income Loss NetIncomeLoss	29518000	usd
CY2022	us-gaap	Net Income Loss NetIncomeLoss	38990000	usd
CY2021	us-gaap	Net Income Loss NetIncomeLoss	36269000	usd
CY2023	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.68
CY2022	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	3.56
CY2021	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	3.33
CY2023	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.66
CY2022	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	3.53
CY2021	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	3.30
CY2023	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	5143000	usd
CY2022	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-43000000	usd
CY2021	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-6727000	usd
CY2023	fnlc	Availableforsale Securities Transferredto Heldtomaturity Securities Unrealized Gain Loss AvailableforsaleSecuritiesTransferredtoHeldtomaturitySecuritiesUnrealizedGainLoss	8000	usd
CY2022	fnlc	Availableforsale Securities Transferredto Heldtomaturity Securities Unrealized Gain Loss AvailableforsaleSecuritiesTransferredtoHeldtomaturitySecuritiesUnrealizedGainLoss	23000	usd
CY2021	fnlc	Availableforsale Securities Transferredto Heldtomaturity Securities Unrealized Gain Loss AvailableforsaleSecuritiesTransferredtoHeldtomaturitySecuritiesUnrealizedGainLoss	46000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	-244000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	544000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	4932000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Transition Asset Obligation Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetTransitionAssetObligationNetOfTax	-30000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Transition Asset Obligation Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetTransitionAssetObligationNetOfTax	-168000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Transition Asset Obligation Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetTransitionAssetObligationNetOfTax	-77000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	4937000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-42265000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-1672000	usd
CY2023	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	34455000	usd
CY2022	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	-3275000	usd
CY2020Q4	us-gaap	Stockholders Equity StockholdersEquity	223726000	usd
CY2021	us-gaap	Net Income Loss NetIncomeLoss	36269000	usd
CY2021	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-6727000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	4932000	usd
CY2021	fnlc	Availableforsale Securities Transferredto Heldtomaturity Securities Unrealized Gain Loss AvailableforsaleSecuritiesTransferredtoHeldtomaturitySecuritiesUnrealizedGainLoss	46000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-77000	usd
CY2021	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	34597000	usd
CY2021	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.27
CY2021	us-gaap	Dividends Cash DividendsCash	13958000	usd
CY2021	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	856000	usd
CY2021	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	253000	usd
CY2021	us-gaap	Stock Issued During Period Value New Issues StockIssuedDuringPeriodValueNewIssues	689000	usd
CY2021Q4	us-gaap	Stockholders Equity StockholdersEquity	245657000	usd
CY2022	us-gaap	Net Income Loss NetIncomeLoss	38990000	usd
CY2022	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-43000000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	544000	usd
CY2022	fnlc	Availableforsale Securities Transferredto Heldtomaturity Securities Unrealized Gain Loss AvailableforsaleSecuritiesTransferredtoHeldtomaturitySecuritiesUnrealizedGainLoss	23000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-168000	usd
CY2022	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	-3275000	usd
CY2022	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.34
CY2022	us-gaap	Dividends Cash DividendsCash	14787000	usd
CY2022	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	809000	usd
CY2022	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	277000	usd
CY2022	us-gaap	Stock Issued During Period Value New Issues StockIssuedDuringPeriodValueNewIssues	796000	usd
CY2022Q4	us-gaap	Stockholders Equity StockholdersEquity	228923000	usd
CY2022Q4	us-gaap	Stockholders Equity StockholdersEquity	228923000	usd
CY2023	us-gaap	Net Income Loss NetIncomeLoss	29518000	usd
CY2023	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	5143000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	-244000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	-244000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-30000	usd
CY2023	us-gaap	Stock Issued During Period Value New Issues StockIssuedDuringPeriodValueNewIssues	817000	usd
CY2023Q4	us-gaap	Stockholders Equity StockholdersEquity	243079000	usd
CY2022	us-gaap	Net Income Loss NetIncomeLoss	38990000	usd
CY2021	us-gaap	Net Income Loss NetIncomeLoss	36269000	usd
CY2023	us-gaap	Depreciation Depreciation	2107000	usd
CY2022	us-gaap	Depreciation Depreciation	1984000	usd
CY2021	us-gaap	Depreciation Depreciation	2039000	usd
CY2023	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-1360000	usd
CY2022	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-127000	usd
CY2021	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	999000	usd
CY2023	fnlc	Credit Loss Expense Reversal CreditLossExpenseReversal	1184000	usd
CY2022	fnlc	Credit Loss Expense Reversal CreditLossExpenseReversal	1750000	usd
CY2021	fnlc	Credit Loss Expense Reversal CreditLossExpenseReversal	-375000	usd
CY2023	us-gaap	Payments For Origination Of Mortgage Loans Held For Sale PaymentsForOriginationOfMortgageLoansHeldForSale	3916000	usd
CY2022	us-gaap	Payments For Origination Of Mortgage Loans Held For Sale PaymentsForOriginationOfMortgageLoansHeldForSale	21554000	usd
CY2021	us-gaap	Payments For Origination Of Mortgage Loans Held For Sale PaymentsForOriginationOfMortgageLoansHeldForSale	106393000	usd
CY2023	us-gaap	Proceeds From Sale Of Loans Held For Sale ProceedsFromSaleOfLoansHeldForSale	4283000	usd
CY2022	us-gaap	Proceeds From Sale Of Loans Held For Sale ProceedsFromSaleOfLoansHeldForSale	22520000	usd
CY2021	us-gaap	Proceeds From Sale Of Loans Held For Sale ProceedsFromSaleOfLoansHeldForSale	114491000	usd
CY2023	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	92000	usd
CY2022	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	406000	usd
CY2021	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	3078000	usd
CY2023	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	0	usd
CY2022	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	7000	usd
CY2021	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	23000	usd
CY2023	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-111000	usd
CY2022	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-914000	usd
CY2021	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-2351000	usd
CY2023	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	42000	usd
CY2022	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	-1000	usd
CY2021	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	91000	usd
CY2023	us-gaap	Share Based Compensation ShareBasedCompensation	820000	usd
CY2022	us-gaap	Share Based Compensation ShareBasedCompensation	809000	usd
CY2021	us-gaap	Share Based Compensation ShareBasedCompensation	856000	usd
CY2023	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	680000	usd
CY2022	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	21443000	usd
CY2021	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	-18604000	usd
CY2023	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	4624000	usd
CY2022	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	17423000	usd
CY2021	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	-9332000	usd
CY2023	us-gaap	Gain Loss On Disposition Of Assets GainLossOnDispositionOfAssets	-33000	usd
CY2022	us-gaap	Gain Loss On Disposition Of Assets GainLossOnDispositionOfAssets	15000	usd
CY2021	us-gaap	Gain Loss On Disposition Of Assets GainLossOnDispositionOfAssets	2000	usd
CY2023	us-gaap	Other Depreciation And Amortization OtherDepreciationAndAmortization	303000	usd
CY2022	us-gaap	Other Depreciation And Amortization OtherDepreciationAndAmortization	305000	usd
CY2021	us-gaap	Other Depreciation And Amortization OtherDepreciationAndAmortization	309000	usd
CY2023	us-gaap	Amortization Of Acquisition Costs AmortizationOfAcquisitionCosts	26000	usd
CY2022	us-gaap	Amortization Of Acquisition Costs AmortizationOfAcquisitionCosts	69000	usd
CY2021	us-gaap	Amortization Of Acquisition Costs AmortizationOfAcquisitionCosts	69000	usd
CY2023	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	36919000	usd
CY2022	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	41213000	usd
CY2021	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	56693000	usd
CY2023	fnlc	Interest Bearing Deposits In Other Banks InterestBearingDepositsInOtherBanks	-205000	usd
CY2022	fnlc	Interest Bearing Deposits In Other Banks InterestBearingDepositsInOtherBanks	-62985000	usd
CY2021	fnlc	Interest Bearing Deposits In Other Banks InterestBearingDepositsInOtherBanks	10527000	usd
CY2023	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	0	usd
CY2022	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	1301000	usd
CY2021	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	19240000	usd
CY2023	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	97524000	usd
CY2022	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	42005000	usd
CY2021	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	104424000	usd
CY2023	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	8149000	usd
CY2022	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	16544000	usd
CY2021	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	80217000	usd
CY2023	us-gaap	Proceeds From Sale Of Other Real Estate ProceedsFromSaleOfOtherRealEstate	106000	usd
CY2022	us-gaap	Proceeds From Sale Of Other Real Estate ProceedsFromSaleOfOtherRealEstate	50000	usd
CY2021	us-gaap	Proceeds From Sale Of Other Real Estate ProceedsFromSaleOfOtherRealEstate	999000	usd
CY2023	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	88581000	usd
CY2022	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	62336000	usd
CY2021	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	141222000	usd
CY2023	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	0	usd
CY2022	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	40621000	usd
CY2021	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	85061000	usd
CY2023	fnlc	Redemption Of Restricted Equity Securities RedemptionOfRestrictedEquitySecurities	498000	usd
CY2022	fnlc	Redemption Of Restricted Equity Securities RedemptionOfRestrictedEquitySecurities	1482000	usd
CY2021	fnlc	Redemption Of Restricted Equity Securities RedemptionOfRestrictedEquitySecurities	5180000	usd
CY2023	us-gaap	Payments To Acquire Finance Receivables PaymentsToAcquireFinanceReceivables	215077000	usd
CY2022	us-gaap	Payments To Acquire Finance Receivables PaymentsToAcquireFinanceReceivables	267624000	usd
CY2021	us-gaap	Payments To Acquire Finance Receivables PaymentsToAcquireFinanceReceivables	171245000	usd
CY2023	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	2635000	usd
CY2022	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	1404000	usd
CY2021	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	3757000	usd
CY2023	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	3000	usd
CY2022	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	38000	usd
CY2021	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	3000	usd
CY2023	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-199808000	usd
CY2022	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-247580000	usd
CY2021	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-201749000	usd
CY2023	fnlc	Increase Decreasein Demand Deposits Savings Depositsand Money Market Accounts IncreaseDecreaseinDemandDepositsSavingsDepositsandMoneyMarketAccounts	18209000	usd
CY2022	fnlc	Increase Decreasein Demand Deposits Savings Depositsand Money Market Accounts IncreaseDecreaseinDemandDepositsSavingsDepositsandMoneyMarketAccounts	-45886000	usd
CY2021	fnlc	Increase Decreasein Demand Deposits Savings Depositsand Money Market Accounts IncreaseDecreaseinDemandDepositsSavingsDepositsandMoneyMarketAccounts	318066000	usd
CY2023	us-gaap	Increase Decrease In Time Deposits IncreaseDecreaseInTimeDeposits	202576000	usd
CY2022	us-gaap	Increase Decrease In Time Deposits IncreaseDecreaseInTimeDeposits	301466000	usd
CY2021	us-gaap	Increase Decrease In Time Deposits IncreaseDecreaseInTimeDeposits	-39380000	usd
CY2023	us-gaap	Repayments Of Other Long Term Debt RepaymentsOfOtherLongTermDebt	84000	usd
CY2022	us-gaap	Repayments Of Other Long Term Debt RepaymentsOfOtherLongTermDebt	55007000	usd
CY2021	us-gaap	Repayments Of Other Long Term Debt RepaymentsOfOtherLongTermDebt	7000	usd
CY2023	us-gaap	Proceeds From Repayments Of Short Term Debt ProceedsFromRepaymentsOfShortTermDebt	-33747000	usd
CY2022	us-gaap	Proceeds From Repayments Of Short Term Debt ProceedsFromRepaymentsOfShortTermDebt	22148000	usd
CY2021	us-gaap	Proceeds From Repayments Of Short Term Debt ProceedsFromRepaymentsOfShortTermDebt	-125689000	usd
CY2023	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	250000	usd
CY2022	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	277000	usd
CY2021	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	253000	usd
CY2023	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	817000	usd
CY2022	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	796000	usd
CY2021	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	689000	usd
CY2023	us-gaap	Payments Of Dividends PaymentsOfDividends	15418000	usd
CY2022	us-gaap	Payments Of Dividends PaymentsOfDividends	14779000	usd
CY2021	us-gaap	Payments Of Dividends PaymentsOfDividends	13948000	usd
CY2023	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	172103000	usd
CY2022	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	208461000	usd
CY2021	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	139478000	usd
CY2023	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	9214000	usd
CY2022	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	2094000	usd
CY2021	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-5578000	usd
CY2022Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	22728000	usd
CY2021Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	20634000	usd
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	26212000	usd
CY2023Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	31942000	usd
CY2022Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	22728000	usd
CY2021Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	20634000	usd
CY2023	us-gaap	Interest Paid Net InterestPaidNet	62228000	usd
CY2022	us-gaap	Interest Paid Net InterestPaidNet	16068000	usd
CY2021	us-gaap	Interest Paid Net InterestPaidNet	11141000	usd
CY2023	us-gaap	Income Taxes Paid IncomeTaxesPaid	5621000	usd
CY2022	us-gaap	Income Taxes Paid IncomeTaxesPaid	8010000	usd
CY2021	us-gaap	Income Taxes Paid IncomeTaxesPaid	6548000	usd
CY2023	us-gaap	Transfer Of Other Real Estate TransferOfOtherRealEstate	0	usd
CY2022	us-gaap	Transfer Of Other Real Estate TransferOfOtherRealEstate	0	usd
CY2021	us-gaap	Transfer Of Other Real Estate TransferOfOtherRealEstate	0	usd
CY2023	fnlc	Increase Decrease In Net Unrealized Gain Loss On Available For Sale Securities Net Of Tax IncreaseDecreaseInNetUnrealizedGainLossOnAvailableForSaleSecuritiesNetOfTax	5143000	usd
CY2022	fnlc	Increase Decrease In Net Unrealized Gain Loss On Available For Sale Securities Net Of Tax IncreaseDecreaseInNetUnrealizedGainLossOnAvailableForSaleSecuritiesNetOfTax	-43000000	usd
CY2021	fnlc	Increase Decrease In Net Unrealized Gain Loss On Available For Sale Securities Net Of Tax IncreaseDecreaseInNetUnrealizedGainLossOnAvailableForSaleSecuritiesNetOfTax	-6727000	usd
CY2023Q4	fnlc	Number Of Offices NumberOfOffices	18	office
CY2023	us-gaap	Use Of Estimates UseOfEstimates	<div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Use of Estimates in Preparation of Financial Statements</span></div><div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In preparing the financial statements in accordance with GAAP, Management is required to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities as of the date of the balance sheet and revenues and expenses for the reporting period. Actual results could differ significantly from those estimates. Material estimates that are particularly susceptible to significant change in the near-term relate to the determination of the ACL, the valuations of mortgage servicing rights, derivative financial instruments, debt securities in an unrealized loss position, and goodwill.</span></div>
CY2023Q4	us-gaap	Debt Securities Available For Sale Amortized Cost Excluding Accrued Interest After Allowance For Credit Loss DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLoss	332148000	usd
CY2023Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	310000	usd
CY2023Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	50405000	usd
CY2023	us-gaap	Derivatives Methods Of Accounting Hedging Derivatives DerivativesMethodsOfAccountingHedgingDerivatives	<div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Derivative Financial Instruments Designated as Hedges</span></div><div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Company recognizes all derivatives in the consolidated balance sheets at fair value. On the date a derivative contract is entered into, the derivative is designated as a hedge of either a forecasted transaction or the variability of cash flows to be received or paid related to a recognized asset or liability (“cash flow hedge”), a hedge of the fair value of a recognized asset or liability or of an unrecognized firm commitment (“fair value hedge”), or a held for trading instrument (“trading instrument”). The relationships between hedging instruments and hedged items is formally documented, as is the risk management objectives and strategy for undertaking various hedge transactions. Both at the hedge’s inception and on an ongoing basis, determination is made as to whether the derivatives that are used in hedging transactions are effective in offsetting changes in cash flows or fair values of hedged items. Changes in fair value of a derivative that is effective and that qualifies as a cash flow hedge are recorded in OCI and are reclassified into earnings when the forecasted transaction or related cash flows affect earnings. Changes in fair value of a derivative that qualifies as a fair value hedge and the change in fair value of the hedged item are both recorded in earnings and offset each other when the transaction is effective. Those derivatives that are classified as trading instruments, including customer loan swaps, are recorded at fair value with changes in fair value recorded in earnings. Hedge accounting is discontinued when it is determined that the derivative is no longer effective in offsetting changes in the cash flows of the hedged item, that it is unlikely that the forecasted transaction will occur, or that the designation of the derivative as a hedging instrument is no longer appropriate.</span></div>
CY2023	us-gaap	Financing Receivable Allowance For Credit Losses Policy For Uncollectible Amounts FinancingReceivableAllowanceForCreditLossesPolicyForUncollectibleAmounts	<div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Allowance for Credit Losses</span></div><div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Management believes the ACL requires the most significant estimates and assumptions used in the preparation of the consolidated financial statements. The ACL is based on Management's evaluation of the level of the allowance required in relation to the estimated loss exposure in the loan and investment portfolios. The allowance is comprised of the ACL on loans, the ACL on off balance sheet commitments, and the ACL on held to maturity securities. Management regularly evaluates the allowance, typically monthly, to determine the appropriate level by taking into consideration factors such as the size and growth trajectory of the portfolios, quality trends as measured by key indicators, prior loan loss experience in each loan portfolio segment, local and national business and economic conditions, and other factors contributing to Management's estimation of potential losses. The use of different estimates or assumptions could produce different provisions for credit losses.</span></div>
CY2023Q4	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest DebtSecuritiesAvailableForSaleExcludingAccruedInterest	282053000	usd
CY2023	us-gaap	Goodwill And Intangible Asset Impairment GoodwillAndIntangibleAssetImpairment	0	usd
CY2023	fnlc	Mortgage Servicing Rights Fee Percentage MortgageServicingRightsFeePercentage	0.0025
CY2023	us-gaap	Number Of Operating Segments NumberOfOperatingSegments	1	segment
CY2023Q4	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest Before Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss	385669000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	383000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	47482000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	338570000	usd
CY2023Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	434000	usd
CY2023Q4	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest After Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss	385235000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	383000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	47482000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	338570000	usd
CY2023Q4	us-gaap	Federal Home Loan Bank Stock FederalHomeLoanBankStock	2348000	usd
CY2023Q4	us-gaap	Federal Home Loan Bank Stock FederalHomeLoanBankStock	2348000	usd
CY2023Q4	us-gaap	Federal Reserve Bank Stock FederalReserveBankStock	1037000	usd
CY2023Q4	us-gaap	Federal Reserve Bank Stock FederalReserveBankStock	1037000	usd
CY2023Q4	us-gaap	Federal Home Loan Bank Stock And Federal Reserve Bank Stock FederalHomeLoanBankStockAndFederalReserveBankStock	3385000	usd
CY2023Q4	us-gaap	Federal Home Loan Bank Stock And Federal Reserve Bank Stock FederalHomeLoanBankStockAndFederalReserveBankStock	3385000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Amortized Cost Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest	0	usd
CY2023Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	434000	usd
CY2022Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	0	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Amortized Cost Excluding Accrued Interest After Allowance For Credit Loss DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLoss	341113000	usd
CY2022Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	57000	usd
CY2022Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	56661000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest DebtSecuritiesAvailableForSaleExcludingAccruedInterest	284509000	usd
CY2022Q4	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest Before Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss	393896000	usd
CY2022Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	200000	usd
CY2022Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	55085000	usd
CY2022Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	339011000	usd
CY2022Q4	us-gaap	Federal Home Loan Bank Stock FederalHomeLoanBankStock	2846000	usd
CY2022Q4	us-gaap	Federal Home Loan Bank Stock FederalHomeLoanBankStock	2846000	usd
CY2022Q4	us-gaap	Federal Reserve Bank Stock FederalReserveBankStock	1037000	usd
CY2022Q4	us-gaap	Federal Reserve Bank Stock FederalReserveBankStock	1037000	usd
CY2022Q4	us-gaap	Federal Home Loan Bank Stock And Federal Reserve Bank Stock FederalHomeLoanBankStockAndFederalReserveBankStock	3883000	usd
CY2022Q4	us-gaap	Federal Home Loan Bank Stock And Federal Reserve Bank Stock FederalHomeLoanBankStockAndFederalReserveBankStock	3883000	usd
CY2023Q4	us-gaap	Available For Sale Securities Debt Maturities Within One Year Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost	0	usd
CY2023Q4	us-gaap	Available For Sale Securities Debt Maturities Within One Year Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue	0	usd
CY2023Q4	us-gaap	Held To Maturity Securities Debt Maturities Within One Year Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount	1674000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Debt Maturities Within One Year Fair Value HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue	1672000	usd
CY2023Q4	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost	3489000	usd
CY2023Q4	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	3373000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Debt Maturities After One Through Five Years Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsNetCarryingAmount	16387000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Debt Maturities After One Through Five Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	15814000	usd
CY2023Q4	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost	28551000	usd
CY2023Q4	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	25089000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Debt Maturities After Five Through Ten Years Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsNetCarryingAmount	99942000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Debt Maturities After Five Through Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	93894000	usd
CY2023Q4	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost	300108000	usd
CY2023Q4	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue	253591000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Debt Maturities After Ten Years Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsNetCarryingAmount	267666000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Debt Maturities After Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue	227190000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Amortized Cost Excluding Accrued Interest After Allowance For Credit Loss DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLoss	332148000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest DebtSecuritiesAvailableForSaleExcludingAccruedInterest	282053000	usd
CY2023Q4	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest Before Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss	385669000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	338570000	usd
CY2022Q4	us-gaap	Available For Sale Securities Debt Maturities Within One Year Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost	0	usd
CY2022Q4	us-gaap	Available For Sale Securities Debt Maturities Within One Year Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue	0	usd
CY2022Q4	us-gaap	Held To Maturity Securities Debt Maturities Within One Year Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount	1787000	usd
CY2022Q4	us-gaap	Held To Maturity Securities Debt Maturities Within One Year Fair Value HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue	1782000	usd
CY2022Q4	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost	3609000	usd
CY2022Q4	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	3409000	usd
CY2022Q4	us-gaap	Held To Maturity Securities Debt Maturities After One Through Five Years Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsNetCarryingAmount	14998000	usd
CY2022Q4	us-gaap	Held To Maturity Securities Debt Maturities After One Through Five Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	14480000	usd
CY2022Q4	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost	18591000	usd
CY2022Q4	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	15203000	usd
CY2022Q4	us-gaap	Held To Maturity Securities Debt Maturities After Five Through Ten Years Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsNetCarryingAmount	86833000	usd
CY2022Q4	us-gaap	Held To Maturity Securities Debt Maturities After Five Through Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	81443000	usd
CY2022Q4	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost	318913000	usd
CY2022Q4	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue	265897000	usd
CY2022Q4	us-gaap	Held To Maturity Securities Debt Maturities After Ten Years Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsNetCarryingAmount	290278000	usd
CY2022Q4	us-gaap	Held To Maturity Securities Debt Maturities After Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue	241306000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Amortized Cost Excluding Accrued Interest After Allowance For Credit Loss DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLoss	341113000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest DebtSecuritiesAvailableForSaleExcludingAccruedInterest	284509000	usd
CY2022Q4	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest Before Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss	393896000	usd
CY2022Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	339011000	usd
CY2023	us-gaap	Proceeds From Sale And Maturity Of Marketable Securities ProceedsFromSaleAndMaturityOfMarketableSecurities	0	usd
CY2022	us-gaap	Proceeds From Sale And Maturity Of Marketable Securities ProceedsFromSaleAndMaturityOfMarketableSecurities	1301000	usd
CY2021	us-gaap	Proceeds From Sale And Maturity Of Marketable Securities ProceedsFromSaleAndMaturityOfMarketableSecurities	19240000	usd
CY2023	fnlc	Debt Securities Realized Gain DebtSecuritiesRealizedGain	0	usd
CY2022	fnlc	Debt Securities Realized Gain DebtSecuritiesRealizedGain	8000	usd
CY2021	fnlc	Debt Securities Realized Gain DebtSecuritiesRealizedGain	628000	usd
CY2023	fnlc	Debt Securities Realized Loss DebtSecuritiesRealizedLoss	0	usd
CY2022	fnlc	Debt Securities Realized Loss DebtSecuritiesRealizedLoss	1000	usd
CY2021	fnlc	Debt Securities Realized Loss DebtSecuritiesRealizedLoss	605000	usd
CY2023	us-gaap	Debt Securities Gain Loss DebtSecuritiesGainLoss	0	usd
CY2022	us-gaap	Debt Securities Gain Loss DebtSecuritiesGainLoss	7000	usd
CY2021	us-gaap	Debt Securities Gain Loss DebtSecuritiesGainLoss	23000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	0	usd
CY2022	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	1000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	5000	usd
CY2023Q4	fnlc	Number Of Securities Temporarily Impaired NumberOfSecuritiesTemporarilyImpaired	226	security
CY2023Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	3794000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	63000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	257711000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	50342000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	261505000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	50405000	usd
CY2022Q4	fnlc	Number Of Securities Temporarily Impaired NumberOfSecuritiesTemporarilyImpaired	869	security
CY2022Q4	fnlc	Number Of Securities Temporarily Impaired Twelve Months NumberOfSecuritiesTemporarilyImpairedTwelveMonths	300	security
CY2022	fnlc	Length Of Time Securities Temporarily Impaired LengthOfTimeSecuritiesTemporarilyImpaired	P12M
CY2022Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	251182000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	23126000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	310159000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	88620000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	561341000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	111746000	usd
CY2022Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	0	usd
CY2023	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest Credit Loss Expense Reversal DebtSecuritiesHeldToMaturityExcludingAccruedInterestCreditLossExpenseReversal	-4000	usd
CY2023	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest Allowance For Credit Loss Writeoff DebtSecuritiesHeldToMaturityExcludingAccruedInterestAllowanceForCreditLossWriteoff	0	usd
CY2023	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest Allowance For Credit Loss Recovery DebtSecuritiesHeldToMaturityExcludingAccruedInterestAllowanceForCreditLossRecovery	0	usd
CY2023Q4	us-gaap	Financing Receivable Threshold Period Past Due FinancingReceivableThresholdPeriodPastDue	P30D
CY2023Q4	us-gaap	Debt Securities Held To Maturity Nonaccrual DebtSecuritiesHeldToMaturityNonaccrual	0	usd
CY2014Q3	fnlc	Availablefor Sale Securities Transferred Securityat Carrying Value AvailableforSaleSecuritiesTransferredSecurityatCarryingValue	89780000	usd
CY2014Q3	fnlc	Availablefor Sale Securities Transferred Securityat Fair Value AvailableforSaleSecuritiesTransferredSecurityatFairValue	89757000	usd
CY2014Q3	fnlc	Availableforsale Securities Transferredto Heldtomaturity Securities Accumulated Unrealized Gain Loss AvailableforsaleSecuritiesTransferredtoHeldtomaturitySecuritiesAccumulatedUnrealizedGainLoss	-15000	usd
CY2023Q4	fnlc	Other Comprehensive Income Loss Accumulated Unrealized Gain Losson Transferof Availableforsale Securitiesto Heldtomaturity OtherComprehensiveIncomeLossAccumulatedUnrealizedGainLossonTransferofAvailableforsaleSecuritiestoHeldtomaturity	-56000	usd
CY2022Q4	fnlc	Other Comprehensive Income Loss Accumulated Unrealized Gain Losson Transferof Availableforsale Securitiesto Heldtomaturity OtherComprehensiveIncomeLossAccumulatedUnrealizedGainLossonTransferofAvailableforsaleSecuritiestoHeldtomaturity	-64000	usd
CY2023Q4	fnlc	Number Of States In New England Where Fhlb Serve NumberOfStatesInNewEnglandWhereFhlbServe	6	state
CY2023Q4	us-gaap	Federal Home Loan Bank Stock FederalHomeLoanBankStock	2348000	usd
CY2022Q4	us-gaap	Federal Home Loan Bank Stock FederalHomeLoanBankStock	2846000	usd
CY2022Q4	us-gaap	Federal Reserve Bank Stock FederalReserveBankStock	1037000	usd
CY2023Q4	us-gaap	Federal Reserve Bank Stock FederalReserveBankStock	1037000	usd
CY2023Q4	fnlc	Restricted Equity Securities Unrealized Losses RestrictedEquitySecuritiesUnrealizedLosses	0	usd
CY2023Q4	fnlc	Residential Mortgage Loans Serviced For Others Outstanding Principal ResidentialMortgageLoansServicedForOthersOutstandingPrincipal	321178000	usd
CY2022Q4	fnlc	Residential Mortgage Loans Serviced For Others Outstanding Principal ResidentialMortgageLoansServicedForOthersOutstandingPrincipal	342870000	usd
CY2023	fnlc	Net Gain From Sale Of Loans NetGainFromSaleOfLoans	92000	usd
CY2022	fnlc	Net Gain From Sale Of Loans NetGainFromSaleOfLoans	406000	usd
CY2021	fnlc	Net Gain From Sale Of Loans NetGainFromSaleOfLoans	3078000	usd
CY2023	us-gaap	Servicing Asset At Fair Value Additions ServicingAssetAtFairValueAdditions	48000	usd
CY2023	us-gaap	Amortization Of Mortgage Servicing Rights Ms Rs AmortizationOfMortgageServicingRightsMSRs	364000	usd
CY2023Q4	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	3583000	usd
CY2022	us-gaap	Servicing Asset At Fair Value Additions ServicingAssetAtFairValueAdditions	312000	usd
CY2022	us-gaap	Amortization Of Mortgage Servicing Rights Ms Rs AmortizationOfMortgageServicingRightsMSRs	517000	usd
CY2022Q4	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	3734000	usd
CY2023	fnlc	Movingaverageofweeklyprepaymentdata Movingaverageofweeklyprepaymentdata	P3M
CY2023	us-gaap	Servicing Assets And Servicing Liabilities At Fair Value Assumptions Used To Estimate Fair Value Prepayment Speed ServicingAssetsAndServicingLiabilitiesAtFairValueAssumptionsUsedToEstimateFairValuePrepaymentSpeed	0.0470
CY2023	fnlc	Servicing Assets And Servicing Liabilities At Fair Value Assumptions Used To Estimate Fair Value Discount Rate Adjustment Factor ServicingAssetsAndServicingLiabilitiesAtFairValueAssumptionsUsedToEstimateFairValueDiscountRateAdjustmentFactor	0.0900
CY2023Q4	fnlc	Mortgage Servicing Rights Gross MortgageServicingRightsGross	8702000	usd
CY2022Q4	fnlc	Mortgage Servicing Rights Gross MortgageServicingRightsGross	8654000	usd
CY2023Q4	fnlc	Accumulated Amortization Mortgage Servicing Rights AccumulatedAmortizationMortgageServicingRights	6525000	usd
CY2022Q4	fnlc	Accumulated Amortization Mortgage Servicing Rights AccumulatedAmortizationMortgageServicingRights	6161000	usd
CY2023Q4	us-gaap	Servicing Asset At Amortized Value Fair Value ServicingAssetAtAmortizedValueFairValue	2177000	usd
CY2022Q4	us-gaap	Servicing Asset At Amortized Value Fair Value ServicingAssetAtAmortizedValueFairValue	2493000	usd
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	2129454000	usd
CY2023Q4	fnlc	Percentage Of Loans Receivable By Type PercentageOfLoansReceivableByType	1.000
CY2022Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	1914674000	usd
CY2022Q4	fnlc	Percentage Of Loans Receivable By Type PercentageOfLoansReceivableByType	1.000
CY2023Q4	us-gaap	Financing Receivable Deferred Income FinancingReceivableDeferredIncome	11479000	usd
CY2022Q4	us-gaap	Financing Receivable Deferred Income FinancingReceivableDeferredIncome	10132000	usd
CY2023Q4	us-gaap	Federal Home Loan Bank Advances General Debt Obligations Disclosures Collateral Pledged1 FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledged1	561574000	usd
CY2022Q4	us-gaap	Federal Home Loan Bank Advances General Debt Obligations Disclosures Collateral Pledged1 FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledged1	475233000	usd
CY2022Q3	fnlc	Number Of Loans Sold NumberOfLoansSold	41	loan
CY2022Q3	fnlc	Financing Receivable Past Due Non Accrual And Trouble Debt Restructure Loan Sold FinancingReceivablePastDueNonAccrualAndTroubleDebtRestructureLoanSold	5200000	usd
CY2023Q4	us-gaap	Loans And Leases Receivable Related Parties LoansAndLeasesReceivableRelatedParties	54425000	usd
CY2022Q4	us-gaap	Loans And Leases Receivable Related Parties LoansAndLeasesReceivableRelatedParties	48001000	usd
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	2129454000	usd
CY2023Q4	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	429000	usd
CY2022Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	1914674000	usd
CY2022Q4	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	241000	usd
CY2023Q4	fnlc	Financing Receivable Nonaccrual With Allowance FinancingReceivableNonaccrualWithAllowance	658000	usd
CY2023Q4	us-gaap	Financing Receivable Nonaccrual No Allowance FinancingReceivableNonaccrualNoAllowance	1520000	usd
CY2023Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	2178000	usd
CY2022Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	1755000	usd
CY2023	us-gaap	Loans And Leases Receivable Impaired Interest Lost On Nonaccrual Loans LoansAndLeasesReceivableImpairedInterestLostOnNonaccrualLoans	142000	usd
CY2022	us-gaap	Loans And Leases Receivable Impaired Interest Lost On Nonaccrual Loans LoansAndLeasesReceivableImpairedInterestLostOnNonaccrualLoans	223000	usd
CY2023Q4	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	429000	usd
CY2022Q4	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	241000	usd
CY2022Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment	4359000	usd
CY2022Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance	4942000	usd
CY2022	us-gaap	Impaired Financing Receivable With No Related Allowance Average Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment	6732000	usd
CY2022	fnlc	Impaired Financing Receivable With No Related Allowance Interest Income ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncome	154000	usd
CY2022Q4	us-gaap	Impaired Financing Receivable With Related Allowance Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment	1801000	usd
CY2022Q4	us-gaap	Impaired Financing Receivable With Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance	1906000	usd
CY2022Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	398000	usd
CY2022	us-gaap	Impaired Financing Receivable With Related Allowance Average Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment	2804000	usd
CY2022	fnlc	Impaired Financing Receivable With Related Allowance Interest Income ImpairedFinancingReceivableWithRelatedAllowanceInterestIncome	50000	usd
CY2022Q4	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	6160000	usd
CY2022Q4	us-gaap	Impaired Financing Receivable Unpaid Principal Balance ImpairedFinancingReceivableUnpaidPrincipalBalance	6848000	usd
CY2022Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	398000	usd
CY2022	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	9536000	usd
CY2022	fnlc	Impaired Financing Receivable Interest Income ImpairedFinancingReceivableInterestIncome	204000	usd
CY2021Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment	8968000	usd
CY2021Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance	10453000	usd
CY2021	us-gaap	Impaired Financing Receivable With No Related Allowance Average Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment	9553000	usd
CY2021	fnlc	Impaired Financing Receivable With No Related Allowance Interest Income ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncome	166000	usd
CY2021Q4	us-gaap	Impaired Financing Receivable With Related Allowance Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment	3084000	usd
CY2021Q4	us-gaap	Impaired Financing Receivable With Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance	3307000	usd
CY2021Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	576000	usd
CY2021	us-gaap	Impaired Financing Receivable With Related Allowance Average Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment	3568000	usd
CY2021	fnlc	Impaired Financing Receivable With Related Allowance Interest Income ImpairedFinancingReceivableWithRelatedAllowanceInterestIncome	76000	usd
CY2021Q4	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	12052000	usd
CY2021Q4	us-gaap	Impaired Financing Receivable Unpaid Principal Balance ImpairedFinancingReceivableUnpaidPrincipalBalance	13760000	usd
CY2021Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	576000	usd
CY2021	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	13121000	usd
CY2021	fnlc	Impaired Financing Receivable Interest Income ImpairedFinancingReceivableInterestIncome	242000	usd
CY2022	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	29	loan
CY2022Q4	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	4744000	usd
CY2022	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	29	loan
CY2022Q4	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	4744000	usd
CY2023	us-gaap	Financing Receivable Excluding Accrued Interest Credit Loss Expense Reversal FinancingReceivableExcludingAccruedInterestCreditLossExpenseReversal	1330000	usd
CY2023Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	24030000	usd
CY2021Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	15521000	usd
CY2022	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Writeoff FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff	758000	usd
CY2022	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Recovery FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossRecovery	210000	usd
CY2022Q4	fnlc	Troubled Debt Restructuring Loansand Leases Receivable Specific Allowance TroubledDebtRestructuringLoansandLeasesReceivableSpecificAllowance	181000	usd
CY2022Q4	fnlc	Financing Receivable Modifications Number Of Contracts Greater Than30 Days Past Due Place In Tdr In Previous12 Months FinancingReceivableModificationsNumberOfContractsGreaterThan30DaysPastDuePlaceInTDRInPrevious12Months	1	loan
CY2022Q4	fnlc	Financing Receivable Recorded Investment Greater Than30 Days Past Due FinancingReceivableRecordedInvestmentGreaterThan30DaysPastDue	97000	usd
CY2022Q4	fnlc	Financing Receivable Modifications Number Of Contracts Greater Than30 Days Past Due Place In Tdr In Previous12 Months FinancingReceivableModificationsNumberOfContractsGreaterThan30DaysPastDuePlaceInTDRInPrevious12Months	1	loan
CY2022Q4	fnlc	Financing Receivable Recorded Investment Greater Than30 Days Past Due Placed In Tdr In Previous12 Months FinancingReceivableRecordedInvestmentGreaterThan30DaysPastDuePlacedInTDRInPrevious12Months	97000	usd
CY2022Q4	fnlc	Financing Receivable Recorded Investment Greaterthan30 Days Past Due Placedin Td Rin Previous12 Months Specific Allowanceduring Period FinancingReceivableRecordedInvestmentGreaterthan30DaysPastDuePlacedinTDRinPrevious12MonthsSpecificAllowanceduringPeriod	0	usd
CY2022	fnlc	Financing Receivable Modifications Number Of Contracts During Period FinancingReceivableModificationsNumberOfContractsDuringPeriod	1	loan
CY2022	fnlc	Financing Receivable Modifications Number Of Contracts During Period FinancingReceivableModificationsNumberOfContractsDuringPeriod	1	loan
CY2022	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	38000	usd
CY2022	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	38000	usd
CY2022	fnlc	Troubled Debt Restructuring Loans And Leases Receivable Specific Allowance Current Period TroubledDebtRestructuringLoansAndLeasesReceivableSpecificAllowanceCurrentPeriod	0	usd
CY2022Q4	fnlc	Financing Receivable Modifications Number Of Contracts Involved In Bankruptcy During Period FinancingReceivableModificationsNumberOfContractsInvolvedInBankruptcyDuringPeriod	4	loan
CY2022Q4	fnlc	Financing Receivable Loans Classified As Troubled Debt Restructurings That Are Involved In Bankruptcy FinancingReceivableLoansClassifiedAsTroubledDebtRestructuringsThatAreInvolvedInBankruptcy	550000	usd
CY2022Q4	fnlc	Financing Receivable Number Of Loans Classified As Troubled Debt Restructurings That Were On Non Accrual Status FinancingReceivableNumberOfLoansClassifiedAsTroubledDebtRestructuringsThatWereOnNonAccrualStatus	5	loan
CY2022Q4	fnlc	Financing Receivable Loans Classified As Troubled Debt Restructurings That Were On Non Accrual Status FinancingReceivableLoansClassifiedAsTroubledDebtRestructuringsThatWereOnNonAccrualStatus	339000	usd
CY2022Q4	fnlc	Loans Classified As Troubled Debt Restructurings That Are Involved In Foreclosure LoansClassifiedAsTroubledDebtRestructuringsThatAreInvolvedInForeclosure	0	usd
CY2023Q4	fnlc	Mortgage Loansin Processof Foreclosure Number MortgageLoansinProcessofForeclosureNumber	5	loan
CY2023Q4	us-gaap	Mortgage Loans In Process Of Foreclosure Amount MortgageLoansInProcessOfForeclosureAmount	400000	usd
CY2022Q4	fnlc	Mortgage Loansin Processof Foreclosure Number MortgageLoansinProcessofForeclosureNumber	2	loan
CY2022Q4	us-gaap	Mortgage Loans In Process Of Foreclosure Amount MortgageLoansInProcessOfForeclosureAmount	166000	usd
CY2023Q4	fnlc	Financing Receivables Number Of Loan Classes FinancingReceivablesNumberOfLoanClasses	10	loan_class
CY2023Q4	fnlc	Commercial Real Estate Loans Maximum Loan To Value CommercialRealEstateLoansMaximumLoanToValue	0.80
CY2023Q4	fnlc	Construction Loans Actual Loan Portfolio To Company Capital ConstructionLoansActualLoanPortfolioToCompanyCapital	0.439
CY2023Q4	fnlc	Construction Loan Portfolio Maximum To Company Capital ConstructionLoanPortfolioMaximumToCompanyCapital	1.000
CY2023Q4	fnlc	Construction And Non Owner Occupied Commercial Real Estate Loans Portfolio To Company Capital ConstructionAndNonOwnerOccupiedCommercialRealEstateLoansPortfolioToCompanyCapital	2.194
CY2023Q4	fnlc	Construction And Non Owner Occupied Commercial Real Estate Loans Maximum Loan Portfolio To Company Capital ConstructionAndNonOwnerOccupiedCommercialRealEstateLoansMaximumLoanPortfolioToCompanyCapital	3.000
CY2023Q4	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	264000	usd
CY2022Q4	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	398000	usd
CY2023Q4	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	23766000	usd
CY2022Q4	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	16325000	usd
CY2023Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	24030000	usd
CY2022Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	16723000	usd
CY2023Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	24030000	usd
CY2022Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	16723000	usd
CY2023Q4	fnlc	Allowancefor Loan Lossesof Total Loans Percentage AllowanceforLoanLossesofTotalLoansPercentage	0.0113
CY2022Q4	fnlc	Allowancefor Loan Lossesof Total Loans Percentage AllowanceforLoanLossesofTotalLoansPercentage	0.0087
CY2022Q4	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	100000	usd
CY2023	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	-142000	usd
CY2023Q4	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	1255000	usd
CY2023Q4	fnlc	Financing Receivable Outstanding Loans And Commitments Subject By Independent Consulting Firm FinancingReceivableOutstandingLoansAndCommitmentsSubjectByIndependentConsultingFirm	0.60
CY2022Q4	fnlc	Commercial And Municipal Risk Rated Loans Receivable CommercialAndMunicipalRiskRatedLoansReceivable	1153225000	usd
CY2022Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	16723000	usd
CY2023	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Writeoff FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff	437000	usd
CY2023	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Recovery FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossRecovery	204000	usd
CY2022	us-gaap	Financing Receivable Excluding Accrued Interest Credit Loss Expense Reversal FinancingReceivableExcludingAccruedInterestCreditLossExpenseReversal	1750000	usd
CY2022Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	16723000	usd
CY2022Q4	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	398000	usd
CY2022Q4	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	16325000	usd
CY2022Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	1914674000	usd
CY2022Q4	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	6160000	usd
CY2022Q4	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	1908514000	usd
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	16253000	usd
CY2021	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Writeoff FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff	748000	usd
CY2021	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Recovery FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossRecovery	391000	usd
CY2021	us-gaap	Financing Receivable Excluding Accrued Interest Credit Loss Expense Reversal FinancingReceivableExcludingAccruedInterestCreditLossExpenseReversal	-375000	usd
CY2021Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	15521000	usd
CY2021Q4	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	576000	usd
CY2021Q4	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	14945000	usd
CY2021Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	1647649000	usd
CY2021Q4	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	12052000	usd
CY2021Q4	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	1635597000	usd
CY2023Q4	fnlc	Property Plant And Equipment And Operating Lease Right Of Use Asset Before Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndOperatingLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization	51620000	usd
CY2022Q4	fnlc	Property Plant And Equipment And Operating Lease Right Of Use Asset Before Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndOperatingLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization	50819000	usd
CY2023Q4	fnlc	Property Plant And Equipment And Operating Lease Right Of Use Asset Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndOperatingLeaseRightOfUseAssetAccumulatedDepreciationAndAmortization	22936000	usd
CY2022Q4	fnlc	Property Plant And Equipment And Operating Lease Right Of Use Asset Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndOperatingLeaseRightOfUseAssetAccumulatedDepreciationAndAmortization	22542000	usd
CY2023Q4	fnlc	Property Plant And Equipment And Operating Lease Right Of Use Asset Net Of Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndOperatingLeaseRightOfUseAssetNetOfAccumulatedDepreciationAndAmortization	28684000	usd
CY2022Q4	fnlc	Property Plant And Equipment And Operating Lease Right Of Use Asset Net Of Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndOperatingLeaseRightOfUseAssetNetOfAccumulatedDepreciationAndAmortization	28277000	usd
CY2023Q4	us-gaap	Finance Lease Liability Payments Due Next Twelve Months FinanceLeaseLiabilityPaymentsDueNextTwelveMonths	116000	usd
CY2023Q4	us-gaap	Finance Lease Liability Payments Due Year Two FinanceLeaseLiabilityPaymentsDueYearTwo	116000	usd
CY2023Q4	us-gaap	Finance Lease Liability Payments Due Year Three FinanceLeaseLiabilityPaymentsDueYearThree	116000	usd
CY2023Q4	us-gaap	Finance Lease Liability Payments Due Year Four FinanceLeaseLiabilityPaymentsDueYearFour	116000	usd
CY2023Q4	us-gaap	Finance Lease Liability Payments Due Year Five FinanceLeaseLiabilityPaymentsDueYearFive	4000	usd
CY2023Q4	us-gaap	Finance Lease Liability Payments Due After Year Five FinanceLeaseLiabilityPaymentsDueAfterYearFive	12000	usd
CY2023Q4	us-gaap	Finance Lease Liability Payments Due FinanceLeaseLiabilityPaymentsDue	480000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Remaining Lease Term LesseeOperatingLeaseRemainingLeaseTerm	P4Y
CY2023Q4	us-gaap	Lessee Operating Lease Discount Rate LesseeOperatingLeaseDiscountRate	0.0125
CY2023	fnlc	Lessee Operating Lease Discount Rate Input Term LesseeOperatingLeaseDiscountRateInputTerm	P5Y
CY2022Q4	us-gaap	Real Estate Owned Valuation Allowance RealEstateOwnedValuationAllowance	0	usd
CY2021Q4	us-gaap	Real Estate Owned Valuation Allowance RealEstateOwnedValuationAllowance	0	usd
CY2023Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	652000	usd
CY2022Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	737000	usd
CY2023Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	652000	usd
CY2022Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	737000	usd
CY2023	us-gaap	Lease Cost LeaseCost	97000	usd
CY2022	us-gaap	Lease Cost LeaseCost	97000	usd
CY2021	us-gaap	Lease Cost LeaseCost	34000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	97000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	97000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	91000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	28000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	28000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Payments Due After Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	403000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	744000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	92000	usd
CY2023Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	652000	usd
CY2023Q4	us-gaap	Real Estate Acquired Through Foreclosure RealEstateAcquiredThroughForeclosure	0	usd
CY2022Q4	us-gaap	Real Estate Acquired Through Foreclosure RealEstateAcquiredThroughForeclosure	0	usd
CY2022	us-gaap	Income Tax Reconciliation Nondeductible Expense Share Based Compensation Cost IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost	-54000	usd
CY2021	us-gaap	Income Tax Reconciliation Nondeductible Expense Share Based Compensation Cost IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost	-41000	usd
CY2023	us-gaap	Income Tax Reconciliation Tax Credits IncomeTaxReconciliationTaxCredits	201000	usd
CY2022	us-gaap	Income Tax Reconciliation Tax Credits IncomeTaxReconciliationTaxCredits	203000	usd
CY2021	us-gaap	Income Tax Reconciliation Tax Credits IncomeTaxReconciliationTaxCredits	150000	usd
CY2023	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	-26000	usd
CY2022	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	-25000	usd
CY2020Q4	us-gaap	Real Estate Owned Valuation Allowance RealEstateOwnedValuationAllowance	45000	usd
CY2023	us-gaap	Real Estate Owned Valuation Allowance Amounts Applied RealEstateOwnedValuationAllowanceAmountsApplied	0	usd
CY2022	us-gaap	Real Estate Owned Valuation Allowance Amounts Applied RealEstateOwnedValuationAllowanceAmountsApplied	0	usd
CY2021	us-gaap	Real Estate Owned Valuation Allowance Amounts Applied RealEstateOwnedValuationAllowanceAmountsApplied	45000	usd
CY2023	us-gaap	Real Estate Owned Valuation Allowance Provision1 RealEstateOwnedValuationAllowanceProvision1	0	usd
CY2022	us-gaap	Real Estate Owned Valuation Allowance Provision1 RealEstateOwnedValuationAllowanceProvision1	0	usd
CY2021	us-gaap	Real Estate Owned Valuation Allowance Provision1 RealEstateOwnedValuationAllowanceProvision1	0	usd
CY2023Q4	us-gaap	Real Estate Owned Valuation Allowance RealEstateOwnedValuationAllowance	0	usd
CY2022Q4	us-gaap	Real Estate Owned Valuation Allowance RealEstateOwnedValuationAllowance	0	usd
CY2021Q4	us-gaap	Real Estate Owned Valuation Allowance RealEstateOwnedValuationAllowance	0	usd
CY2023	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	7011000	usd
CY2022	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	7912000	usd
CY2021	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	6058000	usd
CY2023	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-1360000	usd
CY2022	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-127000	usd
CY2021	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	999000	usd
CY2023	us-gaap	Federal Income Tax Expense Benefit Continuing Operations FederalIncomeTaxExpenseBenefitContinuingOperations	5651000	usd
CY2022	us-gaap	Federal Income Tax Expense Benefit Continuing Operations FederalIncomeTaxExpenseBenefitContinuingOperations	7785000	usd
CY2021	us-gaap	Federal Income Tax Expense Benefit Continuing Operations FederalIncomeTaxExpenseBenefitContinuingOperations	7057000	usd
CY2023	us-gaap	State And Local Income Tax Expense Benefit Continuing Operations StateAndLocalIncomeTaxExpenseBenefitContinuingOperations	533000	usd
CY2022	us-gaap	State And Local Income Tax Expense Benefit Continuing Operations StateAndLocalIncomeTaxExpenseBenefitContinuingOperations	611000	usd
CY2021	us-gaap	State And Local Income Tax Expense Benefit Continuing Operations StateAndLocalIncomeTaxExpenseBenefitContinuingOperations	587000	usd
CY2023	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	6184000	usd
CY2022	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	8396000	usd
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	7644000	usd
CY2023	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	7498000	usd
CY2022	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	9951000	usd
CY2021	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	9222000	usd
CY2023	us-gaap	Income Tax Reconciliation Tax Exempt Income IncomeTaxReconciliationTaxExemptIncome	1481000	usd
CY2022	us-gaap	Income Tax Reconciliation Tax Exempt Income IncomeTaxReconciliationTaxExemptIncome	1756000	usd
CY2021	us-gaap	Income Tax Reconciliation Tax Exempt Income IncomeTaxReconciliationTaxExemptIncome	1833000	usd
CY2023	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	421000	usd
CY2022	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	483000	usd
CY2021	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	444000	usd
CY2023	us-gaap	Income Tax Reconciliation Nondeductible Expense Share Based Compensation Cost IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost	-27000	usd
CY2021	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	2000	usd
CY2023	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	6184000	usd
CY2022	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	8396000	usd
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	7644000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Provision For Loan Losses DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsProvisionForLoanLosses	5380000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Provision For Loan Losses DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsProvisionForLoanLosses	3512000	usd
CY2023Q4	fnlc	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Postretirement Benefits And Pension DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsPostretirementBenefitsAndPension	752000	usd
CY2022Q4	fnlc	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Postretirement Benefits And Pension DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsPostretirementBenefitsAndPension	828000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Unrealized Losses On Availablefor Sale Securities Gross DeferredTaxAssetsUnrealizedLossesOnAvailableforSaleSecuritiesGross	10520000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Unrealized Losses On Availablefor Sale Securities Gross DeferredTaxAssetsUnrealizedLossesOnAvailableforSaleSecuritiesGross	11887000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Derivative Instruments DeferredTaxAssetsDerivativeInstruments	913000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Derivative Instruments DeferredTaxAssetsDerivativeInstruments	1031000	usd
CY2023Q4	fnlc	Deferred Tax Assets Securities Transferred From Afs To Htm DeferredTaxAssetsSecuritiesTransferredFromAFSToHTM	15000	usd
CY2022Q4	fnlc	Deferred Tax Assets Securities Transferred From Afs To Htm DeferredTaxAssetsSecuritiesTransferredFromAFSToHTM	17000	usd
CY2023Q4	fnlc	Deferred Tax Assets Restricted Stock Grants DeferredTaxAssetsRestrictedStockGrants	323000	usd
CY2022Q4	fnlc	Deferred Tax Assets Restricted Stock Grants DeferredTaxAssetsRestrictedStockGrants	320000	usd
CY2023Q4	fnlc	Deferred Tax Assets Intangible Liabilities DeferredTaxAssetsIntangibleLiabilities	29000	usd
CY2022Q4	fnlc	Deferred Tax Assets Intangible Liabilities DeferredTaxAssetsIntangibleLiabilities	34000	usd
CY2023Q4	fnlc	Deferred Tax Assets Investmentin Limited Partnership DeferredTaxAssetsInvestmentinLimitedPartnership	99000	usd
CY2022Q4	fnlc	Deferred Tax Assets Investmentin Limited Partnership DeferredTaxAssetsInvestmentinLimitedPartnership	87000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	24000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	41000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	18055000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	17757000	usd
CY2023Q4	us-gaap	Deferred Tax Liabilities Financing Arrangements DeferredTaxLiabilitiesFinancingArrangements	2599000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Financing Arrangements DeferredTaxLiabilitiesFinancingArrangements	2285000	usd
CY2023Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	2383000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	2272000	usd
CY2023Q4	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets Goodwill DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsGoodwill	319000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets Goodwill DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsGoodwill	267000	usd
CY2023Q4	us-gaap	Deferred Tax Liabilities Mortgage Servicing Rights DeferredTaxLiabilitiesMortgageServicingRights	457000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Mortgage Servicing Rights DeferredTaxLiabilitiesMortgageServicingRights	524000	usd
CY2023Q4	us-gaap	Deferred Tax Liabilities Derivatives DeferredTaxLiabilitiesDerivatives	993000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Derivatives DeferredTaxLiabilitiesDerivatives	1176000	usd
CY2023Q4	us-gaap	Deferred Tax Liabilities Prepaid Expenses DeferredTaxLiabilitiesPrepaidExpenses	276000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Prepaid Expenses DeferredTaxLiabilitiesPrepaidExpenses	252000	usd
CY2023Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	7027000	usd
CY2022Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	6776000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	11028000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	10981000	usd
CY2023Q4	fnlc	Limited Partnerships Held As Investments LimitedPartnershipsHeldAsInvestments	4	limited_partnership
CY2022Q4	fnlc	Limited Partnerships Held As Investments LimitedPartnershipsHeldAsInvestments	4	limited_partnership
CY2023	us-gaap	Income Tax Reconciliation Tax Credits Investment IncomeTaxReconciliationTaxCreditsInvestment	350000	usd
CY2022	us-gaap	Income Tax Reconciliation Tax Credits Investment IncomeTaxReconciliationTaxCreditsInvestment	354000	usd
CY2023	us-gaap	Income Tax Reconciliation Nondeductible Expense Amortization IncomeTaxReconciliationNondeductibleExpenseAmortization	303000	usd
CY2022	us-gaap	Income Tax Reconciliation Nondeductible Expense Amortization IncomeTaxReconciliationNondeductibleExpenseAmortization	305000	usd
CY2023Q4	us-gaap	Limited Partners Capital Account LimitedPartnersCapitalAccount	1145000	usd
CY2022Q4	us-gaap	Limited Partners Capital Account LimitedPartnersCapitalAccount	1448000	usd
CY2023Q4	us-gaap	Time Deposits Less Than100000 TimeDepositsLessThan100000	646818000	usd
CY2022Q4	us-gaap	Time Deposits Less Than100000 TimeDepositsLessThan100000	489793000	usd
CY2023Q4	fnlc	Time Deposits Greater Than100000 And Less Than250000 TimeDepositsGreaterThan100000AndLessThan250000	251192000	usd
CY2022Q4	fnlc	Time Deposits Greater Than100000 And Less Than250000 TimeDepositsGreaterThan100000AndLessThan250000	259614000	usd
CY2023Q4	fnlc	Time Deposits250000 Or More TimeDeposits250000OrMore	172237000	usd
CY2022Q4	fnlc	Time Deposits250000 Or More TimeDeposits250000OrMore	118264000	usd
CY2023Q4	us-gaap	Time Deposits TimeDeposits	1070247000	usd
CY2022Q4	us-gaap	Time Deposits TimeDeposits	867671000	usd
CY2023Q4	us-gaap	Time Deposit Maturities Year One TimeDepositMaturitiesYearOne	689615000	usd
CY2023Q4	us-gaap	Time Deposit Maturities Year Two TimeDepositMaturitiesYearTwo	178110000	usd
CY2023Q4	us-gaap	Time Deposit Maturities Year Three TimeDepositMaturitiesYearThree	144253000	usd
CY2023Q4	us-gaap	Time Deposit Maturities Year Four TimeDepositMaturitiesYearFour	15354000	usd
CY2023Q4	us-gaap	Time Deposit Maturities Year Five TimeDepositMaturitiesYearFive	42844000	usd
CY2023Q4	us-gaap	Time Deposit Maturities After Year Five TimeDepositMaturitiesAfterYearFive	71000	usd
CY2023Q4	us-gaap	Time Deposits TimeDeposits	1070247000	usd
CY2023Q4	fnlc	Line Of Credit With Correspondent Banks LineOfCreditWithCorrespondentBanks	76000000	usd
CY2023Q4	fnlc	Credit Facility With Federal Reserve Bank Of Boston CreditFacilityWithFederalReserveBankOfBoston	224000000	usd
CY2023Q4	fnlc	Line Of Credit With Correspondent Banks And Credit Facility With Federal Reserve Of Boston LineOfCreditWithCorrespondentBanksAndCreditFacilityWithFederalReserveOfBoston	0	usd
CY2023Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due Within One Year Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueWithinOneYearOfBalanceSheetDate	20076000	usd
CY2023	fnlc	Federal Home Loan Bank Advances Interest Rate Maturities Summary Duein Year Two FederalHomeLoanBankAdvancesInterestRateMaturitiesSummaryDueinYearTwo	0
CY2023Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due From One To Two Years Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueFromOneToTwoYearsOfBalanceSheetDate	0	usd
CY2023	fnlc	Federal Home Loan Bank Advances Interest Rate Maturities Summary Duein Year Three FederalHomeLoanBankAdvancesInterestRateMaturitiesSummaryDueinYearThree	0
CY2023Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due From Two To Three Years Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueFromTwoToThreeYearsOfBalanceSheetDate	0	usd
CY2023	fnlc	Federal Home Loan Bank Advances Interest Rate Maturities Summary Duein Year Four FederalHomeLoanBankAdvancesInterestRateMaturitiesSummaryDueinYearFour	0
CY2023Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due From Three To Four Years Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueFromThreeToFourYearsOfBalanceSheetDate	0	usd
CY2023	fnlc	Federal Home Loan Bank Advances Interest Rate Maturities Summary Due In Year Five And Thereafter FederalHomeLoanBankAdvancesInterestRateMaturitiesSummaryDueInYearFiveAndThereafter	0.0000
CY2023Q4	fnlc	Federal Home Loan Bank Advance Maturity Year Five And Thereafter FederalHomeLoanBankAdvanceMaturityYearFiveAndThereafter	0	usd
CY2023Q4	us-gaap	Advances From Federal Home Loan Banks AdvancesFromFederalHomeLoanBanks	20076000	usd
CY2023Q4	us-gaap	Securities Sold Under Agreements To Repurchase SecuritiesSoldUnderAgreementsToRepurchase	49576000	usd
CY2023Q4	fnlc	Total Federal Home Loan Bank Advances Treasury Tax Notes And Repurchase Agreements TotalFederalHomeLoanBankAdvancesTreasuryTaxNotesAndRepurchaseAgreements	69652000	usd
CY2022Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due Within One Year Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueWithinOneYearOfBalanceSheetDate	38990000	usd
CY2022	fnlc	Federal Home Loan Bank Advances Interest Rate Maturities Summary Duein Year Two FederalHomeLoanBankAdvancesInterestRateMaturitiesSummaryDueinYearTwo	0
CY2022Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due From One To Two Years Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueFromOneToTwoYearsOfBalanceSheetDate	84000	usd
CY2022	fnlc	Federal Home Loan Bank Advances Interest Rate Maturities Summary Duein Year Three FederalHomeLoanBankAdvancesInterestRateMaturitiesSummaryDueinYearThree	0
CY2022Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due From Two To Three Years Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueFromTwoToThreeYearsOfBalanceSheetDate	0	usd
CY2022	fnlc	Federal Home Loan Bank Advances Interest Rate Maturities Summary Duein Year Four FederalHomeLoanBankAdvancesInterestRateMaturitiesSummaryDueinYearFour	0
CY2022Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due From Three To Four Years Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueFromThreeToFourYearsOfBalanceSheetDate	0	usd
CY2022	fnlc	Federal Home Loan Bank Advances Interest Rate Maturities Summary Due In Year Five And Thereafter FederalHomeLoanBankAdvancesInterestRateMaturitiesSummaryDueInYearFiveAndThereafter	0
CY2022Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due From Four To Five Years Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueFromFourToFiveYearsOfBalanceSheetDate	0	usd
CY2022Q4	us-gaap	Advances From Federal Home Loan Banks AdvancesFromFederalHomeLoanBanks	39074000	usd
CY2022Q4	us-gaap	Securities Sold Under Agreements To Repurchase SecuritiesSoldUnderAgreementsToRepurchase	64409000	usd
CY2022Q4	fnlc	Total Federal Home Loan Bank Advances Treasury Tax Notes And Repurchase Agreements TotalFederalHomeLoanBankAdvancesTreasuryTaxNotesAndRepurchaseAgreements	103483000	usd
CY2023	us-gaap	Deferred Compensation Arrangement With Individual Requisite Service Period1 DeferredCompensationArrangementWithIndividualRequisiteServicePeriod1	P3M
CY2023Q4	fnlc	Defined Contribution Plan Employer Maximum Percentage Match Of Employee Annual Salary DefinedContributionPlanEmployerMaximumPercentageMatchOfEmployeeAnnualSalary	0.030
CY2023	us-gaap	Defined Contribution Plan Employer Matching Contribution Percent Of Match DefinedContributionPlanEmployerMatchingContributionPercentOfMatch	0.030
CY2023	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	1067000	usd
CY2022	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	977000	usd
CY2021	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	775000	usd
CY2023	fnlc	Post Employment Plan Supplemental Benefits Payment Period Upon Retirement Or Death PostEmploymentPlanSupplementalBenefitsPaymentPeriodUponRetirementOrDeath	P20Y
CY2023	us-gaap	Pension And Other Postretirement Benefit Expense PensionAndOtherPostretirementBenefitExpense	57000	usd
CY2022	us-gaap	Pension And Other Postretirement Benefit Expense PensionAndOtherPostretirementBenefitExpense	308000	usd
CY2021	us-gaap	Pension And Other Postretirement Benefit Expense PensionAndOtherPostretirementBenefitExpense	167000	usd
CY2023Q4	us-gaap	Defined Benefit Pension Plan Current And Noncurrent Liabilities DefinedBenefitPensionPlanCurrentAndNoncurrentLiabilities	2664000	usd
CY2022Q4	us-gaap	Defined Benefit Pension Plan Current And Noncurrent Liabilities DefinedBenefitPensionPlanCurrentAndNoncurrentLiabilities	2893000	usd
CY2023Q4	fnlc	Number Of Post Retirement Benefit Plans NumberOfPostRetirementBenefitPlans	2	postretirement_benefit_plan
CY2023Q4	fnlc	Post Retirement Benefit Plan Health Insurance Subsidy Range Minimum PostRetirementBenefitPlanHealthInsuranceSubsidyRangeMinimum	40	usd
CY2023Q4	fnlc	Post Retirement Benefit Plan Health Insurance Subsidy Range Maximum PostRetirementBenefitPlanHealthInsuranceSubsidyRangeMaximum	1200	usd
CY2022	us-gaap	Defined Benefit Plan Amortization Of Gains Losses DefinedBenefitPlanAmortizationOfGainsLosses	0	usd
CY2021	us-gaap	Defined Benefit Plan Amortization Of Gains Losses DefinedBenefitPlanAmortizationOfGainsLosses	0	usd
CY2022Q4	us-gaap	Defined Benefit Plan Benefit Obligation DefinedBenefitPlanBenefitObligation	1050000	usd
CY2021Q4	us-gaap	Defined Benefit Plan Benefit Obligation DefinedBenefitPlanBenefitObligation	1353000	usd
CY2020Q4	us-gaap	Defined Benefit Plan Benefit Obligation DefinedBenefitPlanBenefitObligation	1523000	usd
CY2023	fnlc	Defined Benefit Plan Net Periodic Benefit Cost Credit Interest Cost Statement Of Income Or Comprehensive Income Extensible List Not Disclosed Flag DefinedBenefitPlanNetPeriodicBenefitCostCreditInterestCostStatementOfIncomeOrComprehensiveIncomeExtensibleListNotDisclosedFlag	Interest cost
CY2023	us-gaap	Defined Benefit Plan Interest Cost DefinedBenefitPlanInterestCost	48000	usd
CY2022	us-gaap	Defined Benefit Plan Interest Cost DefinedBenefitPlanInterestCost	33000	usd
CY2021	us-gaap	Defined Benefit Plan Interest Cost DefinedBenefitPlanInterestCost	29000	usd
CY2023	us-gaap	Defined Benefit Plan Benefit Obligation Benefits Paid DefinedBenefitPlanBenefitObligationBenefitsPaid	79000	usd
CY2022	us-gaap	Defined Benefit Plan Benefit Obligation Benefits Paid DefinedBenefitPlanBenefitObligationBenefitsPaid	93000	usd
CY2021	us-gaap	Defined Benefit Plan Benefit Obligation Benefits Paid DefinedBenefitPlanBenefitObligationBenefitsPaid	93000	usd
CY2023Q4	fnlc	Actuarialgainloss Actuarialgainloss	-100000	usd
CY2022Q4	fnlc	Actuarialgainloss Actuarialgainloss	-243000	usd
CY2021Q4	fnlc	Actuarialgainloss Actuarialgainloss	-106000	usd
CY2023Q4	us-gaap	Defined Benefit Plan Benefit Obligation DefinedBenefitPlanBenefitObligation	919000	usd
CY2022Q4	us-gaap	Defined Benefit Plan Benefit Obligation DefinedBenefitPlanBenefitObligation	1050000	usd
CY2021Q4	us-gaap	Defined Benefit Plan Benefit Obligation DefinedBenefitPlanBenefitObligation	1353000	usd
CY2023Q4	us-gaap	Defined Benefit Plan Benefit Obligation DefinedBenefitPlanBenefitObligation	919000	usd
CY2022Q4	us-gaap	Defined Benefit Plan Benefit Obligation DefinedBenefitPlanBenefitObligation	1050000	usd
CY2021Q4	us-gaap	Defined Benefit Plan Benefit Obligation DefinedBenefitPlanBenefitObligation	1353000	usd
CY2023	us-gaap	Defined Benefit Plan Actuarial Gain Loss DefinedBenefitPlanActuarialGainLoss	384000	usd
CY2022	us-gaap	Defined Benefit Plan Actuarial Gain Loss DefinedBenefitPlanActuarialGainLoss	345000	usd
CY2021	us-gaap	Defined Benefit Plan Actuarial Gain Loss DefinedBenefitPlanActuarialGainLoss	133000	usd
CY2023Q4	us-gaap	Defined Benefit Plan Funded Status Of Plan DefinedBenefitPlanFundedStatusOfPlan	-1303000	usd
CY2022Q4	us-gaap	Defined Benefit Plan Funded Status Of Plan DefinedBenefitPlanFundedStatusOfPlan	-1395000	usd
CY2021Q4	us-gaap	Defined Benefit Plan Funded Status Of Plan DefinedBenefitPlanFundedStatusOfPlan	-1486000	usd
CY2023Q4	fnlc	Weighted Average Discount Rate As Of December31 WeightedAverageDiscountRateAsOfDecember31	0.0467
CY2022Q4	fnlc	Weighted Average Discount Rate As Of December31 WeightedAverageDiscountRateAsOfDecember31	0.0475
CY2021Q4	fnlc	Weighted Average Discount Rate As Of December31 WeightedAverageDiscountRateAsOfDecember31	0.0250
CY2023	us-gaap	Defined Benefit Plan Interest Cost DefinedBenefitPlanInterestCost	48000	usd
CY2022	us-gaap	Defined Benefit Plan Interest Cost DefinedBenefitPlanInterestCost	33000	usd
CY2021	us-gaap	Defined Benefit Plan Interest Cost DefinedBenefitPlanInterestCost	29000	usd
CY2023	fnlc	Defined Benefit Plan Net Periodic Benefit Cost Credit Amortization Of Gain Loss Statement Of Income Or Comprehensive Income Extensible List Not Disclosed Flag DefinedBenefitPlanNetPeriodicBenefitCostCreditAmortizationOfGainLossStatementOfIncomeOrComprehensiveIncomeExtensibleListNotDisclosedFlag	Amortization of gains
CY2023	us-gaap	Defined Benefit Plan Amortization Of Gains Losses DefinedBenefitPlanAmortizationOfGainsLosses	29000	usd
CY2021	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	36269000	usd
CY2023	fnlc	Defined Benefit Plan Other Settlement Expense DefinedBenefitPlanOtherSettlementExpense	33000	usd
CY2022	fnlc	Defined Benefit Plan Other Settlement Expense DefinedBenefitPlanOtherSettlementExpense	31000	usd
CY2021	fnlc	Defined Benefit Plan Other Settlement Expense DefinedBenefitPlanOtherSettlementExpense	9000	usd
CY2023	us-gaap	Defined Benefit Plan Net Periodic Benefit Cost DefinedBenefitPlanNetPeriodicBenefitCost	-14000	usd
CY2022	us-gaap	Defined Benefit Plan Net Periodic Benefit Cost DefinedBenefitPlanNetPeriodicBenefitCost	2000	usd
CY2021	us-gaap	Defined Benefit Plan Net Periodic Benefit Cost DefinedBenefitPlanNetPeriodicBenefitCost	20000	usd
CY2023	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Discount Rate DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate	0.0475
CY2022	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Discount Rate DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate	0.0250
CY2021	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Discount Rate DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate	0.0200
CY2023Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Next Twelve Months DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths	84000	usd
CY2023Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Year Two DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo	83000	usd
CY2023Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Year Three DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree	82000	usd
CY2023Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Year Four DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour	80000	usd
CY2023Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Year Five DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive	78000	usd
CY2023Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Five Fiscal Years Thereafter DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter	338000	usd
CY2023Q4	us-gaap	Defined Benefit Plan Expected Future Employer Contributions Remainder Of Fiscal Year DefinedBenefitPlanExpectedFutureEmployerContributionsRemainderOfFiscalYear	0	usd
CY2023Q4	us-gaap	Defined Benefit Plan Accumulated Other Comprehensive Income Net Gains Losses Before Tax DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax	384000	usd
CY2022Q4	us-gaap	Defined Benefit Plan Accumulated Other Comprehensive Income Net Gains Losses Before Tax DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax	345000	usd
CY2023Q4	us-gaap	Defined Benefit Plan Expected Amortization Of Gain Loss Next Fiscal Year DefinedBenefitPlanExpectedAmortizationOfGainLossNextFiscalYear	0	usd
CY2023Q4	fnlc	Accumulated Other Comprehensive Income Defined Benefit Plans Tax Deferred Tax Benefit AccumulatedOtherComprehensiveIncomeDefinedBenefitPlansTaxDeferredTaxBenefit	-81000	usd
CY2022Q4	fnlc	Accumulated Other Comprehensive Income Defined Benefit Plans Tax Deferred Tax Benefit AccumulatedOtherComprehensiveIncomeDefinedBenefitPlansTaxDeferredTaxBenefit	-72000	usd
CY2023	fnlc	Defined Benefit Plan Future Deferred Tax Benefit DefinedBenefitPlanFutureDeferredTaxBenefit	0	usd
CY2023Q4	us-gaap	Accumulated Other Comprehensive Income Loss Defined Benefit Pension And Other Postretirement Plans Net Of Tax AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax	-303000	usd
CY2022Q4	us-gaap	Accumulated Other Comprehensive Income Loss Defined Benefit Pension And Other Postretirement Plans Net Of Tax AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax	-273000	usd
CY2023Q4	us-gaap	Defined Benefit Plan Expected Amortization Next Fiscal Year DefinedBenefitPlanExpectedAmortizationNextFiscalYear	0	usd
CY2016Q4	fnlc	Number Of Shares Available For Grant Under Employee Savings And Investment Plan NumberOfSharesAvailableForGrantUnderEmployeeSavingsAndInvestmentPlan	250000	shares
CY2023Q4	fnlc	Number Of Shares Issued Under Employee Savings And Investment Plan NumberOfSharesIssuedUnderEmployeeSavingsAndInvestmentPlan	111665	shares
CY2023Q4	fnlc	Number Of Shares Available For Future Use Under Employee Savings And Investment Plan NumberOfSharesAvailableForFutureUseUnderEmployeeSavingsAndInvestmentPlan	138335	shares
CY2015Q4	fnlc	Number Of Shares Available For Grant Under Employee Savings And Investment Plan NumberOfSharesAvailableForGrantUnderEmployeeSavingsAndInvestmentPlan	700000	shares
CY2023	us-gaap	Stock Issued During Period Shares Employee Stock Purchase Plans StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans	17472	shares
CY2022	us-gaap	Stock Issued During Period Shares Employee Stock Purchase Plans StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans	14990	shares
CY2021	us-gaap	Stock Issued During Period Shares Employee Stock Purchase Plans StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans	12267	shares
CY2001Q4	fnlc	Number Of Shares Registered Pursuant To Dividend Reinvestment Plan NumberOfSharesRegisteredPursuantToDividendReinvestmentPlan	600000	shares
	us-gaap	Stock Issued During Period Shares Dividend Reinvestment Plan StockIssuedDuringPeriodSharesDividendReinvestmentPlan	331106	shares
CY2023	fnlc	Stock Remainingunder Plan Shares Dividend Reinvestment Plan StockRemainingunderPlanSharesDividendReinvestmentPlan	268894	shares
CY2023	us-gaap	Stock Issued During Period Shares Dividend Reinvestment Plan StockIssuedDuringPeriodSharesDividendReinvestmentPlan	14418	shares
CY2022	us-gaap	Stock Issued During Period Shares Dividend Reinvestment Plan StockIssuedDuringPeriodSharesDividendReinvestmentPlan	11326	shares
CY2021	us-gaap	Stock Issued During Period Shares Dividend Reinvestment Plan StockIssuedDuringPeriodSharesDividendReinvestmentPlan	11772	shares
CY2023	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	2394000	usd
CY2023	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	820000	usd
CY2023Q4	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized	856000	usd
CY2022	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	809000	usd
CY2022Q4	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized	796000	usd
CY2023	us-gaap	Net Income Loss NetIncomeLoss	29518000	usd
CY2023	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	29518000	usd
CY2023	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	10998041	shares
CY2023	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.68
CY2023	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	83847	shares
CY2023	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	29518000	usd
CY2023	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	11081888	shares
CY2023	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.66
CY2022	us-gaap	Net Income Loss NetIncomeLoss	38990000	usd
CY2022	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	38990000	usd
CY2022	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	10931328	shares
CY2022	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	3.56
CY2022	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	99330	shares
CY2022	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	38990000	usd
CY2022	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	11030658	shares
CY2022	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	3.53
CY2021	us-gaap	Net Income Loss NetIncomeLoss	36269000	usd
CY2021	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	10903844	shares
CY2021	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	3.33
CY2021	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	83335	shares
CY2021	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	36269000	usd
CY2021	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	10987179	shares
CY2021	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	3.30
CY2022Q4	fnlc	Retained Earnings From Prior Two Years Available For Dividends RetainedEarningsFromPriorTwoYearsAvailableForDividends	41545000	usd
CY2023Q4	fnlc	Retained Earnings From Prior Two Years Available For Dividends RetainedEarningsFromPriorTwoYearsAvailableForDividends	41545000	usd
CY2023Q4	fnlc	Capital Conservation Buffer CapitalConservationBuffer	0.0566
CY2023Q4	fnlc	Capital Conservation Buffer Phasein Minimum CapitalConservationBufferPhaseinMinimum	0.025
CY2023Q4	us-gaap	Fair Value Disclosure Offbalance Sheet Risks Amount Liability FairValueDisclosureOffbalanceSheetRisksAmountLiability	320440000	usd
CY2022Q4	us-gaap	Fair Value Disclosure Offbalance Sheet Risks Amount Liability FairValueDisclosureOffbalanceSheetRisksAmountLiability	324383000	usd
CY2023	us-gaap	Servicing Asset At Amortized Cost Other Than Temporary Impairments ServicingAssetAtAmortizedCostOtherThanTemporaryImpairments	0	usd
CY2022	us-gaap	Servicing Asset At Amortized Cost Other Than Temporary Impairments ServicingAssetAtAmortizedCostOtherThanTemporaryImpairments	0	usd
CY2023Q4	us-gaap	Real Estate Owned Valuation Allowance RealEstateOwnedValuationAllowance	0	usd
CY2022Q4	us-gaap	Real Estate Owned Valuation Allowance RealEstateOwnedValuationAllowance	0	usd
CY2023Q4	fnlc	Impaired Financing Receivable Related Allowance Measuredat Fair Value ImpairedFinancingReceivableRelatedAllowanceMeasuredatFairValue	19000	usd
CY2022Q4	fnlc	Impaired Financing Receivable Related Allowance Measuredat Fair Value ImpairedFinancingReceivableRelatedAllowanceMeasuredatFairValue	135000	usd
CY2023Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	29894000	usd
CY2023Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	31942000	usd
CY2022Q1	us-gaap	Interest Bearing Deposits In Banks InterestBearingDepositsInBanks	18427000	usd
CY2022Q2	us-gaap	Interest Bearing Deposits In Banks InterestBearingDepositsInBanks	22871000	usd
CY2022Q3	us-gaap	Interest Bearing Deposits In Banks InterestBearingDepositsInBanks	65786000	usd
CY2022Q4	us-gaap	Interest Bearing Deposits In Banks InterestBearingDepositsInBanks	3693000	usd
CY2023Q1	us-gaap	Interest Bearing Deposits In Banks InterestBearingDepositsInBanks	2773000	usd
CY2023Q2	us-gaap	Interest Bearing Deposits In Banks InterestBearingDepositsInBanks	3978000	usd
CY2023Q3	us-gaap	Interest Bearing Deposits In Banks InterestBearingDepositsInBanks	38366000	usd
CY2023Q4	us-gaap	Interest Bearing Deposits In Banks InterestBearingDepositsInBanks	3488000	usd
CY2023	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	1187000	usd
CY2022	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	1296000	usd
CY2021	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	1181000	usd
CY2023Q4	fnlc	Atm And Interchange Expense AtmAndInterchangeExpense	1714000	usd
CY2022Q4	fnlc	Atm And Interchange Expense AtmAndInterchangeExpense	1568000	usd
CY2021Q4	fnlc	Atm And Interchange Expense AtmAndInterchangeExpense	1446000	usd
CY2023Q4	fnlc	Other Loan Expenses OtherLoanExpenses	5000	usd
CY2022Q4	fnlc	Other Loan Expenses OtherLoanExpenses	627000	usd
CY2021Q4	fnlc	Other Loan Expenses OtherLoanExpenses	2198000	usd
CY2023	us-gaap	Loss Contingency Disclosures LossContingencyDisclosures	Legal Contingencies<div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Various legal claims also arise from time to time in the normal course of business which, in the opinion of Management, will have no material effect on the Company's consolidated financial statements.</span></div>
CY2023	us-gaap	Prior Period Reclassification Adjustment Description PriorPeriodReclassificationAdjustmentDescription	Reclassifications<div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Certain items from prior years were reclassified in the financial statements to conform with the current year presentation. These do not have a material impact on the balance sheet or statement of income presentations.</span></div>
CY2023Q1	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	1397000	usd
CY2022Q1	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	22051000	usd
CY2022Q2	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	23453000	usd
CY2022Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	27408000	usd
CY2022Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	22728000	usd
CY2023Q1	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	27458000	usd
CY2023Q2	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	25077000	usd
CY2022Q1	us-gaap	Investments Investments	690198000	usd
CY2022Q2	us-gaap	Investments Investments	681430000	usd
CY2022Q3	us-gaap	Investments Investments	665174000	usd
CY2022Q4	us-gaap	Investments Investments	678405000	usd
CY2023Q1	us-gaap	Investments Investments	680087000	usd
CY2023Q2	us-gaap	Investments Investments	668342000	usd
CY2023Q3	us-gaap	Investments Investments	672346000	usd
CY2023Q4	us-gaap	Investments Investments	667288000	usd
CY2022Q1	fnlc	Federal Home Loan Bank And Federal Reserve Bank Stock At Cost FederalHomeLoanBankAndFederalReserveBankStockAtCost	5402000	usd
CY2022Q2	fnlc	Federal Home Loan Bank And Federal Reserve Bank Stock At Cost FederalHomeLoanBankAndFederalReserveBankStockAtCost	4720000	usd
CY2022Q3	fnlc	Federal Home Loan Bank And Federal Reserve Bank Stock At Cost FederalHomeLoanBankAndFederalReserveBankStockAtCost	4514000	usd
CY2022Q4	fnlc	Federal Home Loan Bank And Federal Reserve Bank Stock At Cost FederalHomeLoanBankAndFederalReserveBankStockAtCost	3883000	usd
CY2023Q1	fnlc	Federal Home Loan Bank And Federal Reserve Bank Stock At Cost FederalHomeLoanBankAndFederalReserveBankStockAtCost	3874000	usd
CY2023Q2	fnlc	Federal Home Loan Bank And Federal Reserve Bank Stock At Cost FederalHomeLoanBankAndFederalReserveBankStockAtCost	5227000	usd
CY2023Q3	fnlc	Federal Home Loan Bank And Federal Reserve Bank Stock At Cost FederalHomeLoanBankAndFederalReserveBankStockAtCost	3860000	usd
CY2023Q4	fnlc	Federal Home Loan Bank And Federal Reserve Bank Stock At Cost FederalHomeLoanBankAndFederalReserveBankStockAtCost	3385000	usd
CY2022Q1	fnlc	Loans And Lease Receivable Net LoansAndLeaseReceivableNet	1691982000	usd
CY2022Q2	fnlc	Loans And Lease Receivable Net LoansAndLeaseReceivableNet	1772843000	usd
CY2022Q3	fnlc	Loans And Lease Receivable Net LoansAndLeaseReceivableNet	1841588000	usd
CY2022Q4	fnlc	Loans And Lease Receivable Net LoansAndLeaseReceivableNet	1898226000	usd
CY2023Q1	fnlc	Loans And Lease Receivable Net LoansAndLeaseReceivableNet	1959389000	usd
CY2023Q2	fnlc	Loans And Lease Receivable Net LoansAndLeaseReceivableNet	2037488000	usd
CY2023Q3	fnlc	Loans And Lease Receivable Net LoansAndLeaseReceivableNet	2056806000	usd
CY2023Q4	fnlc	Loans And Lease Receivable Net LoansAndLeaseReceivableNet	2105424000	usd
CY2022Q1	us-gaap	Other Assets Miscellaneous OtherAssetsMiscellaneous	120547000	usd
CY2022Q2	us-gaap	Other Assets Miscellaneous OtherAssetsMiscellaneous	125037000	usd
CY2022Q3	us-gaap	Other Assets Miscellaneous OtherAssetsMiscellaneous	130595000	usd
CY2022Q4	us-gaap	Other Assets Miscellaneous OtherAssetsMiscellaneous	132243000	usd
CY2023Q1	us-gaap	Other Assets Miscellaneous OtherAssetsMiscellaneous	138239000	usd
CY2023Q2	us-gaap	Other Assets Miscellaneous OtherAssetsMiscellaneous	134703000	usd
CY2023Q3	us-gaap	Other Assets Miscellaneous OtherAssetsMiscellaneous	142867000	usd
CY2023Q4	us-gaap	Other Assets Miscellaneous OtherAssetsMiscellaneous	135171000	usd
CY2022Q1	us-gaap	Assets Assets	2548607000	usd
CY2022Q2	us-gaap	Assets Assets	2630354000	usd
CY2022Q3	us-gaap	Assets Assets	2735065000	usd
CY2022Q4	us-gaap	Assets Assets	2739178000	usd
CY2023Q1	us-gaap	Assets Assets	2811820000	usd
CY2023Q2	us-gaap	Assets Assets	2874815000	usd
CY2023Q3	us-gaap	Assets Assets	2944139000	usd
CY2023Q4	us-gaap	Assets Assets	2946698000	usd
CY2022Q1	us-gaap	Deposits Deposits	2158539000	usd
CY2022Q2	us-gaap	Deposits Deposits	2252022000	usd
CY2022Q3	us-gaap	Deposits Deposits	2369949000	usd
CY2022Q4	us-gaap	Deposits Deposits	2378877000	usd
CY2023Q1	us-gaap	Deposits Deposits	2466701000	usd
CY2023Q2	us-gaap	Deposits Deposits	2499862000	usd
CY2023Q3	us-gaap	Deposits Deposits	2599937000	usd
CY2023Q4	us-gaap	Deposits Deposits	2599662000	usd
CY2022Q1	fnlc	Total Federal Home Loan Bank Advances Treasury Tax Notes And Repurchase Agreements TotalFederalHomeLoanBankAdvancesTreasuryTaxNotesAndRepurchaseAgreements	133712000	usd
CY2022Q2	fnlc	Total Federal Home Loan Bank Advances Treasury Tax Notes And Repurchase Agreements TotalFederalHomeLoanBankAdvancesTreasuryTaxNotesAndRepurchaseAgreements	126588000	usd
CY2022Q3	fnlc	Total Federal Home Loan Bank Advances Treasury Tax Notes And Repurchase Agreements TotalFederalHomeLoanBankAdvancesTreasuryTaxNotesAndRepurchaseAgreements	118343000	usd
CY2022Q4	fnlc	Total Federal Home Loan Bank Advances Treasury Tax Notes And Repurchase Agreements TotalFederalHomeLoanBankAdvancesTreasuryTaxNotesAndRepurchaseAgreements	103483000	usd
CY2023Q1	fnlc	Total Federal Home Loan Bank Advances Treasury Tax Notes And Repurchase Agreements TotalFederalHomeLoanBankAdvancesTreasuryTaxNotesAndRepurchaseAgreements	83881000	usd
CY2023Q2	fnlc	Total Federal Home Loan Bank Advances Treasury Tax Notes And Repurchase Agreements TotalFederalHomeLoanBankAdvancesTreasuryTaxNotesAndRepurchaseAgreements	114481000	usd
CY2023Q3	fnlc	Total Federal Home Loan Bank Advances Treasury Tax Notes And Repurchase Agreements TotalFederalHomeLoanBankAdvancesTreasuryTaxNotesAndRepurchaseAgreements	82993000	usd
CY2023Q4	fnlc	Total Federal Home Loan Bank Advances Treasury Tax Notes And Repurchase Agreements TotalFederalHomeLoanBankAdvancesTreasuryTaxNotesAndRepurchaseAgreements	69652000	usd
CY2022Q1	us-gaap	Other Liabilities OtherLiabilities	22710000	usd
CY2022Q2	us-gaap	Other Liabilities OtherLiabilities	24059000	usd
CY2022Q3	us-gaap	Other Liabilities OtherLiabilities	26856000	usd
CY2022Q4	us-gaap	Other Liabilities OtherLiabilities	27895000	usd
CY2023Q1	us-gaap	Other Liabilities OtherLiabilities	32777000	usd
CY2023Q2	us-gaap	Other Liabilities OtherLiabilities	28469000	usd
CY2023Q3	us-gaap	Other Liabilities OtherLiabilities	34544000	usd
CY2023Q4	us-gaap	Other Liabilities OtherLiabilities	34305000	usd
CY2022Q1	us-gaap	Stockholders Equity StockholdersEquity	233646000	usd
CY2022Q2	us-gaap	Stockholders Equity StockholdersEquity	227685000	usd
CY2022Q3	us-gaap	Stockholders Equity StockholdersEquity	219917000	usd
CY2022Q4	us-gaap	Stockholders Equity StockholdersEquity	228923000	usd
CY2023Q1	us-gaap	Stockholders Equity StockholdersEquity	228461000	usd
CY2023Q2	us-gaap	Stockholders Equity StockholdersEquity	232003000	usd
CY2023Q3	us-gaap	Stockholders Equity StockholdersEquity	226665000	usd
CY2023Q4	us-gaap	Stockholders Equity StockholdersEquity	243079000	usd
CY2022Q1	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	2548607000	usd
CY2022Q2	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	2630354000	usd
CY2022Q3	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	2735065000	usd
CY2022Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	2739178000	usd
CY2023Q1	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	2811820000	usd
CY2023Q2	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	2874815000	usd
CY2023Q3	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	2944139000	usd
CY2023Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	2946698000	usd
CY2022Q1	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	20533000	usd
CY2022Q2	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	21431000	usd
CY2022Q3	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	23991000	usd
CY2022Q4	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	27080000	usd
CY2023Q1	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	28914000	usd
CY2023Q2	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	31184000	usd
CY2023Q3	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	33254000	usd
CY2023Q4	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	34822000	usd
CY2022Q1	us-gaap	Interest Expense InterestExpense	1913000	usd
CY2022Q2	us-gaap	Interest Expense InterestExpense	2733000	usd
CY2022Q3	us-gaap	Interest Expense InterestExpense	4627000	usd
CY2022Q4	us-gaap	Interest Expense InterestExpense	7596000	usd
CY2023Q1	us-gaap	Interest Expense InterestExpense	11439000	usd
CY2023Q2	us-gaap	Interest Expense InterestExpense	15259000	usd
CY2023Q3	us-gaap	Interest Expense InterestExpense	17300000	usd
CY2023Q4	us-gaap	Interest Expense InterestExpense	18969000	usd
CY2022Q1	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	18620000	usd
CY2022Q2	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	18698000	usd
CY2022Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	19364000	usd
CY2022Q4	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	19484000	usd
CY2023Q1	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	17475000	usd
CY2023Q2	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	15925000	usd
CY2023Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	15954000	usd
CY2023Q4	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	15853000	usd
CY2022Q1	fnlc	Credit Loss Expense Reversal CreditLossExpenseReversal	450000	usd
CY2022Q2	fnlc	Credit Loss Expense Reversal CreditLossExpenseReversal	450000	usd
CY2022Q3	fnlc	Credit Loss Expense Reversal CreditLossExpenseReversal	400000	usd
CY2022Q4	fnlc	Credit Loss Expense Reversal CreditLossExpenseReversal	450000	usd
CY2023Q1	fnlc	Credit Loss Expense Reversal CreditLossExpenseReversal	550000	usd
CY2023Q2	fnlc	Credit Loss Expense Reversal CreditLossExpenseReversal	151000	usd
CY2023Q3	fnlc	Credit Loss Expense Reversal CreditLossExpenseReversal	-200000	usd
CY2023Q4	fnlc	Credit Loss Expense Reversal CreditLossExpenseReversal	683000	usd
CY2022Q1	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	18170000	usd
CY2022Q2	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	18248000	usd
CY2022Q3	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	18964000	usd
CY2022Q4	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	19034000	usd
CY2023Q1	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	16925000	usd
CY2023Q2	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	15774000	usd
CY2023Q3	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	16154000	usd
CY2023Q4	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	15170000	usd
CY2022Q1	us-gaap	Noninterest Income NoninterestIncome	4232000	usd
CY2022Q2	us-gaap	Noninterest Income NoninterestIncome	4080000	usd
CY2022Q3	us-gaap	Noninterest Income NoninterestIncome	4715000	usd
CY2022Q4	us-gaap	Noninterest Income NoninterestIncome	3847000	usd
CY2023Q1	us-gaap	Noninterest Income NoninterestIncome	3569000	usd
CY2023Q2	us-gaap	Noninterest Income NoninterestIncome	3870000	usd
CY2023Q3	us-gaap	Noninterest Income NoninterestIncome	3891000	usd
CY2023Q4	us-gaap	Noninterest Income NoninterestIncome	4107000	usd
CY2022Q1	us-gaap	Noninterest Expense NoninterestExpense	10650000	usd
CY2022Q2	us-gaap	Noninterest Expense NoninterestExpense	10172000	usd
CY2022Q3	us-gaap	Noninterest Expense NoninterestExpense	11371000	usd
CY2022Q4	us-gaap	Noninterest Expense NoninterestExpense	11711000	usd
CY2023Q1	us-gaap	Noninterest Expense NoninterestExpense	10850000	usd
CY2023Q2	us-gaap	Noninterest Expense NoninterestExpense	10715000	usd
CY2023Q3	us-gaap	Noninterest Expense NoninterestExpense	11006000	usd
CY2023Q4	us-gaap	Noninterest Expense NoninterestExpense	11187000	usd
CY2022Q1	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	11752000	usd
CY2022Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	12156000	usd
CY2022Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	12308000	usd
CY2022Q4	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	11170000	usd
CY2023Q1	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	9644000	usd
CY2023Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	8929000	usd
CY2023Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	9039000	usd
CY2023Q4	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	8090000	usd
CY2022Q1	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	2047000	usd
CY2022Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	2159000	usd
CY2022Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	2217000	usd
CY2022Q4	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	1973000	usd
CY2023Q1	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	1673000	usd
CY2023Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	1535000	usd
CY2023Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	1565000	usd
CY2023Q4	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	1411000	usd
CY2022Q1	us-gaap	Net Income Loss NetIncomeLoss	9705000	usd
CY2022Q2	us-gaap	Net Income Loss NetIncomeLoss	9997000	usd
CY2022Q3	us-gaap	Net Income Loss NetIncomeLoss	10091000	usd
CY2022Q4	us-gaap	Net Income Loss NetIncomeLoss	9197000	usd
CY2023Q1	us-gaap	Net Income Loss NetIncomeLoss	7971000	usd
CY2023Q2	us-gaap	Net Income Loss NetIncomeLoss	7394000	usd
CY2023Q3	us-gaap	Net Income Loss NetIncomeLoss	7474000	usd
CY2023Q4	us-gaap	Net Income Loss NetIncomeLoss	6679000	usd
CY2022Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.89
CY2022Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.91
CY2022Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.92
CY2022Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.84
CY2023Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.73
CY2023Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.67
CY2023Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.68
CY2023Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.60
CY2022Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.88
CY2022Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.91
CY2022Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.91
CY2022Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.83
CY2023Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.72
CY2023Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.67
CY2023Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.67
CY2023Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.60
CY2022Q1	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-18343000	usd
CY2022Q2	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-12734000	usd
CY2022Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-14866000	usd
CY2022Q4	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	2943000	usd
CY2023Q1	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	4181000	usd
CY2023Q2	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-3244000	usd
CY2023Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-10071000	usd
CY2023Q4	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	14277000	usd
CY2022Q1	fnlc	Availableforsale Securities Transferredto Heldtomaturity Securities Unrealized Gain Loss AvailableforsaleSecuritiesTransferredtoHeldtomaturitySecuritiesUnrealizedGainLoss	9000	usd
CY2022Q2	fnlc	Availableforsale Securities Transferredto Heldtomaturity Securities Unrealized Gain Loss AvailableforsaleSecuritiesTransferredtoHeldtomaturitySecuritiesUnrealizedGainLoss	5000	usd
CY2022Q3	fnlc	Availableforsale Securities Transferredto Heldtomaturity Securities Unrealized Gain Loss AvailableforsaleSecuritiesTransferredtoHeldtomaturitySecuritiesUnrealizedGainLoss	6000	usd
CY2022Q4	fnlc	Availableforsale Securities Transferredto Heldtomaturity Securities Unrealized Gain Loss AvailableforsaleSecuritiesTransferredtoHeldtomaturitySecuritiesUnrealizedGainLoss	3000	usd
CY2023Q1	fnlc	Availableforsale Securities Transferredto Heldtomaturity Securities Unrealized Gain Loss AvailableforsaleSecuritiesTransferredtoHeldtomaturitySecuritiesUnrealizedGainLoss	4000	usd
CY2023Q2	fnlc	Availableforsale Securities Transferredto Heldtomaturity Securities Unrealized Gain Loss AvailableforsaleSecuritiesTransferredtoHeldtomaturitySecuritiesUnrealizedGainLoss	1000	usd
CY2023Q3	fnlc	Availableforsale Securities Transferredto Heldtomaturity Securities Unrealized Gain Loss AvailableforsaleSecuritiesTransferredtoHeldtomaturitySecuritiesUnrealizedGainLoss	1000	usd
CY2023Q4	fnlc	Availableforsale Securities Transferredto Heldtomaturity Securities Unrealized Gain Loss AvailableforsaleSecuritiesTransferredtoHeldtomaturitySecuritiesUnrealizedGainLoss	2000	usd
CY2022Q1	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	0	usd
CY2022Q2	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	146000	usd
CY2022Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	354000	usd
CY2022Q4	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	44000	usd
CY2023Q1	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	-2736000	usd
CY2023Q2	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	2872000	usd
CY2023Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	730000	usd
CY2023Q4	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	-1110000	usd
CY2022Q1	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Transition Asset Obligation Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetTransitionAssetObligationNetOfTax	0	usd
CY2022Q2	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Transition Asset Obligation Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetTransitionAssetObligationNetOfTax	0	usd
CY2022Q3	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Transition Asset Obligation Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetTransitionAssetObligationNetOfTax	0	usd
CY2022Q4	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Transition Asset Obligation Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetTransitionAssetObligationNetOfTax	-168000	usd
CY2023Q1	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Transition Asset Obligation Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetTransitionAssetObligationNetOfTax	0	usd
CY2023Q2	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Transition Asset Obligation Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetTransitionAssetObligationNetOfTax	0	usd
CY2023Q3	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Transition Asset Obligation Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetTransitionAssetObligationNetOfTax	0	usd
CY2023Q4	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Transition Asset Obligation Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetTransitionAssetObligationNetOfTax	-30000	usd
CY2022Q1	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-18334000	usd
CY2022Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-12583000	usd
CY2022Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-14506000	usd
CY2022Q4	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	3158000	usd
CY2023Q1	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	1449000	usd
CY2023Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-371000	usd
CY2023Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-9340000	usd
CY2023Q4	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	13199000	usd
CY2022Q1	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	-8629000	usd
CY2022Q2	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	-2586000	usd
CY2022Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	-4415000	usd
CY2022Q4	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	12355000	usd
CY2023Q1	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	9420000	usd
CY2023Q2	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	7023000	usd
CY2023Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	-1866000	usd
CY2023Q4	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	19878000	usd
CY2023	us-gaap	Number Of Businesses Acquired NumberOfBusinessesAcquired	0	acquistion
CY2022	us-gaap	Number Of Businesses Acquired NumberOfBusinessesAcquired	0	acquistion
CY2023	dei	Auditor Name AuditorName	Berry Dunn McNeil & Parker, LLC
CY2023	dei	Auditor Firm AuditorFirmId	136
CY2023	dei	Auditor Location AuditorLocation	Portland, Maine

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$FNLC
First Bancorp, Inc /ME/ Stock $fnlc

2024 Q1 Form 10-K Financial Statement

#000076520724000010 Filed on March 08, 2024

Income Statement

Balance Sheet

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Facts In Submission

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$FNLC First Bancorp, Inc /ME/ Stock $fnlc

2024 Q1 Form 10-K Financial Statement

#000076520724000010 Filed on March 08, 2024

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$FNLC
First Bancorp, Inc /ME/ Stock $fnlc