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

$fnlc Overview Financials Valuation SEC Filings Company Website

2021 Q3 Form 10-K Financial Statement

#000076520722000010 Filed on March 11, 2022

Income Statement

Concept	2021 Q3	2021	2020 Q4
Revenue	$19.59M	$77.08M	$19.13M
YoY Change	5.85%	-0.05%	-2.67%
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	$510.0K	$2.039M	$550.0K
YoY Change	-15.0%	-8.19%	1.85%
% of Gross Profit
Operating Expenses
YoY Change
Operating Profit
YoY Change
Interest Expense	$2.577M	$10.78M	$3.454M
YoY Change	-31.48%	-37.65%	-44.64%
% of Operating Profit
Other Income/Expense, Net
YoY Change
Pretax Income	$10.93M	$43.91M	$8.255M
YoY Change	28.97%	36.16%	3.88%
Income Tax	$1.915M	$7.644M	$1.285M
% Of Pretax Income	17.52%	17.41%	15.57%
Net Earnings	$9.014M	$36.27M	$6.970M
YoY Change	27.05%	33.69%	4.25%
Net Earnings / Revenue	46.02%	47.05%	36.43%
Basic Earnings Per Share	$0.83	$3.33	$0.64
Diluted Earnings Per Share	$0.82	$3.30	$0.63
COMMON SHARES
Basic Shares Outstanding	10.91M shares	10.90M shares	10.95M shares
Diluted Shares Outstanding	10.99M shares	10.99M shares

Balance Sheet

Concept	2021 Q3	2021	2020 Q4
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents	$27.13M		$26.21M
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	$29.11M	$28.90M	$27.25M
YoY Change	7.36%	5.86%	27.91%
Goodwill	$30.65M		$30.65M
YoY Change	2.82%		2.82%
Intangibles
YoY Change
Long-Term Investments
YoY Change
Other Assets		-$400.0K
YoY Change		-300.0%
Total Long-Term Assets
YoY Change
TOTAL ASSETS
Total Short-Term Assets
Total Long-Term Assets
Total Assets	$2.530B	$2.527B	$2.361B
YoY Change	10.14%	7.03%	14.14%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable
YoY Change
Accrued Expenses		$800.0K
YoY Change
Deferred Revenue
YoY Change
Short-Term Debt	$178.1M	$81.30M	$206.9M
YoY Change	-22.12%	17.32%	18.35%
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities		$800.0K
YoY Change		-98.85%
LONG-TERM LIABILITIES
Long-Term Debt	$0.00	$0.00	$0.00
YoY Change
Other Long-Term Liabilities	$24.40M	$21.00M	$30.90M
YoY Change	-19.47%	-32.04%	47.85%
Total Long-Term Liabilities	$24.40M	$21.00M	$30.90M
YoY Change	-19.47%	-32.04%	47.85%
TOTAL LIABILITIES
Total Short-Term Liabilities		$800.0K
Total Long-Term Liabilities	$24.40M	$21.00M	$30.90M
Total Liabilities	$2.291B	$2.281B	$2.138B
YoY Change	10.29%	6.73%	15.15%
SHAREHOLDERS EQUITY
Retained Earnings	$174.4M		$158.4M
YoY Change	12.67%		9.33%
Common Stock	$110.0K		$110.0K
YoY Change	0.92%		0.92%
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity	$238.7M	$245.7M	$223.7M
YoY Change
Total Liabilities & Shareholders Equity	$2.530B	$2.527B	$2.361B
YoY Change	10.14%	7.03%	14.14%

Cashflow Statement

Concept	2021 Q3	2021	2020 Q4
OPERATING ACTIVITIES
Net Income	$9.014M	$36.27M	$6.970M
YoY Change	27.05%	33.69%	4.25%
Depreciation, Depletion And Amortization	$510.0K	$2.039M	$550.0K
YoY Change	-15.0%	-8.19%	1.85%
Cash From Operating Activities	$12.89M	$56.69M	$1.640M
YoY Change	-18.57%	149.77%	-85.89%
INVESTING ACTIVITIES
Capital Expenditures	-$110.0K	$3.757M	$4.940M
YoY Change	-98.43%	47.91%	-909.84%
Acquisitions		$0.00
YoY Change		-100.0%
Other Investing Activities	-$85.83M	-$198.0M	-$40.42M
YoY Change	160.56%	-20.01%	-10.99%
Cash From Investing Activities	-$85.94M	-$201.7M	-$35.49M
YoY Change	115.23%	-19.32%	-22.88%
FINANCING ACTIVITIES
Cash Dividend Paid		$13.95M
YoY Change		4.64%
Common Stock Issuance & Retirement, Net		-$436.0K
YoY Change		-15.18%
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	73.09M	$139.5M	37.32M
YoY Change	195.91%	-41.68%	36.15%
NET CHANGE
Cash From Operating Activities	12.89M	$56.69M	1.640M
Cash From Investing Activities	-85.94M	-$201.7M	-35.49M
Cash From Financing Activities	73.09M	$139.5M	37.32M
Net Change In Cash	40.00K	-$5.578M	3.470M
YoY Change	-93.33%	-147.36%	-149.64%
FREE CASH FLOW
Cash From Operating Activities	$12.89M	$56.69M	$1.640M
Capital Expenditures	-$110.0K	$3.757M	$4.940M
Free Cash Flow	$13.00M	$52.94M	-$3.300M
YoY Change	-43.06%	162.61%	-126.98%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
CY2021	dei	Entity Central Index Key EntityCentralIndexKey	0000765207
CY2021	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2021
CY2021	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	FY
CY2021	dei	Amendment Flag AmendmentFlag	false
CY2021	dei	Document Transition Report DocumentTransitionReport	false
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CY2021	dei	Document Type DocumentType	10-K
CY2021	dei	Document Annual Report DocumentAnnualReport	true
CY2021	dei	Document Period End Date DocumentPeriodEndDate	2021-12-31
CY2021	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
CY2021	dei	Entity File Number EntityFileNumber	0-26589
CY2021	dei	Entity Registrant Name EntityRegistrantName	FIRST BANCORP, INC
CY2021	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	ME
CY2021	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	01-0404322
CY2021	dei	Entity Address Address Line1 EntityAddressAddressLine1	223 Main Street
CY2021	dei	Entity Address City Or Town EntityAddressCityOrTown	Damariscotta
CY2021	dei	Entity Address State Or Province EntityAddressStateOrProvince	ME
CY2021	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	04543
CY2021	dei	City Area Code CityAreaCode	207
CY2021	dei	Local Phone Number LocalPhoneNumber	563-3195
CY2021	dei	Security12b Title Security12bTitle	Common Stock, par value $0.01 per share
CY2021	dei	Trading Symbol TradingSymbol	FNLC
CY2021	dei	Security Exchange Name SecurityExchangeName	NASDAQ
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CY2021	dei	Entity Voluntary Filers EntityVoluntaryFilers	No
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CY2021	dei	Entity Filer Category EntityFilerCategory	Non-accelerated Filer
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CY2020	us-gaap	Noninterest Expense NoninterestExpense	39652000	USD
CY2019	us-gaap	Noninterest Expense NoninterestExpense	35172000	USD
CY2021	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	43913000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	32250000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	30260000	USD
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	7644000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	5121000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	4735000	USD
CY2021	us-gaap	Net Income Loss NetIncomeLoss	36269000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	27129000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	25525000	USD
CY2021	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	3.33
CY2020	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.50
CY2019	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.36
CY2021	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	3.30
CY2020	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.48
CY2019	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.34
CY2021	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-6727000	USD
CY2020	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	1352000	USD
CY2019	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	8708000	USD
CY2021	fnlc	Availableforsale Securities Transferredto Heldtomaturity Securities Unrealized Gain Loss AvailableforsaleSecuritiesTransferredtoHeldtomaturitySecuritiesUnrealizedGainLoss	46000	USD
CY2020	fnlc	Availableforsale Securities Transferredto Heldtomaturity Securities Unrealized Gain Loss AvailableforsaleSecuritiesTransferredtoHeldtomaturitySecuritiesUnrealizedGainLoss	49000	USD
CY2019	fnlc	Availableforsale Securities Transferredto Heldtomaturity Securities Unrealized Gain Loss AvailableforsaleSecuritiesTransferredtoHeldtomaturitySecuritiesUnrealizedGainLoss	15000	USD
CY2021	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	4932000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	-5029000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	-1341000	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
CY2020	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	-4000	USD
CY2019	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	13000	USD
CY2021	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-1672000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-3624000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	7369000	USD
CY2021	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	34597000	USD
CY2020	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	23505000	USD
CY2019	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	32894000	USD
CY2018Q4	us-gaap	Stockholders Equity StockholdersEquity	191542000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	25525000	USD
CY2019	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	8708000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	-1341000	USD
CY2019	fnlc	Availableforsale Securities Transferredto Heldtomaturity Securities Unrealized Gain Loss AvailableforsaleSecuritiesTransferredtoHeldtomaturitySecuritiesUnrealizedGainLoss	15000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	13000	USD
CY2019	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	32894000	USD
CY2019	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.19
CY2019	us-gaap	Dividends Cash DividendsCash	12963000	USD
CY2019	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	565000	USD
CY2019	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	183000	USD
CY2019	us-gaap	Stock Issued During Period Value Restricted Stock Award Gross StockIssuedDuringPeriodValueRestrictedStockAwardGross	0	USD
CY2019	us-gaap	Stock Issued During Period Value New Issues StockIssuedDuringPeriodValueNewIssues	653000	USD
CY2019Q4	us-gaap	Stockholders Equity StockholdersEquity	212508000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	27129000	USD
CY2020	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	1352000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	-5029000	USD
CY2020	fnlc	Availableforsale Securities Transferredto Heldtomaturity Securities Unrealized Gain Loss AvailableforsaleSecuritiesTransferredtoHeldtomaturitySecuritiesUnrealizedGainLoss	49000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-4000	USD
CY2020	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	23505000	USD
CY2020	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.23
CY2020	us-gaap	Dividends Cash DividendsCash	13453000	USD
CY2020	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	652000	USD
CY2020	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	156000	USD
CY2020	us-gaap	Stock Issued During Period Value Restricted Stock Award Gross StockIssuedDuringPeriodValueRestrictedStockAwardGross	0	USD
CY2020	us-gaap	Stock Issued During Period Value New Issues StockIssuedDuringPeriodValueNewIssues	670000	USD
CY2020Q4	us-gaap	Stockholders Equity StockholdersEquity	223726000	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
CY2021	us-gaap	Net Income Loss NetIncomeLoss	36269000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	27129000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	25525000	USD
CY2021	us-gaap	Depreciation Depreciation	2039000	USD
CY2020	us-gaap	Depreciation Depreciation	2221000	USD
CY2019	us-gaap	Depreciation Depreciation	1938000	USD
CY2021	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	999000	USD
CY2020	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-262000	USD
CY2019	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	336000	USD
CY2021	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	-375000	USD
CY2020	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	6050000	USD
CY2019	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	1250000	USD
CY2021	us-gaap	Payments For Origination Of Mortgage Loans Held For Sale PaymentsForOriginationOfMortgageLoansHeldForSale	106393000	USD
CY2020	us-gaap	Payments For Origination Of Mortgage Loans Held For Sale PaymentsForOriginationOfMortgageLoansHeldForSale	128375000	USD
CY2019	us-gaap	Payments For Origination Of Mortgage Loans Held For Sale PaymentsForOriginationOfMortgageLoansHeldForSale	37721000	USD
CY2020	us-gaap	Provision For Other Losses ProvisionForOtherLosses	45000	USD
CY2019	us-gaap	Provision For Other Losses ProvisionForOtherLosses	0	USD
CY2021	us-gaap	Proceeds From Sale Of Loans Held For Sale ProceedsFromSaleOfLoansHeldForSale	114491000	USD
CY2020	us-gaap	Proceeds From Sale Of Loans Held For Sale ProceedsFromSaleOfLoansHeldForSale	125982000	USD
CY2019	us-gaap	Proceeds From Sale Of Loans Held For Sale ProceedsFromSaleOfLoansHeldForSale	38218000	USD
CY2021	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	3078000	USD
CY2020	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	3308000	USD
CY2019	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	651000	USD
CY2021	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	23000	USD
CY2020	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	1155000	USD
CY2019	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	224000	USD
CY2021	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-2351000	USD
CY2020	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-1944000	USD
CY2019	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-1082000	USD
CY2021	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	91000	USD
CY2020	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	170000	USD
CY2019	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	113000	USD
CY2021	us-gaap	Provision For Other Losses ProvisionForOtherLosses	0	USD
CY2021	us-gaap	Share Based Compensation ShareBasedCompensation	856000	USD
CY2020	us-gaap	Share Based Compensation ShareBasedCompensation	652000	USD
CY2019	us-gaap	Share Based Compensation ShareBasedCompensation	565000	USD
CY2021	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	-18604000	USD
CY2020	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	17737000	USD
CY2019	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	7690000	USD
CY2021	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	-9332000	USD
CY2020	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	9347000	USD
CY2019	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	2802000	USD
CY2021	us-gaap	Gain Loss On Disposition Of Assets GainLossOnDispositionOfAssets	2000	USD
CY2020	us-gaap	Gain Loss On Disposition Of Assets GainLossOnDispositionOfAssets	19000	USD
CY2019	us-gaap	Gain Loss On Disposition Of Assets GainLossOnDispositionOfAssets	-386000	USD
CY2021	us-gaap	Other Depreciation And Amortization OtherDepreciationAndAmortization	309000	USD
CY2020	us-gaap	Other Depreciation And Amortization OtherDepreciationAndAmortization	311000	USD
CY2019	us-gaap	Other Depreciation And Amortization OtherDepreciationAndAmortization	307000	USD
CY2021	us-gaap	Amortization Of Acquisition Costs AmortizationOfAcquisitionCosts	69000	USD
CY2020	us-gaap	Amortization Of Acquisition Costs AmortizationOfAcquisitionCosts	43000	USD
CY2019	us-gaap	Amortization Of Acquisition Costs AmortizationOfAcquisitionCosts	43000	USD
CY2021	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	56693000	USD
CY2020	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	22698000	USD
CY2019	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	26053000	USD
CY2021	fnlc	Interest Interest Bearing Deposits In Other Banks Interest-InterestBearingDepositsInOtherBanks	10527000	USD
CY2020	fnlc	Interest Interest Bearing Deposits In Other Banks Interest-InterestBearingDepositsInOtherBanks	44841000	USD
CY2019	fnlc	Interest Interest Bearing Deposits In Other Banks Interest-InterestBearingDepositsInOtherBanks	-769000	USD
CY2021	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	19240000	USD
CY2020	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	103579000	USD
CY2019	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	8339000	USD
CY2021	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	104424000	USD
CY2020	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	141598000	USD
CY2019	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	78825000	USD
CY2021	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	80217000	USD
CY2020	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	81809000	USD
CY2019	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	24087000	USD
CY2021	us-gaap	Proceeds From Sale Of Other Real Estate ProceedsFromSaleOfOtherRealEstate	999000	USD
CY2020	us-gaap	Proceeds From Sale Of Other Real Estate ProceedsFromSaleOfOtherRealEstate	542000	USD
CY2019	us-gaap	Proceeds From Sale Of Other Real Estate ProceedsFromSaleOfOtherRealEstate	418000	USD
CY2021	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	141222000	USD
CY2020	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	197207000	USD
CY2019	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	98257000	USD
CY2021	us-gaap	Payments To Acquire Limited Partnership Interests PaymentsToAcquireLimitedPartnershipInterests	0	USD
CY2020	us-gaap	Payments To Acquire Limited Partnership Interests PaymentsToAcquireLimitedPartnershipInterests	717000	USD
CY2019	us-gaap	Payments To Acquire Limited Partnership Interests PaymentsToAcquireLimitedPartnershipInterests	0	USD
CY2021	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	85061000	USD
CY2020	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	165658000	USD
CY2019	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	71857000	USD
CY2021	us-gaap	Payments To Acquire Restricted Investments PaymentsToAcquireRestrictedInvestments	0	USD
CY2020	us-gaap	Payments To Acquire Restricted Investments PaymentsToAcquireRestrictedInvestments	1563000	USD
CY2019	us-gaap	Payments To Acquire Restricted Investments PaymentsToAcquireRestrictedInvestments	0	USD
CY2021	fnlc	Redemption Of Restricted Equity Securities RedemptionOfRestrictedEquitySecurities	5180000	USD
CY2020	fnlc	Redemption Of Restricted Equity Securities RedemptionOfRestrictedEquitySecurities	0	USD
CY2019	fnlc	Redemption Of Restricted Equity Securities RedemptionOfRestrictedEquitySecurities	2604000	USD
CY2021	us-gaap	Payments To Acquire Finance Receivables PaymentsToAcquireFinanceReceivables	171245000	USD
CY2020	us-gaap	Payments To Acquire Finance Receivables PaymentsToAcquireFinanceReceivables	159080000	USD
CY2019	us-gaap	Payments To Acquire Finance Receivables PaymentsToAcquireFinanceReceivables	59635000	USD
CY2021	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	3757000	USD
CY2020	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	2540000	USD
CY2019	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	1573000	USD
CY2021	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	3000	USD
CY2020	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	67000	USD
CY2019	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	0	USD
CY2021	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	0	USD
CY2020	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	6060000	USD
CY2019	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	0	USD
CY2021	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-201749000	USD
CY2021	us-gaap	Proceeds From Issuance Of Other Long Term Debt ProceedsFromIssuanceOfOtherLongTermDebt	0	USD
CY2020	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-250071000	USD
CY2019	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-116280000	USD
CY2021	fnlc	Increase Decreasein Demand Deposits Savings Depositsand Money Market Accounts IncreaseDecreaseinDemandDepositsSavingsDepositsandMoneyMarketAccounts	318066000	USD
CY2020	fnlc	Increase Decreasein Demand Deposits Savings Depositsand Money Market Accounts IncreaseDecreaseinDemandDepositsSavingsDepositsandMoneyMarketAccounts	262035000	USD
CY2019	fnlc	Increase Decreasein Demand Deposits Savings Depositsand Money Market Accounts IncreaseDecreaseinDemandDepositsSavingsDepositsandMoneyMarketAccounts	24811000	USD
CY2021	us-gaap	Increase Decrease In Time Deposits IncreaseDecreaseInTimeDeposits	-39380000	USD
CY2020	us-gaap	Increase Decrease In Time Deposits IncreaseDecreaseInTimeDeposits	-87151000	USD
CY2019	us-gaap	Increase Decrease In Time Deposits IncreaseDecreaseInTimeDeposits	98570000	USD
CY2020	us-gaap	Proceeds From Issuance Of Other Long Term Debt ProceedsFromIssuanceOfOtherLongTermDebt	55000000	USD
CY2019	us-gaap	Proceeds From Issuance Of Other Long Term Debt ProceedsFromIssuanceOfOtherLongTermDebt	0	USD
CY2021	us-gaap	Repayments Of Other Long Term Debt RepaymentsOfOtherLongTermDebt	7000	USD
CY2020	us-gaap	Repayments Of Other Long Term Debt RepaymentsOfOtherLongTermDebt	10007000	USD
CY2019	us-gaap	Repayments Of Other Long Term Debt RepaymentsOfOtherLongTermDebt	25362000	USD
CY2021	us-gaap	Proceeds From Repayments Of Short Term Debt ProceedsFromRepaymentsOfShortTermDebt	-125689000	USD
CY2020	us-gaap	Proceeds From Repayments Of Short Term Debt ProceedsFromRepaymentsOfShortTermDebt	32090000	USD
CY2019	us-gaap	Proceeds From Repayments Of Short Term Debt ProceedsFromRepaymentsOfShortTermDebt	0	USD
CY2021	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	253000	USD
CY2020	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	156000	USD
CY2019	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	183000	USD
CY2021	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	689000	USD
CY2020	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	670000	USD
CY2019	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	653000	USD
CY2021	us-gaap	Payments Of Dividends PaymentsOfDividends	13948000	USD
CY2020	us-gaap	Payments Of Dividends PaymentsOfDividends	13329000	USD
CY2019	us-gaap	Payments Of Dividends PaymentsOfDividends	12963000	USD
CY2021	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	139478000	USD
CY2020	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	239152000	USD
CY2019	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	85526000	USD
CY2021	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-5578000	USD
CY2020	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	11779000	USD
CY2019	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-4701000	USD
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	26212000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	14433000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	19134000	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
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	14433000	USD
CY2021	us-gaap	Interest Paid Net InterestPaidNet	11141000	USD
CY2020	us-gaap	Interest Paid Net InterestPaidNet	17560000	USD
CY2019	us-gaap	Interest Paid Net InterestPaidNet	26088000	USD
CY2021	us-gaap	Income Taxes Paid IncomeTaxesPaid	6548000	USD
CY2020	us-gaap	Income Taxes Paid IncomeTaxesPaid	5049000	USD
CY2019	us-gaap	Income Taxes Paid IncomeTaxesPaid	3994000	USD
CY2021	us-gaap	Transfer Of Other Real Estate TransferOfOtherRealEstate	0	USD
CY2020	us-gaap	Transfer Of Other Real Estate TransferOfOtherRealEstate	1046000	USD
CY2019	us-gaap	Transfer Of Other Real Estate TransferOfOtherRealEstate	0	USD
CY2021	us-gaap	Fair Value Of Assets Acquired FairValueOfAssetsAcquired	0	USD
CY2020	us-gaap	Fair Value Of Assets Acquired FairValueOfAssetsAcquired	25328000	USD
CY2019	us-gaap	Fair Value Of Assets Acquired FairValueOfAssetsAcquired	0	USD
CY2021	us-gaap	Liabilities Assumed1 LiabilitiesAssumed1	0	USD
CY2020	us-gaap	Liabilities Assumed1 LiabilitiesAssumed1	19268000	USD
CY2019	us-gaap	Liabilities Assumed1 LiabilitiesAssumed1	0	USD
CY2020Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	511000	USD
CY2020Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	511000	USD
CY2021Q4	fnlc	Number Of Offices NumberOfOffices	17	office
CY2021	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 accounting principles generally accepted in the United States of America ("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 allowance for loan losses, the valuations of mortgage servicing rights, derivative financial instruments, the securities portfolio and other-than-temporary impairment of securities, and goodwill.</span></div>
CY2021	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 Bank recognizes all derivatives in the consolidated balance sheets at fair value. On the date the Bank enters into the derivative contract, the Bank designates the derivative 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 Bank formally documents relationships between hedging instruments and hedged items, as well as its risk management objectives and strategy for undertaking various hedge transactions. The Bank also assesses, both at the hedge’s inception and on an ongoing basis, 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 other comprehensive income (loss) and are reclassified into earnings when the forecasted transaction or related cash flows affect earnings. </span></div>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 are recorded at fair value with changes in fair value recorded in earnings. The Bank discontinues hedge accounting when it determines 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.
CY2021	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 Loan Losses</span></div><div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Loans considered to be uncollectible are charged against the allowance for loan losses. The allowance for loan losses is maintained at a level determined by Management to be appropriate to absorb probable losses. This allowance is increased by provisions charged to operating expenses and recoveries on loans previously charged off. Arriving at an appropriate level of allowance for loan losses necessarily involves a high degree of judgment. In determining the appropriate level of allowance for loan losses, Management takes into consideration several factors, including reviews of individual non-performing loans and performing loans listed on the watch report requiring periodic evaluation, loan portfolio size by category, recent loss experience, delinquency trends and current economic conditions. For all loan classes, loans over 30 days past due are considered delinquent. Impaired loans include troubled debt restructured ("TDR") loans and loans placed on non-accrual status when, based on current information and events, it is probable that the Bank will be unable to collect all amounts due according to the contractual terms of the loan agreement. These loans are measured at the present value of expected future cash flows discounted at the loan's effective interest rate or at the fair value of the collateral if the loan is collateral dependent. Management takes into consideration impaired loans in addition to the above mentioned factors in determining the appropriate level of allowance for loan losses.</span></div>
CY2021	us-gaap	Number Of Operating Segments NumberOfOperatingSegments	1	segment
CY2021Q4	us-gaap	Debt Securities Available For Sale Amortized Cost Excluding Accrued Interest After Allowance For Credit Loss DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLoss	322741000	USD
CY2021Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	2954000	USD
CY2021Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	8599000	USD
CY2021Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	3312000	USD
CY2021Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	375327000	USD
CY2021Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	5129000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest DebtSecuritiesAvailableForSaleExcludingAccruedInterest	320566000	USD
CY2021Q4	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest Before Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss	370040000	USD
CY2021Q4	us-gaap	Federal Home Loan Bank Stock FederalHomeLoanBankStock	4328000	USD
CY2021Q4	us-gaap	Federal Home Loan Bank Stock FederalHomeLoanBankStock	4328000	USD
CY2021Q4	us-gaap	Federal Reserve Bank Stock FederalReserveBankStock	1037000	USD
CY2021Q4	us-gaap	Federal Reserve Bank Stock FederalReserveBankStock	1037000	USD
CY2021Q4	us-gaap	Federal Home Loan Bank Stock And Federal Reserve Bank Stock FederalHomeLoanBankStockAndFederalReserveBankStock	5365000	USD
CY2021Q4	us-gaap	Federal Home Loan Bank Stock And Federal Reserve Bank Stock FederalHomeLoanBankStockAndFederalReserveBankStock	5365000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Amortized Cost Excluding Accrued Interest After Allowance For Credit Loss DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLoss	307036000	USD
CY2020Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	7272000	USD
CY2020Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	932000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest DebtSecuritiesAvailableForSaleExcludingAccruedInterest	313376000	USD
CY2020Q4	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest Before Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss	365613000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	11739000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	218000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	377134000	USD
CY2020Q4	us-gaap	Federal Home Loan Bank Stock FederalHomeLoanBankStock	9508000	USD
CY2020Q4	us-gaap	Federal Home Loan Bank Stock FederalHomeLoanBankStock	9508000	USD
CY2020Q4	us-gaap	Federal Reserve Bank Stock FederalReserveBankStock	1037000	USD
CY2020Q4	us-gaap	Federal Reserve Bank Stock FederalReserveBankStock	1037000	USD
CY2020Q4	us-gaap	Federal Home Loan Bank Stock And Federal Reserve Bank Stock FederalHomeLoanBankStockAndFederalReserveBankStock	10545000	USD
CY2020Q4	us-gaap	Federal Home Loan Bank Stock And Federal Reserve Bank Stock FederalHomeLoanBankStockAndFederalReserveBankStock	10545000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Maturities Within One Year Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost	0	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Maturities Within One Year Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue	0	USD
CY2021Q4	us-gaap	Held To Maturity Securities Debt Maturities Within One Year Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount	2515000	USD
CY2021Q4	us-gaap	Held To Maturity Securities Debt Maturities Within One Year Fair Value HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue	2521000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost	5004000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	5173000	USD
CY2021Q4	us-gaap	Held To Maturity Securities Debt Maturities After One Through Five Years Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsNetCarryingAmount	17624000	USD
CY2021Q4	us-gaap	Held To Maturity Securities Debt Maturities After One Through Five Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	18338000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost	52782000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	53057000	USD
CY2021Q4	us-gaap	Held To Maturity Securities Debt Maturities After Five Through Ten Years Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsNetCarryingAmount	174982000	USD
CY2021Q4	us-gaap	Held To Maturity Securities Debt Maturities After Five Through Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	180081000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost	264955000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue	262336000	USD
CY2021Q4	us-gaap	Held To Maturity Securities Debt Maturities After Ten Years Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsNetCarryingAmount	174919000	USD
CY2021Q4	us-gaap	Held To Maturity Securities Debt Maturities After Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue	174387000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Amortized Cost Excluding Accrued Interest After Allowance For Credit Loss DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLoss	322741000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest DebtSecuritiesAvailableForSaleExcludingAccruedInterest	320566000	USD
CY2021Q4	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest Before Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss	370040000	USD
CY2021Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	375327000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities Within One Year Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost	117000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities Within One Year Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue	120000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Debt Maturities Within One Year Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount	3607000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Debt Maturities Within One Year Fair Value HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue	3641000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost	17718000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	17915000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Debt Maturities After One Through Five Years Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsNetCarryingAmount	30867000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Debt Maturities After One Through Five Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	31792000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost	49697000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	51001000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Debt Maturities After Five Through Ten Years Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsNetCarryingAmount	183679000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Debt Maturities After Five Through Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	190153000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost	239504000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue	244340000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Debt Maturities After Ten Years Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsNetCarryingAmount	147460000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Debt Maturities After Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue	151548000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Amortized Cost Excluding Accrued Interest After Allowance For Credit Loss DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLoss	307036000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest DebtSecuritiesAvailableForSaleExcludingAccruedInterest	313376000	USD
CY2020Q4	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest Before Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss	365613000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	377134000	USD
CY2021	us-gaap	Proceeds From Sale And Maturity Of Marketable Securities ProceedsFromSaleAndMaturityOfMarketableSecurities	19240000	USD
CY2020	us-gaap	Proceeds From Sale And Maturity Of Marketable Securities ProceedsFromSaleAndMaturityOfMarketableSecurities	112179000	USD
CY2019	us-gaap	Proceeds From Sale And Maturity Of Marketable Securities ProceedsFromSaleAndMaturityOfMarketableSecurities	9229000	USD
CY2021	fnlc	Debt Securities Realized Gain DebtSecuritiesRealizedGain	628000	USD
CY2020	fnlc	Debt Securities Realized Gain DebtSecuritiesRealizedGain	1689000	USD
CY2019	fnlc	Debt Securities Realized Gain DebtSecuritiesRealizedGain	224000	USD
CY2021	fnlc	Debt Securities Realized Loss DebtSecuritiesRealizedLoss	605000	USD
CY2020	fnlc	Debt Securities Realized Loss DebtSecuritiesRealizedLoss	534000	USD
CY2019	fnlc	Debt Securities Realized Loss DebtSecuritiesRealizedLoss	0	USD
CY2021	us-gaap	Debt Securities Gain Loss DebtSecuritiesGainLoss	23000	USD
CY2020	us-gaap	Debt Securities Gain Loss DebtSecuritiesGainLoss	1155000	USD
CY2019	us-gaap	Debt Securities Gain Loss DebtSecuritiesGainLoss	224000	USD
CY2021	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	5000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	243000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	47000	USD
CY2021Q4	fnlc	Number Of Securities Temporarily Impaired NumberOfSecuritiesTemporarilyImpaired	163	security
CY2021Q4	fnlc	Number Of Securities Temporarily Impaired Twelve Months NumberOfSecuritiesTemporarilyImpairedTwelveMonths	27	security
CY2021	fnlc	Length Of Time Securities Temporarily Impaired LengthOfTimeSecuritiesTemporarilyImpaired	P12M
CY2021Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	273453000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	6144000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	55942000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	2297000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	329395000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	8441000	USD
CY2020Q4	fnlc	Number Of Securities Temporarily Impaired NumberOfSecuritiesTemporarilyImpaired	50	security
CY2020Q4	fnlc	Number Of Securities Temporarily Impaired Twelve Months NumberOfSecuritiesTemporarilyImpairedTwelveMonths	10	security
CY2014Q3	fnlc	Availablefor Sale Securities Transferred Securityat Fair Value AvailableforSaleSecuritiesTransferredSecurityatFairValue	89757000	USD
CY2020	fnlc	Length Of Time Securities Temporarily Impaired LengthOfTimeSecuritiesTemporarilyImpaired	P12M
CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	99070000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	1062000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	3878000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	88000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	102948000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	1150000	USD
CY2014Q3	fnlc	Availablefor Sale Securities Transferred Securityat Carrying Value AvailableforSaleSecuritiesTransferredSecurityatCarryingValue	89780000	USD
CY2014Q3	fnlc	Availableforsale Securities Transferredto Heldtomaturity Securities Accumulated Unrealized Gain Loss AvailableforsaleSecuritiesTransferredtoHeldtomaturitySecuritiesAccumulatedUnrealizedGainLoss	-15000	USD
CY2021Q4	fnlc	Other Comprehensive Income Loss Accumulated Unrealized Gain Losson Transferof Availableforsale Securitiesto Heldtomaturity OtherComprehensiveIncomeLossAccumulatedUnrealizedGainLossonTransferofAvailableforsaleSecuritiestoHeldtomaturity	-87000	USD
CY2020Q4	fnlc	Other Comprehensive Income Loss Accumulated Unrealized Gain Losson Transferof Availableforsale Securitiesto Heldtomaturity OtherComprehensiveIncomeLossAccumulatedUnrealizedGainLossonTransferofAvailableforsaleSecuritiestoHeldtomaturity	-133000	USD
CY2021Q4	fnlc	Number Of States In New England Where Fhlb Serve NumberOfStatesInNewEnglandWhereFhlbServe	6	state
CY2021Q4	us-gaap	Federal Home Loan Bank Stock FederalHomeLoanBankStock	4328000	USD
CY2020Q4	us-gaap	Federal Home Loan Bank Stock FederalHomeLoanBankStock	9508000	USD
CY2020Q4	us-gaap	Federal Reserve Bank Stock FederalReserveBankStock	1037000	USD
CY2021Q4	us-gaap	Federal Reserve Bank Stock FederalReserveBankStock	1037000	USD
CY2021Q4	fnlc	Restricted Equity Securities Unrealized Losses RestrictedEquitySecuritiesUnrealizedLosses	0	USD
CY2021Q4	fnlc	Residential Mortgage Loans Serviced For Others Outstanding Principal ResidentialMortgageLoansServicedForOthersOutstandingPrincipal	356522000	USD
CY2020Q4	fnlc	Residential Mortgage Loans Serviced For Others Outstanding Principal ResidentialMortgageLoansServicedForOthersOutstandingPrincipal	318459000	USD
CY2021	fnlc	Net Gain From Sale Of Loans NetGainFromSaleOfLoans	3078000	USD
CY2020	fnlc	Net Gain From Sale Of Loans NetGainFromSaleOfLoans	3308000	USD
CY2019	fnlc	Net Gain From Sale Of Loans NetGainFromSaleOfLoans	651000	USD
CY2021	us-gaap	Servicing Asset At Fair Value Additions ServicingAssetAtFairValueAdditions	1042000	USD
CY2021	us-gaap	Amortization Of Mortgage Servicing Rights Ms Rs AmortizationOfMortgageServicingRightsMSRs	660000	USD
CY2021Q4	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	3041000	USD
CY2020	us-gaap	Servicing Asset At Fair Value Additions ServicingAssetAtFairValueAdditions	1160000	USD
CY2020	us-gaap	Amortization Of Mortgage Servicing Rights Ms Rs AmortizationOfMortgageServicingRightsMSRs	352000	USD
CY2020Q4	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	1985000	USD
CY2021	fnlc	Movingaverageofweeklyprepaymentdata Movingaverageofweeklyprepaymentdata	P3M
CY2021	us-gaap	Servicing Assets And Servicing Liabilities At Fair Value Assumptions Used To Estimate Fair Value Prepayment Speed ServicingAssetsAndServicingLiabilitiesAtFairValueAssumptionsUsedToEstimateFairValuePrepaymentSpeed	0.1013
CY2021	fnlc	Servicing Assets And Servicing Liabilities At Fair Value Assumptions Used To Estimate Fair Value Discount Rate Adjustment Factor ServicingAssetsAndServicingLiabilitiesAtFairValueAssumptionsUsedToEstimateFairValueDiscountRateAdjustmentFactor	0.0900
CY2021Q4	fnlc	Mortgage Servicing Rights Gross MortgageServicingRightsGross	8341000	USD
CY2020Q4	fnlc	Mortgage Servicing Rights Gross MortgageServicingRightsGross	7299000	USD
CY2021Q4	fnlc	Accumulated Amortization Mortgage Servicing Rights AccumulatedAmortizationMortgageServicingRights	5644000	USD
CY2020Q4	fnlc	Accumulated Amortization Mortgage Servicing Rights AccumulatedAmortizationMortgageServicingRights	4985000	USD
CY2021Q4	us-gaap	Servicing Asset At Amortized Value ServicingAssetAtAmortizedValue	2697000	USD
CY2020Q4	us-gaap	Servicing Asset At Amortized Value ServicingAssetAtAmortizedValue	2314000	USD
CY2021	us-gaap	Servicing Asset At Amortized Cost Other Than Temporary Impairments ServicingAssetAtAmortizedCostOtherThanTemporaryImpairments	26000	USD
CY2020	us-gaap	Servicing Asset At Amortized Cost Other Than Temporary Impairments ServicingAssetAtAmortizedCostOtherThanTemporaryImpairments	358000	USD
CY2021Q4	us-gaap	Servicing Asset At Amortized Value Fair Value ServicingAssetAtAmortizedValueFairValue	2671000	USD
CY2020Q4	us-gaap	Servicing Asset At Amortized Value Fair Value ServicingAssetAtAmortizedValueFairValue	1956000	USD
CY2021Q4	us-gaap	Notes Receivable Gross NotesReceivableGross	1647649000	USD
CY2021Q4	fnlc	Percentage Of Loans Receivable By Type PercentageOfLoansReceivableByType	1.000
CY2020Q4	us-gaap	Notes Receivable Gross NotesReceivableGross	1476761000	USD
CY2020Q4	fnlc	Percentage Of Loans Receivable By Type PercentageOfLoansReceivableByType	1.000
CY2021Q4	us-gaap	Loans And Leases Receivable Deferred Income LoansAndLeasesReceivableDeferredIncome	7890000	USD
CY2020Q4	us-gaap	Loans And Leases Receivable Deferred Income LoansAndLeasesReceivableDeferredIncome	6931000	USD
CY2021Q4	us-gaap	Federal Home Loan Bank Advances General Debt Obligations Disclosures Collateral Pledged1 FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledged1	364968000	USD
CY2020Q4	us-gaap	Federal Home Loan Bank Advances General Debt Obligations Disclosures Collateral Pledged1 FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledged1	378183000	USD
CY2021Q4	us-gaap	Loans Pledged As Collateral LoansPledgedAsCollateral	295090000	USD
CY2020Q4	us-gaap	Loans Pledged As Collateral LoansPledgedAsCollateral	259599000	USD
CY2021Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	5602000	USD
CY2020Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	6721000	USD
CY2021	us-gaap	Loans And Leases Receivable Impaired Interest Lost On Nonaccrual Loans LoansAndLeasesReceivableImpairedInterestLostOnNonaccrualLoans	345000	USD
CY2020	us-gaap	Loans And Leases Receivable Impaired Interest Lost On Nonaccrual Loans LoansAndLeasesReceivableImpairedInterestLostOnNonaccrualLoans	558000	USD
CY2021Q4	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	32000	USD
CY2020Q4	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	1505000	USD
CY2021Q4	us-gaap	Due From Related Parties DueFromRelatedParties	42784000	USD
CY2020Q4	us-gaap	Due From Related Parties DueFromRelatedParties	36880000	USD
CY2020Q4	fnlc	Related Party Loan Receivable Aggregated Over60000 Dollars RelatedPartyLoanReceivableAggregatedOver60000Dollars	21214000	USD
CY2019Q4	fnlc	Related Party Loan Receivable Aggregated Over60000 Dollars RelatedPartyLoanReceivableAggregatedOver60000Dollars	21134000	USD
CY2021	fnlc	Loansand Leases Receivables Related Parties Additions Aggregated Over60000 Dollars LoansandLeasesReceivablesRelatedPartiesAdditionsAggregatedOver60000Dollars	10074000	USD
CY2020	fnlc	Loansand Leases Receivables Related Parties Additions Aggregated Over60000 Dollars LoansandLeasesReceivablesRelatedPartiesAdditionsAggregatedOver60000Dollars	3544000	USD
CY2021	fnlc	Loansand Leases Receivables Related Parties Collections Aggregated Over60000 Dollars LoansandLeasesReceivablesRelatedPartiesCollectionsAggregatedOver60000Dollars	2498000	USD
CY2020	fnlc	Loansand Leases Receivables Related Parties Collections Aggregated Over60000 Dollars LoansandLeasesReceivablesRelatedPartiesCollectionsAggregatedOver60000Dollars	3138000	USD
CY2021	fnlc	Loansand Leases Receivables Related Parties Retired Director Aggregated Over60000 Dollars LoansandLeasesReceivablesRelatedPartiesRetiredDirectorAggregatedOver60000Dollars	2483000	USD
CY2020	fnlc	Loansand Leases Receivables Related Parties Retired Director Aggregated Over60000 Dollars LoansandLeasesReceivablesRelatedPartiesRetiredDirectorAggregatedOver60000Dollars	326000	USD
CY2021Q4	fnlc	Related Party Loan Receivable Aggregated Over60000 Dollars RelatedPartyLoanReceivableAggregatedOver60000Dollars	26307000	USD
CY2020Q4	fnlc	Related Party Loan Receivable Aggregated Over60000 Dollars RelatedPartyLoanReceivableAggregatedOver60000Dollars	21214000	USD
CY2021Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	1647649000	USD
CY2021Q4	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	32000	USD
CY2020Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	1476761000	USD
CY2020Q4	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	1505000	USD
CY2021Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	5602000	USD
CY2020Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	6721000	USD
CY2021	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	13121000	USD
CY2020	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	21088000	USD
CY2019	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	31557000	USD
CY2021	us-gaap	Impaired Financing Receivable Interest Income Cash Basis Method ImpairedFinancingReceivableInterestIncomeCashBasisMethod	242000	USD
CY2020	us-gaap	Impaired Financing Receivable Interest Income Cash Basis Method ImpairedFinancingReceivableInterestIncomeCashBasisMethod	478000	USD
CY2019	us-gaap	Impaired Financing Receivable Interest Income Cash Basis Method ImpairedFinancingReceivableInterestIncomeCashBasisMethod	735000	USD
CY2021Q4	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	12052000	USD
CY2020Q4	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	16039000	USD
CY2021Q4	fnlc	Impaired Financing Receivable With No Allowance ImpairedFinancingReceivableWithNoAllowance	8968000	USD
CY2020Q4	fnlc	Impaired Financing Receivable With No Allowance ImpairedFinancingReceivableWithNoAllowance	12098000	USD
CY2021Q4	fnlc	Impaired Financing Receivable With Allowance ImpairedFinancingReceivableWithAllowance	3084000	USD
CY2020Q4	fnlc	Impaired Financing Receivable With Allowance ImpairedFinancingReceivableWithAllowance	3941000	USD
CY2021Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	576000	USD
CY2020Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	462000	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	us-gaap	Impaired Financing Receivable With No Related Allowance Interest Income Cash Basis Method ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeCashBasisMethod	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	us-gaap	Impaired Financing Receivable With Related Allowance Interest Income Cash Basis Method ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeCashBasisMethod	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	us-gaap	Impaired Financing Receivable Interest Income Cash Basis Method ImpairedFinancingReceivableInterestIncomeCashBasisMethod	242000	USD
CY2020Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment	12098000	USD
CY2020Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance	13806000	USD
CY2020	us-gaap	Impaired Financing Receivable With No Related Allowance Average Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment	15473000	USD
CY2020	us-gaap	Impaired Financing Receivable With No Related Allowance Interest Income Cash Basis Method ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeCashBasisMethod	336000	USD
CY2020Q4	us-gaap	Impaired Financing Receivable With Related Allowance Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment	3941000	USD
CY2020Q4	us-gaap	Impaired Financing Receivable With Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance	4036000	USD
CY2020Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	462000	USD
CY2020	us-gaap	Impaired Financing Receivable With Related Allowance Average Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment	5615000	USD
CY2020	us-gaap	Impaired Financing Receivable With Related Allowance Interest Income Cash Basis Method ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeCashBasisMethod	142000	USD
CY2020Q4	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	16039000	USD
CY2020Q4	us-gaap	Impaired Financing Receivable Unpaid Principal Balance ImpairedFinancingReceivableUnpaidPrincipalBalance	17842000	USD
CY2020Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	462000	USD
CY2020	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	21088000	USD
CY2020	us-gaap	Impaired Financing Receivable Interest Income Cash Basis Method ImpairedFinancingReceivableInterestIncomeCashBasisMethod	478000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment	18212000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance	20330000	USD
CY2019	us-gaap	Impaired Financing Receivable With No Related Allowance Average Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment	20542000	USD
CY2019	us-gaap	Impaired Financing Receivable With No Related Allowance Interest Income Cash Basis Method ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeCashBasisMethod	593000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable With Related Allowance Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment	11062000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable With Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance	11848000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	2213000	USD
CY2019	us-gaap	Impaired Financing Receivable With Related Allowance Average Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment	11015000	USD
CY2019	us-gaap	Impaired Financing Receivable With Related Allowance Interest Income Cash Basis Method ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeCashBasisMethod	142000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	29274000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable Unpaid Principal Balance ImpairedFinancingReceivableUnpaidPrincipalBalance	32178000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	2213000	USD
CY2019	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	31557000	USD
CY2019	us-gaap	Impaired Financing Receivable Interest Income Cash Basis Method ImpairedFinancingReceivableInterestIncomeCashBasisMethod	735000	USD
CY2021	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	60	loan
CY2021Q4	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	8341000	USD
CY2020	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	74	loan
CY2020Q4	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	11534000	USD
CY2021	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	60	loan
CY2021Q4	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	8341000	USD
CY2021Q4	fnlc	Troubled Debt Restructuring Loansand Leases Receivable Specific Allowance TroubledDebtRestructuringLoansandLeasesReceivableSpecificAllowance	532000	USD
CY2020	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	74	loan
CY2020Q4	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	11534000	USD
CY2020Q4	fnlc	Troubled Debt Restructuring Loansand Leases Receivable Specific Allowance TroubledDebtRestructuringLoansandLeasesReceivableSpecificAllowance	369000	USD
CY2021Q4	fnlc	Financing Receivable Modifications Number Of Contracts Greater Than30 Days Past Due Place In Tdr In Previous12 Months FinancingReceivableModificationsNumberOfContractsGreaterThan30DaysPastDuePlaceInTDRInPrevious12Months	5	loan
CY2021Q4	fnlc	Financing Receivable Recorded Investment Greater Than30 Days Past Due FinancingReceivableRecordedInvestmentGreaterThan30DaysPastDue	349000	USD
CY2021	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	1	loan
CY2021Q4	fnlc	Financing Receivable Modifications Number Of Contracts Greater Than30 Days Past Due Place In Tdr In Previous12 Months FinancingReceivableModificationsNumberOfContractsGreaterThan30DaysPastDuePlaceInTDRInPrevious12Months	5	loan
CY2021Q4	fnlc	Financing Receivable Recorded Investment Greater Than30 Days Past Due Placed In Tdr In Previous12 Months FinancingReceivableRecordedInvestmentGreaterThan30DaysPastDuePlacedInTDRInPrevious12Months	349000	USD
CY2021Q4	fnlc	Financing Receivable Recorded Investment Greaterthan30 Days Past Due Placedin Td Rin Previous12 Months Specific Allowanceduring Period FinancingReceivableRecordedInvestmentGreaterthan30DaysPastDuePlacedinTDRinPrevious12MonthsSpecificAllowanceduringPeriod	0	USD
CY2020Q4	fnlc	Financing Receivable Modifications Number Of Contracts Greater Than30 Days Past Due Place In Tdr In Previous12 Months FinancingReceivableModificationsNumberOfContractsGreaterThan30DaysPastDuePlaceInTDRInPrevious12Months	14	loan
CY2020Q4	fnlc	Financing Receivable Recorded Investment Greater Than30 Days Past Due FinancingReceivableRecordedInvestmentGreaterThan30DaysPastDue	1577000	USD
CY2020	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	1	loan
CY2020Q4	fnlc	Financing Receivable Modifications Number Of Contracts Greater Than30 Days Past Due Place In Tdr In Previous12 Months FinancingReceivableModificationsNumberOfContractsGreaterThan30DaysPastDuePlaceInTDRInPrevious12Months	14	loan
CY2020Q4	fnlc	Financing Receivable Recorded Investment Greater Than30 Days Past Due Placed In Tdr In Previous12 Months FinancingReceivableRecordedInvestmentGreaterThan30DaysPastDuePlacedInTDRInPrevious12Months	1577000	USD
CY2020Q4	fnlc	Financing Receivable Recorded Investment Greaterthan30 Days Past Due Placedin Td Rin Previous12 Months Specific Allowanceduring Period FinancingReceivableRecordedInvestmentGreaterthan30DaysPastDuePlacedinTDRinPrevious12MonthsSpecificAllowanceduringPeriod	97000	USD
CY2021	fnlc	Financing Receivable Modifications Number Of Contracts During Period FinancingReceivableModificationsNumberOfContractsDuringPeriod	4	loan
CY2021	fnlc	Financing Receivable Modifications Number Of Contracts During Period FinancingReceivableModificationsNumberOfContractsDuringPeriod	4	loan
CY2021	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	473000	USD
CY2021	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	451000	USD
CY2021	fnlc	Troubled Debt Restructuring Loans And Leases Receivable Specific Allowance Current Period TroubledDebtRestructuringLoansAndLeasesReceivableSpecificAllowanceCurrentPeriod	247000	USD
CY2020	fnlc	Financing Receivable Modifications Number Of Contracts During Period FinancingReceivableModificationsNumberOfContractsDuringPeriod	3	loan
CY2020	fnlc	Financing Receivable Modifications Number Of Contracts During Period FinancingReceivableModificationsNumberOfContractsDuringPeriod	3	loan
CY2020	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	242000	USD
CY2020	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	193000	USD
CY2020	fnlc	Troubled Debt Restructuring Loans And Leases Receivable Specific Allowance Current Period TroubledDebtRestructuringLoansAndLeasesReceivableSpecificAllowanceCurrentPeriod	21000	USD
CY2021Q4	fnlc	Financing Receivable Modifications Number Of Contracts Involved In Bankruptcy During Period FinancingReceivableModificationsNumberOfContractsInvolvedInBankruptcyDuringPeriod	8	loan
CY2021Q4	fnlc	Financing Receivable Loans Classified As Troubled Debt Restructurings That Are Involved In Bankruptcy FinancingReceivableLoansClassifiedAsTroubledDebtRestructuringsThatAreInvolvedInBankruptcy	950000	USD
CY2021Q4	fnlc	Financing Receivable Number Of Loans Classified As Troubled Debt Restructurings That Were On Non Accrual Status FinancingReceivableNumberOfLoansClassifiedAsTroubledDebtRestructuringsThatWereOnNonAccrualStatus	20	loan
CY2021Q4	fnlc	Financing Receivable Loans Classified As Troubled Debt Restructurings That Were On Non Accrual Status FinancingReceivableLoansClassifiedAsTroubledDebtRestructuringsThatWereOnNonAccrualStatus	1894000	USD
CY2021Q4	fnlc	Loans Classified As Troubled Debt Restructurings That Are Involved In Foreclosure LoansClassifiedAsTroubledDebtRestructuringsThatAreInvolvedInForeclosure	0	USD
CY2021Q4	fnlc	Mortgage Loansin Processof Foreclosure Number MortgageLoansinProcessofForeclosureNumber	4	loan
CY2021Q4	us-gaap	Mortgage Loans In Process Of Foreclosure Amount MortgageLoansInProcessOfForeclosureAmount	367000	USD
CY2020Q4	fnlc	Mortgage Loansin Processof Foreclosure Number MortgageLoansinProcessofForeclosureNumber	11	loan
CY2020Q4	us-gaap	Mortgage Loans In Process Of Foreclosure Amount MortgageLoansInProcessOfForeclosureAmount	1109000	USD
CY2021Q4	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	576000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	462000	USD
CY2021Q4	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	14945000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	15791000	USD
CY2021Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	15521000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	16253000	USD
CY2021Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	15521000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	16253000	USD
CY2021	fnlc	Allowancefor Loanand Lease Losses Related Loans Percentage AllowanceforLoanandLeaseLossesRelatedLoansPercentage	0.0069
CY2020	fnlc	Allowancefor Loanand Lease Losses Related Loans Percentage AllowanceforLoanandLeaseLossesRelatedLoansPercentage	0.0080
CY2021	fnlc	Allowancefor Loanand Lease Losses Related Loans Period Increase Decrease AllowanceforLoanandLeaseLossesRelatedLoansPeriodIncreaseDecrease	-488000	USD
CY2021Q4	fnlc	Allowancefor Loan Lossesof Total Loans Percentage AllowanceforLoanLossesofTotalLoansPercentage	0.0094
CY2020Q4	fnlc	Allowancefor Loan Lossesof Total Loans Percentage AllowanceforLoanLossesofTotalLoansPercentage	0.0110
CY2021Q4	fnlc	Allowance For Loan Losses Of Loans Excluding Ppp Loans Percentage AllowanceForLoanLossesOfLoansExcludingPPPLoansPercentage	0.0095
CY2021Q4	fnlc	Loansand Leases Receivable Commercial Numberof Loan Classes LoansandLeasesReceivableCommercialNumberofLoanClasses	3	loan_class
CY2021Q4	fnlc	Commercial Real Estate Loans Maximum Loan To Value CommercialRealEstateLoansMaximumLoanToValue	0.80
CY2021Q4	fnlc	Loansand Leases Receivable Residential Numberof Loan Classes LoansandLeasesReceivableResidentialNumberofLoanClasses	2	loan_class
CY2021Q4	fnlc	Construction Loans Actual Loan Portfolio To Company Capital ConstructionLoansActualLoanPortfolioToCompanyCapital	0.482
CY2021Q4	fnlc	Construction Loan Portfolio Maximum To Company Capital ConstructionLoanPortfolioMaximumToCompanyCapital	1.000
CY2021Q4	fnlc	Construction And Non Owner Occupied Commercial Real Estate Loans Portfolio To Company Capital ConstructionAndNonOwnerOccupiedCommercialRealEstateLoansPortfolioToCompanyCapital	2.030
CY2021Q4	fnlc	Construction And Non Owner Occupied Commercial Real Estate Loans Maximum Loan Portfolio To Company Capital ConstructionAndNonOwnerOccupiedCommercialRealEstateLoansMaximumLoanPortfolioToCompanyCapital	3.000
CY2021Q4	fnlc	Outstanding Loans And Commitments Subject By Independent Consulting Firm OutstandingLoansAndCommitmentsSubjectByIndependentConsultingFirm	0.60
CY2021Q4	fnlc	Commercial And Municipal Risk Rated Loans Receivable CommercialAndMunicipalRiskRatedLoansReceivable	968495000	USD
CY2020Q4	fnlc	Commercial And Municipal Risk Rated Loans Receivable CommercialAndMunicipalRiskRatedLoansReceivable	827484000	USD
CY2021Q4	fnlc	Loansand Leases Receivable Residential Numberof Loan Classes LoansandLeasesReceivableResidentialNumberofLoanClasses	2	loan_class
CY2021Q4	fnlc	Residential Loans Typical Loan To Value Range Low ResidentialLoansTypicalLoanToValueRangeLow	0.75
CY2021Q4	fnlc	Residential Loans Typical Loan To Value ResidentialLoansTypicalLoanToValue	0.80
CY2021Q4	fnlc	Collateralized Consumer Loans To Individuals Loan To Value CollateralizedConsumerLoansToIndividualsLoanToValue	0.80
CY2021Q4	fnlc	Collateralized Consumer Loans To Individuals Loan To Value Maximum Range High CollateralizedConsumerLoansToIndividualsLoanToValueMaximumRangeHigh	0.90
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	16253000	USD
CY2021	us-gaap	Allowance For Loan And Lease Losses Write Offs AllowanceForLoanAndLeaseLossesWriteOffs	748000	USD
CY2021	us-gaap	Allowance For Loan And Lease Loss Recovery Of Bad Debts AllowanceForLoanAndLeaseLossRecoveryOfBadDebts	391000	USD
CY2021	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	-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	Notes Receivable Gross NotesReceivableGross	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
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	11639000	USD
CY2020	us-gaap	Allowance For Loan And Lease Losses Write Offs AllowanceForLoanAndLeaseLossesWriteOffs	1661000	USD
CY2020	us-gaap	Allowance For Loan And Lease Loss Recovery Of Bad Debts AllowanceForLoanAndLeaseLossRecoveryOfBadDebts	225000	USD
CY2020	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	6050000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	16253000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	462000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	15791000	USD
CY2020Q4	us-gaap	Notes Receivable Gross NotesReceivableGross	1476761000	USD
CY2020Q4	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	16039000	USD
CY2020Q4	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	1460722000	USD
CY2018Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	11232000	USD
CY2019	us-gaap	Allowance For Loan And Lease Losses Write Offs AllowanceForLoanAndLeaseLossesWriteOffs	1120000	USD
CY2019	us-gaap	Allowance For Loan And Lease Loss Recovery Of Bad Debts AllowanceForLoanAndLeaseLossRecoveryOfBadDebts	277000	USD
CY2019	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	1250000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	11639000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	2213000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	9426000	USD
CY2019Q4	us-gaap	Notes Receivable Gross NotesReceivableGross	1297075000	USD
CY2019Q4	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	29274000	USD
CY2019Q4	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	1267801000	USD
CY2021Q4	fnlc	Property Plant And Equipment And Operating Lease Right Of Use Asset Before Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndOperatingLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization	50439000	USD
CY2020Q4	fnlc	Property Plant And Equipment And Operating Lease Right Of Use Asset Before Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndOperatingLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization	47833000	USD
CY2021Q4	fnlc	Property Plant And Equipment And Operating Lease Right Of Use Asset Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndOperatingLeaseRightOfUseAssetAccumulatedDepreciationAndAmortization	21490000	USD
CY2020Q4	fnlc	Property Plant And Equipment And Operating Lease Right Of Use Asset Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndOperatingLeaseRightOfUseAssetAccumulatedDepreciationAndAmortization	20582000	USD
CY2021Q4	fnlc	Property Plant And Equipment And Operating Lease Right Of Use Asset Net Of Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndOperatingLeaseRightOfUseAssetNetOfAccumulatedDepreciationAndAmortization	28949000	USD
CY2020Q4	fnlc	Property Plant And Equipment And Operating Lease Right Of Use Asset Net Of Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndOperatingLeaseRightOfUseAssetNetOfAccumulatedDepreciationAndAmortization	27251000	USD
CY2021	us-gaap	Lease Cost LeaseCost	34000	USD
CY2020	us-gaap	Lease Cost LeaseCost	0	USD
CY2019	us-gaap	Lease Cost LeaseCost	0	USD
CY2021Q4	us-gaap	Lessor Operating Lease Payments To Be Received Next Twelve Months LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths	129000	USD
CY2021Q4	us-gaap	Lessor Operating Lease Payments To Be Received Two Years LessorOperatingLeasePaymentsToBeReceivedTwoYears	45000	USD
CY2021Q4	us-gaap	Lessor Operating Lease Payments To Be Received Three Years LessorOperatingLeasePaymentsToBeReceivedThreeYears	20000	USD
CY2021Q4	us-gaap	Lessor Operating Lease Payments To Be Received Four Years LessorOperatingLeasePaymentsToBeReceivedFourYears	4000	USD
CY2021Q4	us-gaap	Lessor Operating Lease Payments To Be Received Five Years LessorOperatingLeasePaymentsToBeReceivedFiveYears	4000	USD
CY2021Q4	us-gaap	Lessor Operating Lease Payments To Be Received Thereafter LessorOperatingLeasePaymentsToBeReceivedThereafter	19000	USD
CY2021Q4	us-gaap	Lessor Operating Lease Payments To Be Received LessorOperatingLeasePaymentsToBeReceived	221000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Term Of Contract LesseeOperatingLeaseTermOfContract	P5Y
CY2021Q4	us-gaap	Lessee Operating Lease Discount Rate LesseeOperatingLeaseDiscountRate	0.0125
CY2021Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	822000	USD
CY2020Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	511000	USD
CY2021Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	822000	USD
CY2020Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	511000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due After Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	459000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	938000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	116000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	97000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	97000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	97000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	97000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	91000	USD
CY2021Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	822000	USD
CY2021Q4	us-gaap	Real Estate Acquired Through Foreclosure RealEstateAcquiredThroughForeclosure	0	USD
CY2020Q4	us-gaap	Real Estate Acquired Through Foreclosure RealEstateAcquiredThroughForeclosure	908000	USD
CY2020Q4	us-gaap	Real Estate Owned Valuation Allowance RealEstateOwnedValuationAllowance	45000	USD
CY2019Q4	us-gaap	Real Estate Owned Valuation Allowance RealEstateOwnedValuationAllowance	0	USD
CY2018Q4	us-gaap	Real Estate Owned Valuation Allowance RealEstateOwnedValuationAllowance	0	USD
CY2021	us-gaap	Real Estate Owned Valuation Allowance Amounts Applied RealEstateOwnedValuationAllowanceAmountsApplied	45000	USD
CY2020	us-gaap	Real Estate Owned Valuation Allowance Amounts Applied RealEstateOwnedValuationAllowanceAmountsApplied	0	USD
CY2019	us-gaap	Real Estate Owned Valuation Allowance Amounts Applied RealEstateOwnedValuationAllowanceAmountsApplied	0	USD
CY2021	us-gaap	Federal Income Tax Expense Benefit Continuing Operations FederalIncomeTaxExpenseBenefitContinuingOperations	7057000	USD
CY2021	us-gaap	Real Estate Owned Valuation Allowance Provision1 RealEstateOwnedValuationAllowanceProvision1	0	USD
CY2020	us-gaap	Real Estate Owned Valuation Allowance Provision1 RealEstateOwnedValuationAllowanceProvision1	45000	USD
CY2019	us-gaap	Real Estate Owned Valuation Allowance Provision1 RealEstateOwnedValuationAllowanceProvision1	0	USD
CY2021Q4	us-gaap	Real Estate Owned Valuation Allowance RealEstateOwnedValuationAllowance	0	USD
CY2020Q4	us-gaap	Real Estate Owned Valuation Allowance RealEstateOwnedValuationAllowance	45000	USD
CY2019Q4	us-gaap	Real Estate Owned Valuation Allowance RealEstateOwnedValuationAllowance	0	USD
CY2020	us-gaap	Federal Income Tax Expense Benefit Continuing Operations FederalIncomeTaxExpenseBenefitContinuingOperations	4661000	USD
CY2021	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	6058000	USD
CY2020	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	4923000	USD
CY2019	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	3978000	USD
CY2021	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	999000	USD
CY2020	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-262000	USD
CY2019	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	336000	USD
CY2019	us-gaap	Federal Income Tax Expense Benefit Continuing Operations FederalIncomeTaxExpenseBenefitContinuingOperations	4314000	USD
CY2021	us-gaap	State And Local Income Tax Expense Benefit Continuing Operations StateAndLocalIncomeTaxExpenseBenefitContinuingOperations	587000	USD
CY2020	us-gaap	State And Local Income Tax Expense Benefit Continuing Operations StateAndLocalIncomeTaxExpenseBenefitContinuingOperations	460000	USD
CY2019	us-gaap	State And Local Income Tax Expense Benefit Continuing Operations StateAndLocalIncomeTaxExpenseBenefitContinuingOperations	421000	USD
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	7644000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	5121000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	4735000	USD
CY2021	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	9222000	USD
CY2020	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	6773000	USD
CY2019	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	6355000	USD
CY2021	us-gaap	Income Tax Reconciliation Tax Exempt Income IncomeTaxReconciliationTaxExemptIncome	1833000	USD
CY2020	us-gaap	Income Tax Reconciliation Tax Exempt Income IncomeTaxReconciliationTaxExemptIncome	1808000	USD
CY2019	us-gaap	Income Tax Reconciliation Tax Exempt Income IncomeTaxReconciliationTaxExemptIncome	1749000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Provision For Loan Losses DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsProvisionForLoanLosses	3259000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Provision For Loan Losses DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsProvisionForLoanLosses	3413000	USD
CY2020Q4	fnlc	Deferred Tax Assets Other Real Estate Owned DeferredTaxAssetsOtherRealEstateOwned	9000	USD
CY2021Q4	fnlc	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Postretirement Benefits And Pension DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsPostretirementBenefitsAndPension	887000	USD
CY2020Q4	fnlc	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Postretirement Benefits And Pension DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsPostretirementBenefitsAndPension	948000	USD
CY2021Q4	fnlc	Deferred Tax Assets Other Real Estate Owned DeferredTaxAssetsOtherRealEstateOwned	0	USD
CY2021	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	444000	USD
CY2020	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	348000	USD
CY2019	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	332000	USD
CY2021	us-gaap	Income Tax Reconciliation Nondeductible Expense Share Based Compensation Cost IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost	-41000	USD
CY2020	us-gaap	Income Tax Reconciliation Nondeductible Expense Share Based Compensation Cost IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost	-43000	USD
CY2019	us-gaap	Income Tax Reconciliation Nondeductible Expense Share Based Compensation Cost IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost	-45000	USD
CY2021	us-gaap	Income Tax Reconciliation Tax Credits IncomeTaxReconciliationTaxCredits	150000	USD
CY2020	us-gaap	Income Tax Reconciliation Tax Credits IncomeTaxReconciliationTaxCredits	144000	USD
CY2019	us-gaap	Income Tax Reconciliation Tax Credits IncomeTaxReconciliationTaxCredits	85000	USD
CY2021	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	2000	USD
CY2020	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	-5000	USD
CY2019	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	-73000	USD
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	7644000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	5121000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	4735000	USD
CY2021Q4	us-gaap	Deferred Tax Liabilities Financing Arrangements DeferredTaxLiabilitiesFinancingArrangements	2055000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Financing Arrangements DeferredTaxLiabilitiesFinancingArrangements	1894000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Unrealized Losses On Availablefor Sale Securities Gross DeferredTaxAssetsUnrealizedLossesOnAvailableforSaleSecuritiesGross	457000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Unrealized Losses On Availablefor Sale Securities Gross DeferredTaxAssetsUnrealizedLossesOnAvailableforSaleSecuritiesGross	0	USD
CY2021Q4	us-gaap	Deferred Tax Assets Derivative Instruments DeferredTaxAssetsDerivativeInstruments	544000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Derivative Instruments DeferredTaxAssetsDerivativeInstruments	1865000	USD
CY2021Q4	fnlc	Deferred Tax Asset Securities Transferedfrom Af Sto Htm DeferredTaxAssetSecuritiesTransferedfromAFStoHTM	23000	USD
CY2020Q4	fnlc	Deferred Tax Asset Securities Transferedfrom Af Sto Htm DeferredTaxAssetSecuritiesTransferedfromAFStoHTM	35000	USD
CY2021Q4	fnlc	Deferred Tax Asset Restricted Stock Grants DeferredTaxAssetRestrictedStockGrants	308000	USD
CY2020Q4	fnlc	Deferred Tax Asset Restricted Stock Grants DeferredTaxAssetRestrictedStockGrants	270000	USD
CY2021Q4	fnlc	Deferred Tax Asset Intangible Liabilities DeferredTaxAssetIntangibleLiabilities	29000	USD
CY2020Q4	fnlc	Deferred Tax Asset Intangible Liabilities DeferredTaxAssetIntangibleLiabilities	24000	USD
CY2021Q4	fnlc	Deferred Tax Assets Investmentin Limited Partnership DeferredTaxAssetsInvestmentinLimitedPartnership	79000	USD
CY2020Q4	fnlc	Deferred Tax Assets Investmentin Limited Partnership DeferredTaxAssetsInvestmentinLimitedPartnership	82000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	35000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	87000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	5621000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	6733000	USD
CY2021Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	2334000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	2013000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Accumulated Gross Unrealized Gain Loss Before Tax DebtSecuritiesAvailableForSaleAccumulatedGrossUnrealizedGainLossBeforeTax	0	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Accumulated Gross Unrealized Gain Loss Before Tax DebtSecuritiesAvailableForSaleAccumulatedGrossUnrealizedGainLossBeforeTax	1332000	USD
CY2021Q4	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets Goodwill DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsGoodwill	214000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets Goodwill DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsGoodwill	161000	USD
CY2021Q4	us-gaap	Deferred Tax Liabilities Mortgage Servicing Rights DeferredTaxLiabilitiesMortgageServicingRights	561000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Mortgage Servicing Rights DeferredTaxLiabilitiesMortgageServicingRights	411000	USD
CY2021Q4	us-gaap	Deferred Tax Liabilities Derivatives DeferredTaxLiabilitiesDerivatives	544000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Derivatives DeferredTaxLiabilitiesDerivatives	554000	USD
CY2021Q4	us-gaap	Deferred Tax Liabilities Prepaid Expenses DeferredTaxLiabilitiesPrepaidExpenses	295000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Prepaid Expenses DeferredTaxLiabilitiesPrepaidExpenses	195000	USD
CY2021Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	6003000	USD
CY2020Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	6560000	USD
CY2021Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	382000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	173000	USD
CY2021Q4	fnlc	Limited Partnerships Held As Investments LimitedPartnershipsHeldAsInvestments	4	limited_partnership
CY2020Q4	fnlc	Limited Partnerships Held As Investments LimitedPartnershipsHeldAsInvestments	4	limited_partnership
CY2021	us-gaap	Income Tax Reconciliation Tax Credits Investment IncomeTaxReconciliationTaxCreditsInvestment	354000	USD
CY2020	us-gaap	Income Tax Reconciliation Tax Credits Investment IncomeTaxReconciliationTaxCreditsInvestment	351000	USD
CY2021	us-gaap	Income Tax Reconciliation Nondeductible Expense Amortization IncomeTaxReconciliationNondeductibleExpenseAmortization	309000	USD
CY2020	us-gaap	Income Tax Reconciliation Nondeductible Expense Amortization IncomeTaxReconciliationNondeductibleExpenseAmortization	311000	USD
CY2021Q4	us-gaap	Limited Partners Capital Account LimitedPartnersCapitalAccount	1753000	USD
CY2020Q4	us-gaap	Limited Partners Capital Account LimitedPartnersCapitalAccount	1734000	USD
CY2021Q4	us-gaap	Time Deposits Less Than100000 TimeDepositsLessThan100000	252568000	USD
CY2020Q4	us-gaap	Time Deposits Less Than100000 TimeDepositsLessThan100000	246875000	USD
CY2021Q4	fnlc	Time Deposits Greater Than100000 And Less Than250000 TimeDepositsGreaterThan100000AndLessThan250000	258211000	USD
CY2020Q4	fnlc	Time Deposits Greater Than100000 And Less Than250000 TimeDepositsGreaterThan100000AndLessThan250000	295672000	USD
CY2021Q4	fnlc	Time Deposits250000 Or More TimeDeposits250000OrMore	55426000	USD
CY2020Q4	fnlc	Time Deposits250000 Or More TimeDeposits250000OrMore	63038000	USD
CY2021Q4	fnlc	Credit Facility With Federal Reserve Bank Of Boston CreditFacilityWithFederalReserveBankOfBoston	139000000	USD
CY2021Q4	us-gaap	Time Deposits TimeDeposits	566205000	USD
CY2020Q4	us-gaap	Time Deposits TimeDeposits	605585000	USD
CY2021Q4	us-gaap	Time Deposit Maturities Year One TimeDepositMaturitiesYearOne	323832000	USD
CY2021Q4	us-gaap	Time Deposit Maturities Year Two TimeDepositMaturitiesYearTwo	87110000	USD
CY2021Q4	us-gaap	Time Deposit Maturities Year Three TimeDepositMaturitiesYearThree	74410000	USD
CY2021Q4	us-gaap	Time Deposit Maturities Year Four TimeDepositMaturitiesYearFour	34741000	USD
CY2021Q4	us-gaap	Time Deposit Maturities Year Five TimeDepositMaturitiesYearFive	45722000	USD
CY2021Q4	us-gaap	Time Deposit Maturities After Year Five TimeDepositMaturitiesAfterYearFive	390000	USD
CY2021Q4	us-gaap	Time Deposits TimeDeposits	566205000	USD
CY2021	us-gaap	Interest Expense Time Deposits100000 Or More InterestExpenseTimeDeposits100000OrMore	2462000	USD
CY2020	us-gaap	Interest Expense Time Deposits100000 Or More InterestExpenseTimeDeposits100000OrMore	5327000	USD
CY2019	us-gaap	Interest Expense Time Deposits100000 Or More InterestExpenseTimeDeposits100000OrMore	6060000	USD
CY2021Q4	fnlc	Line Of Credit With Correspondent Banks LineOfCreditWithCorrespondentBanks	76000000	USD
CY2020	us-gaap	Defined Contribution Plan Employer Matching Contribution Percent Of Match DefinedContributionPlanEmployerMatchingContributionPercentOfMatch	0.030
CY2020Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due From Two To Three Years Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueFromTwoToThreeYearsOfBalanceSheetDate	0	USD
CY2020	fnlc	Federal Home Loan Bank Advances Interest Rate Maturities Summary Duein Year Four FederalHomeLoanBankAdvancesInterestRateMaturitiesSummaryDueinYearFour	0
CY2020Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due From Three To Four Years Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueFromThreeToFourYearsOfBalanceSheetDate	98000	USD
CY2020Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due From Four To Five Years Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueFromFourToFiveYearsOfBalanceSheetDate	55000000	USD
CY2020	fnlc	Federal Home Loan Bank Advances Interest Rate Maturities Summary Due In Year Five And Thereafter FederalHomeLoanBankAdvancesInterestRateMaturitiesSummaryDueInYearFiveAndThereafter	0
CY2020Q4	fnlc	Federal Home Loan Bank Advance Maturity Year Five And Thereafter FederalHomeLoanBankAdvanceMaturityYearFiveAndThereafter	0	USD
CY2020Q4	us-gaap	Advances From Federal Home Loan Banks AdvancesFromFederalHomeLoanBanks	192698000	USD
CY2020Q4	us-gaap	Securities Sold Under Agreements To Repurchase SecuritiesSoldUnderAgreementsToRepurchase	69340000	USD
CY2020Q4	fnlc	Total Federal Home Loan Bank Advances Treasury Tax Notes And Repurchase Agreements TotalFederalHomeLoanBankAdvancesTreasuryTaxNotesAndRepurchaseAgreements	262038000	USD
CY2021	us-gaap	Deferred Compensation Arrangement With Individual Requisite Service Period1 DeferredCompensationArrangementWithIndividualRequisiteServicePeriod1	P3M
CY2021Q4	fnlc	Defined Contribution Plan Employer Maximum Percentage Match Of Employee Annual Salary DefinedContributionPlanEmployerMaximumPercentageMatchOfEmployeeAnnualSalary	0.030
CY2021Q4	fnlc	Defined Contribution Plan Employer Maximum Profit Sharing Contributions DefinedContributionPlanEmployerMaximumProfitSharingContributions	0.020
CY2020Q4	fnlc	Defined Contribution Plan Employer Maximum Profit Sharing Contributions DefinedContributionPlanEmployerMaximumProfitSharingContributions	0.020
CY2021	us-gaap	Defined Contribution Plan Employer Matching Contribution Percent Of Match DefinedContributionPlanEmployerMatchingContributionPercentOfMatch	0.030
CY2021Q4	fnlc	Line Of Credit With Correspondent Banks And Credit Facility With Federal Reserve Of Boston LineOfCreditWithCorrespondentBanksAndCreditFacilityWithFederalReserveOfBoston	0	USD
CY2021Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due Within One Year Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueWithinOneYearOfBalanceSheetDate	0	USD
CY2021	fnlc	Federal Home Loan Bank Advances Interest Rate Maturities Summary Duein Year Two FederalHomeLoanBankAdvancesInterestRateMaturitiesSummaryDueinYearTwo	0
CY2021Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due From One To Two Years Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueFromOneToTwoYearsOfBalanceSheetDate	0	USD
CY2021	fnlc	Federal Home Loan Bank Advances Interest Rate Maturities Summary Duein Year Three FederalHomeLoanBankAdvancesInterestRateMaturitiesSummaryDueinYearThree	0
CY2021Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due From Two To Three Years Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueFromTwoToThreeYearsOfBalanceSheetDate	90000	USD
CY2021Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due From Three To Four Years Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueFromThreeToFourYearsOfBalanceSheetDate	55000000	USD
CY2021	fnlc	Federal Home Loan Bank Advances Interest Rate Maturities Summary Due In Year Five And Thereafter FederalHomeLoanBankAdvancesInterestRateMaturitiesSummaryDueInYearFiveAndThereafter	0.0000
CY2021Q4	fnlc	Federal Home Loan Bank Advance Maturity Year Five And Thereafter FederalHomeLoanBankAdvanceMaturityYearFiveAndThereafter	0	USD
CY2021Q4	us-gaap	Advances From Federal Home Loan Banks AdvancesFromFederalHomeLoanBanks	55090000	USD
CY2021Q4	us-gaap	Securities Sold Under Agreements To Repurchase SecuritiesSoldUnderAgreementsToRepurchase	81252000	USD
CY2021Q4	fnlc	Total Federal Home Loan Bank Advances Treasury Tax Notes And Repurchase Agreements TotalFederalHomeLoanBankAdvancesTreasuryTaxNotesAndRepurchaseAgreements	136342000	USD
CY2020Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due Within One Year Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueWithinOneYearOfBalanceSheetDate	137600000	USD
CY2020	fnlc	Federal Home Loan Bank Advances Interest Rate Maturities Summary Duein Year Two FederalHomeLoanBankAdvancesInterestRateMaturitiesSummaryDueinYearTwo	0
CY2020Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due From One To Two Years Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueFromOneToTwoYearsOfBalanceSheetDate	0	USD
CY2020	fnlc	Federal Home Loan Bank Advances Interest Rate Maturities Summary Duein Year Three FederalHomeLoanBankAdvancesInterestRateMaturitiesSummaryDueinYearThree	0
CY2020	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	981000	USD
CY2019	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	575000	USD
CY2021	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	775000	USD
CY2021	fnlc	Post Employment Plan Supplemental Benefits Payment Period Upon Retirement Or Death PostEmploymentPlanSupplementalBenefitsPaymentPeriodUponRetirementOrDeath	P20Y
CY2021	us-gaap	Pension And Other Postretirement Benefit Expense PensionAndOtherPostretirementBenefitExpense	167000	USD
CY2020	us-gaap	Pension And Other Postretirement Benefit Expense PensionAndOtherPostretirementBenefitExpense	450000	USD
CY2019	us-gaap	Pension And Other Postretirement Benefit Expense PensionAndOtherPostretirementBenefitExpense	165000	USD
CY2021Q4	us-gaap	Defined Benefit Pension Plan Current And Noncurrent Liabilities DefinedBenefitPensionPlanCurrentAndNoncurrentLiabilities	2872000	USD
CY2020Q4	us-gaap	Defined Benefit Pension Plan Current And Noncurrent Liabilities DefinedBenefitPensionPlanCurrentAndNoncurrentLiabilities	2991000	USD
CY2021Q4	fnlc	Number Of Post Retirement Benefit Plans NumberOfPostRetirementBenefitPlans	2	postretirement_benefit_plan
CY2021Q4	fnlc	Post Retirement Benefit Plan Health Insurance Subsidy Range Minimum PostRetirementBenefitPlanHealthInsuranceSubsidyRangeMinimum	40	USD
CY2021Q4	fnlc	Post Retirement Benefit Plan Health Insurance Subsidy Range Maximum PostRetirementBenefitPlanHealthInsuranceSubsidyRangeMaximum	1200	USD
CY2020Q4	us-gaap	Defined Benefit Plan Benefit Obligation DefinedBenefitPlanBenefitObligation	1523000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Benefit Obligation DefinedBenefitPlanBenefitObligation	1581000	USD
CY2018Q4	us-gaap	Defined Benefit Plan Benefit Obligation DefinedBenefitPlanBenefitObligation	1599000	USD
CY2021	us-gaap	Defined Benefit Plan Interest Cost DefinedBenefitPlanInterestCost	29000	USD
CY2020	us-gaap	Defined Benefit Plan Interest Cost DefinedBenefitPlanInterestCost	46000	USD
CY2019	us-gaap	Defined Benefit Plan Interest Cost DefinedBenefitPlanInterestCost	66000	USD
CY2021	us-gaap	Defined Benefit Plan Benefit Obligation Benefits Paid DefinedBenefitPlanBenefitObligationBenefitsPaid	93000	USD
CY2020	us-gaap	Defined Benefit Plan Benefit Obligation Benefits Paid DefinedBenefitPlanBenefitObligationBenefitsPaid	97000	USD
CY2019	us-gaap	Defined Benefit Plan Benefit Obligation Benefits Paid DefinedBenefitPlanBenefitObligationBenefitsPaid	97000	USD
CY2021Q4	fnlc	Actuarialgainloss Actuarialgainloss	-106000	USD
CY2020Q4	fnlc	Actuarialgainloss Actuarialgainloss	-7000	USD
CY2019Q4	fnlc	Actuarialgainloss Actuarialgainloss	13000	USD
CY2021Q4	us-gaap	Defined Benefit Plan Benefit Obligation DefinedBenefitPlanBenefitObligation	1353000	USD
CY2020Q4	us-gaap	Defined Benefit Plan Benefit Obligation DefinedBenefitPlanBenefitObligation	1523000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Benefit Obligation DefinedBenefitPlanBenefitObligation	1581000	USD
CY2021Q4	us-gaap	Defined Benefit Plan Benefit Obligation DefinedBenefitPlanBenefitObligation	1353000	USD
CY2020Q4	us-gaap	Defined Benefit Plan Benefit Obligation DefinedBenefitPlanBenefitObligation	1523000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Benefit Obligation DefinedBenefitPlanBenefitObligation	1581000	USD
CY2021	us-gaap	Defined Benefit Plan Actuarial Gain Loss DefinedBenefitPlanActuarialGainLoss	133000	USD
CY2020	us-gaap	Defined Benefit Plan Actuarial Gain Loss DefinedBenefitPlanActuarialGainLoss	35000	USD
CY2019	us-gaap	Defined Benefit Plan Actuarial Gain Loss DefinedBenefitPlanActuarialGainLoss	31000	USD
CY2021Q4	us-gaap	Defined Benefit Plan Funded Status Of Plan DefinedBenefitPlanFundedStatusOfPlan	-1486000	USD
CY2020Q4	us-gaap	Defined Benefit Plan Funded Status Of Plan DefinedBenefitPlanFundedStatusOfPlan	-1558000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Funded Status Of Plan DefinedBenefitPlanFundedStatusOfPlan	-1612000	USD
CY2021Q4	fnlc	Weighted Average Discount Rate As Of December31 WeightedAverageDiscountRateAsOfDecember31	0.0250
CY2020Q4	fnlc	Weighted Average Discount Rate As Of December31 WeightedAverageDiscountRateAsOfDecember31	0.0200
CY2019Q4	fnlc	Weighted Average Discount Rate As Of December31 WeightedAverageDiscountRateAsOfDecember31	0.0300
CY2021Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Year Two DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo	87000	USD
CY2021	us-gaap	Defined Benefit Plan Interest Cost DefinedBenefitPlanInterestCost	29000	USD
CY2020	us-gaap	Defined Benefit Plan Interest Cost DefinedBenefitPlanInterestCost	46000	USD
CY2019	us-gaap	Defined Benefit Plan Interest Cost DefinedBenefitPlanInterestCost	66000	USD
CY2021	fnlc	Defined Benefit Plan Other Settlement Expense DefinedBenefitPlanOtherSettlementExpense	9000	USD
CY2020	fnlc	Defined Benefit Plan Other Settlement Expense DefinedBenefitPlanOtherSettlementExpense	2000	USD
CY2019	fnlc	Defined Benefit Plan Other Settlement Expense DefinedBenefitPlanOtherSettlementExpense	2000	USD
CY2021	us-gaap	Defined Benefit Plan Net Periodic Benefit Cost DefinedBenefitPlanNetPeriodicBenefitCost	20000	USD
CY2020	us-gaap	Defined Benefit Plan Net Periodic Benefit Cost DefinedBenefitPlanNetPeriodicBenefitCost	44000	USD
CY2019	us-gaap	Defined Benefit Plan Net Periodic Benefit Cost DefinedBenefitPlanNetPeriodicBenefitCost	64000	USD
CY2021	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Discount Rate DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate	0.0200
CY2020	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Discount Rate DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate	0.0300
CY2019	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Discount Rate DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate	0.0425
CY2021Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Next Twelve Months DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths	87000	USD
CY2021Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Year Three DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree	96000	USD
CY2021Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Year Four DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour	95000	USD
CY2021Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Year Five DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive	93000	USD
CY2021Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Five Fiscal Years Thereafter DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter	425000	USD
CY2021Q4	us-gaap	Defined Benefit Plan Expected Future Employer Contributions Remainder Of Fiscal Year DefinedBenefitPlanExpectedFutureEmployerContributionsRemainderOfFiscalYear	33000	USD
CY2021Q4	us-gaap	Defined Benefit Plan Accumulated Other Comprehensive Income Net Gains Losses Before Tax DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax	133000	USD
CY2020Q4	us-gaap	Defined Benefit Plan Accumulated Other Comprehensive Income Net Gains Losses Before Tax DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax	35000	USD
CY2021Q4	us-gaap	Defined Benefit Plan Expected Amortization Of Gain Loss Next Fiscal Year DefinedBenefitPlanExpectedAmortizationOfGainLossNextFiscalYear	0	USD
CY2021Q4	fnlc	Accumulated Other Comprehensive Income Defined Benefit Plans Tax Deferred Tax Benefit AccumulatedOtherComprehensiveIncomeDefinedBenefitPlansTaxDeferredTaxBenefit	-28000	USD
CY2020Q4	fnlc	Accumulated Other Comprehensive Income Defined Benefit Plans Tax Deferred Tax Benefit AccumulatedOtherComprehensiveIncomeDefinedBenefitPlansTaxDeferredTaxBenefit	-7000	USD
CY2021	fnlc	Defined Benefit Plan Future Deferred Tax Benefit DefinedBenefitPlanFutureDeferredTaxBenefit	0	USD
CY2021Q4	us-gaap	Accumulated Other Comprehensive Income Loss Defined Benefit Pension And Other Postretirement Plans Net Of Tax AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax	-105000	USD
CY2020Q4	us-gaap	Accumulated Other Comprehensive Income Loss Defined Benefit Pension And Other Postretirement Plans Net Of Tax AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax	-28000	USD
CY2021Q4	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
CY2021Q4	fnlc	Number Of Shares Issued Under Employee Savings And Investment Plan NumberOfSharesIssuedUnderEmployeeSavingsAndInvestmentPlan	79203	shares
CY2021Q4	fnlc	Number Of Shares Available For Future Use Under Employee Savings And Investment Plan NumberOfSharesAvailableForFutureUseUnderEmployeeSavingsAndInvestmentPlan	170797	shares
CY2015Q4	fnlc	Number Of Shares Available For Grant Under Employee Savings And Investment Plan NumberOfSharesAvailableForGrantUnderEmployeeSavingsAndInvestmentPlan	700000	shares
CY2021	us-gaap	Stock Issued During Period Shares Employee Stock Purchase Plans StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans	12267	shares
CY2020	us-gaap	Stock Issued During Period Shares Employee Stock Purchase Plans StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans	14117	shares
CY2019	us-gaap	Stock Issued During Period Shares Employee Stock Purchase Plans StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans	13408	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	305362	shares
CY2021	fnlc	Stock Remainingunder Plan Shares Dividend Reinvestment Plan StockRemainingunderPlanSharesDividendReinvestmentPlan	294638	shares
CY2021	us-gaap	Stock Issued During Period Shares Dividend Reinvestment Plan StockIssuedDuringPeriodSharesDividendReinvestmentPlan	11772	shares
CY2020	us-gaap	Stock Issued During Period Shares Dividend Reinvestment Plan StockIssuedDuringPeriodSharesDividendReinvestmentPlan	15064	shares
CY2019	us-gaap	Stock Issued During Period Shares Dividend Reinvestment Plan StockIssuedDuringPeriodSharesDividendReinvestmentPlan	11242	shares
CY2021	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	2135000	USD
CY2021	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	856000	USD
CY2021Q4	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized	671000	USD
CY2020	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	652000	USD
CY2020Q4	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized	694000	USD
CY2021	us-gaap	Net Income Loss NetIncomeLoss	36269000	USD
CY2021	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	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
CY2020	us-gaap	Net Income Loss NetIncomeLoss	27129000	USD
CY2020	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	27129000	USD
CY2020	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	10858606	shares
CY2020	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.50
CY2020	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	74212	shares
CY2020	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	27129000	USD
CY2020	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	10932818	shares
CY2020	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.48
CY2019	us-gaap	Net Income Loss NetIncomeLoss	25525000	USD
CY2019	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	25525000	USD
CY2019	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	10815718	shares
CY2019	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.36
CY2019	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	73591	shares
CY2019	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	25525000	USD
CY2019	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	10889309	shares
CY2019	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.34
CY2021Q4	fnlc	Retained Earnings From Prior Two Years Available For Dividends RetainedEarningsFromPriorTwoYearsAvailableForDividends	38234000	USD
CY2020Q4	fnlc	Retained Earnings From Prior Two Years Available For Dividends RetainedEarningsFromPriorTwoYearsAvailableForDividends	38234000	USD
CY2021Q4	fnlc	Capital Conservation Buffer CapitalConservationBuffer	0.0627
CY2021Q4	fnlc	Capital Conservation Buffer Phasein Minimum CapitalConservationBufferPhaseinMinimum	0.025
CY2021Q4	us-gaap	Fair Value Disclosure Offbalance Sheet Risks Amount Liability FairValueDisclosureOffbalanceSheetRisksAmountLiability	363904000	USD
CY2020Q4	us-gaap	Fair Value Disclosure Offbalance Sheet Risks Amount Liability FairValueDisclosureOffbalanceSheetRisksAmountLiability	231756000	USD
CY2021	us-gaap	Servicing Asset At Amortized Cost Other Than Temporary Impairments ServicingAssetAtAmortizedCostOtherThanTemporaryImpairments	26000	USD
CY2020	us-gaap	Servicing Asset At Amortized Cost Other Than Temporary Impairments ServicingAssetAtAmortizedCostOtherThanTemporaryImpairments	358000	USD
CY2020Q4	us-gaap	Real Estate Owned Valuation Allowance RealEstateOwnedValuationAllowance	45000	USD
CY2021Q4	us-gaap	Real Estate Owned Valuation Allowance RealEstateOwnedValuationAllowance	0	USD
CY2021Q4	fnlc	Impaired Financing Receivable Related Allowance Measuredat Fair Value ImpairedFinancingReceivableRelatedAllowanceMeasuredatFairValue	441000	USD
CY2020Q4	fnlc	Impaired Financing Receivable Related Allowance Measuredat Fair Value ImpairedFinancingReceivableRelatedAllowanceMeasuredatFairValue	304000	USD
CY2021	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	1181000	USD
CY2020	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	983000	USD
CY2019	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	1174000	USD
CY2021	fnlc	Atm And Interchange Expense AtmAndInterchangeExpense	1446000	USD
CY2020	fnlc	Atm And Interchange Expense AtmAndInterchangeExpense	1253000	USD
CY2019	fnlc	Atm And Interchange Expense AtmAndInterchangeExpense	1176000	USD
CY2021	fnlc	Swap Termination Expense SwapTerminationExpense	0	USD
CY2020	fnlc	Swap Termination Expense SwapTerminationExpense	1756000	USD
CY2019	fnlc	Swap Termination Expense SwapTerminationExpense	0	USD
CY2021	fnlc	Other Loan Expenses OtherLoanExpenses	2198000	USD
CY2020	fnlc	Other Loan Expenses OtherLoanExpenses	0	USD
CY2019	fnlc	Other Loan Expenses OtherLoanExpenses	0	USD
CY2021	us-gaap	Loss Contingency Disclosures LossContingencyDisclosures	Legal ContingenciesVarious 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.
CY2021	us-gaap	Prior Period Reclassification Adjustment Description PriorPeriodReclassificationAdjustmentDescription	ReclassificationsCertain 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.
CY2020Q1	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	21117000	USD
CY2020Q2	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	22143000	USD
CY2020Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	22742000	USD
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	26212000	USD
CY2021Q1	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	20029000	USD
CY2021Q2	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	27092000	USD
CY2021Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	27126000	USD
CY2021Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	20634000	USD
CY2020Q1	us-gaap	Interest Bearing Deposits In Banks InterestBearingDepositsInBanks	6047000	USD
CY2020Q2	us-gaap	Interest Bearing Deposits In Banks InterestBearingDepositsInBanks	21907000	USD
CY2020Q3	us-gaap	Interest Bearing Deposits In Banks InterestBearingDepositsInBanks	48111000	USD
CY2020Q4	us-gaap	Interest Bearing Deposits In Banks InterestBearingDepositsInBanks	56151000	USD
CY2021Q1	us-gaap	Interest Bearing Deposits In Banks InterestBearingDepositsInBanks	104602000	USD
CY2021Q2	us-gaap	Interest Bearing Deposits In Banks InterestBearingDepositsInBanks	42215000	USD
CY2021Q3	us-gaap	Interest Bearing Deposits In Banks InterestBearingDepositsInBanks	93779000	USD
CY2021Q4	us-gaap	Interest Bearing Deposits In Banks InterestBearingDepositsInBanks	66678000	USD
CY2020Q1	us-gaap	Investments Investments	654520000	USD
CY2020Q2	us-gaap	Investments Investments	653462000	USD
CY2020Q3	us-gaap	Investments Investments	672102000	USD
CY2020Q4	us-gaap	Investments Investments	678989000	USD
CY2021Q1	us-gaap	Investments Investments	679889000	USD
CY2021Q2	us-gaap	Investments Investments	682428000	USD
CY2021Q3	us-gaap	Investments Investments	684923000	USD
CY2021Q4	us-gaap	Investments Investments	690606000	USD
CY2020Q1	fnlc	Federal Home Loan Bank And Federal Reserve Bank Stock At Cost FederalHomeLoanBankAndFederalReserveBankStockAtCost	9994000	USD
CY2020Q2	fnlc	Federal Home Loan Bank And Federal Reserve Bank Stock At Cost FederalHomeLoanBankAndFederalReserveBankStockAtCost	10545000	USD
CY2020Q3	fnlc	Federal Home Loan Bank And Federal Reserve Bank Stock At Cost FederalHomeLoanBankAndFederalReserveBankStockAtCost	10545000	USD
CY2020Q4	fnlc	Federal Home Loan Bank And Federal Reserve Bank Stock At Cost FederalHomeLoanBankAndFederalReserveBankStockAtCost	10545000	USD
CY2021Q1	fnlc	Federal Home Loan Bank And Federal Reserve Bank Stock At Cost FederalHomeLoanBankAndFederalReserveBankStockAtCost	10105000	USD
CY2021Q2	fnlc	Federal Home Loan Bank And Federal Reserve Bank Stock At Cost FederalHomeLoanBankAndFederalReserveBankStockAtCost	8839000	USD
CY2021Q3	fnlc	Federal Home Loan Bank And Federal Reserve Bank Stock At Cost FederalHomeLoanBankAndFederalReserveBankStockAtCost	8839000	USD
CY2020Q2	fnlc	Loans And Lease Receivable Net LoansAndLeaseReceivableNet	1442463000	USD
CY2020Q3	fnlc	Loans And Lease Receivable Net LoansAndLeaseReceivableNet	1427662000	USD
CY2021Q4	fnlc	Federal Home Loan Bank And Federal Reserve Bank Stock At Cost FederalHomeLoanBankAndFederalReserveBankStockAtCost	5365000	USD
CY2020Q1	fnlc	Loans And Lease Receivable Net LoansAndLeaseReceivableNet	1332911000	USD
CY2020Q4	fnlc	Loans And Lease Receivable Net LoansAndLeaseReceivableNet	1466363000	USD
CY2021Q1	fnlc	Loans And Lease Receivable Net LoansAndLeaseReceivableNet	1503700000	USD
CY2021Q2	fnlc	Loans And Lease Receivable Net LoansAndLeaseReceivableNet	1572377000	USD
CY2021Q3	fnlc	Loans And Lease Receivable Net LoansAndLeaseReceivableNet	1601142000	USD
CY2021Q4	fnlc	Loans And Lease Receivable Net LoansAndLeaseReceivableNet	1632963000	USD
CY2020Q1	us-gaap	Other Assets Miscellaneous OtherAssetsMiscellaneous	111807000	USD
CY2020Q2	us-gaap	Other Assets Miscellaneous OtherAssetsMiscellaneous	116604000	USD
CY2020Q3	us-gaap	Other Assets Miscellaneous OtherAssetsMiscellaneous	115464000	USD
CY2020Q4	us-gaap	Other Assets Miscellaneous OtherAssetsMiscellaneous	122976000	USD
CY2021Q1	us-gaap	Other Assets Miscellaneous OtherAssetsMiscellaneous	118543000	USD
CY2021Q2	us-gaap	Other Assets Miscellaneous OtherAssetsMiscellaneous	117492000	USD
CY2021Q3	us-gaap	Other Assets Miscellaneous OtherAssetsMiscellaneous	113782000	USD
CY2021Q4	us-gaap	Deposits Deposits	2123297000	USD
CY2021Q4	us-gaap	Other Assets Miscellaneous OtherAssetsMiscellaneous	110853000	USD
CY2020Q1	us-gaap	Assets Assets	2136396000	USD
CY2020Q2	us-gaap	Assets Assets	2267124000	USD
CY2020Q3	us-gaap	Assets Assets	2296626000	USD
CY2020Q4	us-gaap	Assets Assets	2361236000	USD
CY2021Q1	us-gaap	Assets Assets	2436868000	USD
CY2021Q2	us-gaap	Assets Assets	2450443000	USD
CY2021Q3	us-gaap	Assets Assets	2529591000	USD
CY2021Q4	us-gaap	Assets Assets	2527099000	USD
CY2020Q1	us-gaap	Deposits Deposits	1644612000	USD
CY2020Q2	us-gaap	Deposits Deposits	1740121000	USD
CY2020Q3	us-gaap	Deposits Deposits	1763059000	USD
CY2020Q4	us-gaap	Deposits Deposits	1844611000	USD
CY2021Q1	us-gaap	Deposits Deposits	1953557000	USD
CY2021Q2	us-gaap	Deposits Deposits	1961321000	USD
CY2021Q3	us-gaap	Deposits Deposits	2033213000	USD
CY2020Q1	us-gaap	Stockholders Equity StockholdersEquity	215257000	USD
CY2020Q1	fnlc	Total Federal Home Loan Bank Advances Treasury Tax Notes And Repurchase Agreements TotalFederalHomeLoanBankAdvancesTreasuryTaxNotesAndRepurchaseAgreements	248040000	USD
CY2020Q2	fnlc	Total Federal Home Loan Bank Advances Treasury Tax Notes And Repurchase Agreements TotalFederalHomeLoanBankAdvancesTreasuryTaxNotesAndRepurchaseAgreements	278805000	USD
CY2020Q3	fnlc	Total Federal Home Loan Bank Advances Treasury Tax Notes And Repurchase Agreements TotalFederalHomeLoanBankAdvancesTreasuryTaxNotesAndRepurchaseAgreements	283787000	USD
CY2020Q4	fnlc	Total Federal Home Loan Bank Advances Treasury Tax Notes And Repurchase Agreements TotalFederalHomeLoanBankAdvancesTreasuryTaxNotesAndRepurchaseAgreements	262038000	USD
CY2021Q1	fnlc	Total Federal Home Loan Bank Advances Treasury Tax Notes And Repurchase Agreements TotalFederalHomeLoanBankAdvancesTreasuryTaxNotesAndRepurchaseAgreements	229648000	USD
CY2021Q2	fnlc	Total Federal Home Loan Bank Advances Treasury Tax Notes And Repurchase Agreements TotalFederalHomeLoanBankAdvancesTreasuryTaxNotesAndRepurchaseAgreements	228648000	USD
CY2021Q3	fnlc	Total Federal Home Loan Bank Advances Treasury Tax Notes And Repurchase Agreements TotalFederalHomeLoanBankAdvancesTreasuryTaxNotesAndRepurchaseAgreements	233201000	USD
CY2021Q4	fnlc	Total Federal Home Loan Bank Advances Treasury Tax Notes And Repurchase Agreements TotalFederalHomeLoanBankAdvancesTreasuryTaxNotesAndRepurchaseAgreements	136342000	USD
CY2020Q1	us-gaap	Other Liabilities OtherLiabilities	28487000	USD
CY2020Q2	us-gaap	Other Liabilities OtherLiabilities	31614000	USD
CY2020Q3	us-gaap	Other Liabilities OtherLiabilities	30340000	USD
CY2020Q4	us-gaap	Other Liabilities OtherLiabilities	30861000	USD
CY2021Q1	us-gaap	Other Liabilities OtherLiabilities	25479000	USD
CY2021Q2	us-gaap	Other Liabilities OtherLiabilities	26319000	USD
CY2021Q3	us-gaap	Other Liabilities OtherLiabilities	24440000	USD
CY2021Q4	us-gaap	Other Liabilities OtherLiabilities	21803000	USD
CY2021Q1	us-gaap	Stockholders Equity StockholdersEquity	228184000	USD
CY2021Q2	us-gaap	Stockholders Equity StockholdersEquity	234155000	USD
CY2021Q3	us-gaap	Stockholders Equity StockholdersEquity	238737000	USD
CY2020Q2	us-gaap	Stockholders Equity StockholdersEquity	216584000	USD
CY2020Q3	us-gaap	Stockholders Equity StockholdersEquity	219440000	USD
CY2020Q4	us-gaap	Stockholders Equity StockholdersEquity	223726000	USD
CY2021Q4	us-gaap	Stockholders Equity StockholdersEquity	245657000	USD
CY2020Q1	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	2136396000	USD
CY2020Q2	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	2267124000	USD
CY2020Q3	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	2296626000	USD
CY2020Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	2361236000	USD
CY2021Q1	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	2436868000	USD
CY2021Q2	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	2450443000	USD
CY2021Q3	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	2529591000	USD
CY2021Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	2527099000	USD
CY2020Q1	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	20694000	USD
CY2020Q2	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	18786000	USD
CY2021Q3	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	19588000	USD
CY2020Q3	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	18506000	USD
CY2020Q4	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	19133000	USD
CY2021Q1	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	18953000	USD
CY2021Q2	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	18541000	USD
CY2021Q4	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	19999000	USD
CY2020Q1	us-gaap	Interest Expense InterestExpense	5776000	USD
CY2020Q2	us-gaap	Interest Expense InterestExpense	4295000	USD
CY2020Q3	us-gaap	Interest Expense InterestExpense	3761000	USD
CY2020Q4	us-gaap	Interest Expense InterestExpense	3454000	USD
CY2021Q1	us-gaap	Interest Expense InterestExpense	3080000	USD
CY2021Q2	us-gaap	Interest Expense InterestExpense	2818000	USD
CY2021Q3	us-gaap	Interest Expense InterestExpense	2577000	USD
CY2021Q4	us-gaap	Interest Expense InterestExpense	2303000	USD
CY2020Q1	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	14918000	USD
CY2020Q2	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	14491000	USD
CY2021Q1	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	15348000	USD
CY2020Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	14745000	USD
CY2020Q4	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	15679000	USD
CY2021Q1	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	15873000	USD
CY2021Q2	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	15723000	USD
CY2021Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	17011000	USD
CY2021Q4	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	17696000	USD
CY2020Q1	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	400000	USD
CY2020Q2	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	2350000	USD
CY2020Q3	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	1800000	USD
CY2020Q4	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	1500000	USD
CY2021Q1	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	525000	USD
CY2021Q2	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	525000	USD
CY2021Q3	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	525000	USD
CY2021Q4	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	-1950000	USD
CY2020Q1	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	14518000	USD
CY2020Q2	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	12141000	USD
CY2020Q3	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	12945000	USD
CY2020Q4	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	14179000	USD
CY2021Q2	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	15198000	USD
CY2021Q3	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	16486000	USD
CY2021Q4	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	19646000	USD
CY2020Q1	us-gaap	Noninterest Income NoninterestIncome	4221000	USD
CY2020Q2	us-gaap	Noninterest Income NoninterestIncome	4601000	USD
CY2020Q3	us-gaap	Noninterest Income NoninterestIncome	4805000	USD
CY2020Q4	us-gaap	Noninterest Income NoninterestIncome	4492000	USD
CY2021Q1	us-gaap	Noninterest Income NoninterestIncome	5298000	USD
CY2021Q2	us-gaap	Noninterest Income NoninterestIncome	4911000	USD
CY2021Q3	us-gaap	Noninterest Income NoninterestIncome	4375000	USD
CY2021Q4	us-gaap	Noninterest Income NoninterestIncome	4799000	USD
CY2020Q1	us-gaap	Noninterest Expense NoninterestExpense	11043000	USD
CY2020Q2	us-gaap	Noninterest Expense NoninterestExpense	8917000	USD
CY2020Q3	us-gaap	Noninterest Expense NoninterestExpense	9276000	USD
CY2020Q4	us-gaap	Noninterest Expense NoninterestExpense	10416000	USD
CY2021Q1	us-gaap	Noninterest Expense NoninterestExpense	9874000	USD
CY2021Q2	us-gaap	Noninterest Expense NoninterestExpense	9496000	USD
CY2021Q3	us-gaap	Noninterest Expense NoninterestExpense	9932000	USD
CY2021Q4	us-gaap	Noninterest Expense NoninterestExpense	12846000	USD
CY2020Q1	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	7696000	USD
CY2020Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	7825000	USD
CY2020Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	8474000	USD
CY2020Q4	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	8255000	USD
CY2021Q1	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	10772000	USD
CY2021Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	10613000	USD
CY2021Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	10929000	USD
CY2021Q4	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	11599000	USD
CY2020Q1	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	1201000	USD
CY2020Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	1256000	USD
CY2020Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	1379000	USD
CY2020Q4	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	1285000	USD
CY2021Q1	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	1850000	USD
CY2021Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	1826000	USD
CY2021Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	1915000	USD
CY2021Q4	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	2053000	USD
CY2020Q1	us-gaap	Net Income Loss NetIncomeLoss	6495000	USD
CY2020Q2	us-gaap	Net Income Loss NetIncomeLoss	6569000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	7095000	USD
CY2020Q4	us-gaap	Net Income Loss NetIncomeLoss	6970000	USD
CY2021Q1	us-gaap	Net Income Loss NetIncomeLoss	8922000	USD
CY2021Q2	us-gaap	Net Income Loss NetIncomeLoss	8787000	USD
CY2021Q3	us-gaap	Net Income Loss NetIncomeLoss	9014000	USD
CY2021Q4	us-gaap	Net Income Loss NetIncomeLoss	9546000	USD
CY2020Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.60
CY2020Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.61
CY2020Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.65
CY2020Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.64
CY2021Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.82
CY2021Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.81
CY2021Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.83
CY2021Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.87
CY2020Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.60
CY2020Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.60
CY2020Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.65
CY2020Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.63
CY2021Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.81
CY2021Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.80
CY2021Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.82
CY2021Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.87
CY2020Q1	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	4233000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-790000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-1580000	USD
CY2020Q4	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-511000	USD
CY2021Q1	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-4790000	USD
CY2021Q2	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	971000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-1817000	USD
CY2021Q4	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-1091000	USD
CY2020Q1	fnlc	Availableforsale Securities Transferredto Heldtomaturity Securities Unrealized Gain Loss AvailableforsaleSecuritiesTransferredtoHeldtomaturitySecuritiesUnrealizedGainLoss	8000	USD
CY2020Q2	fnlc	Availableforsale Securities Transferredto Heldtomaturity Securities Unrealized Gain Loss AvailableforsaleSecuritiesTransferredtoHeldtomaturitySecuritiesUnrealizedGainLoss	28000	USD
CY2020Q3	fnlc	Availableforsale Securities Transferredto Heldtomaturity Securities Unrealized Gain Loss AvailableforsaleSecuritiesTransferredtoHeldtomaturitySecuritiesUnrealizedGainLoss	7000	USD
CY2020Q4	fnlc	Availableforsale Securities Transferredto Heldtomaturity Securities Unrealized Gain Loss AvailableforsaleSecuritiesTransferredtoHeldtomaturitySecuritiesUnrealizedGainLoss	6000	USD
CY2021Q1	fnlc	Availableforsale Securities Transferredto Heldtomaturity Securities Unrealized Gain Loss AvailableforsaleSecuritiesTransferredtoHeldtomaturitySecuritiesUnrealizedGainLoss	9000	USD
CY2021Q2	fnlc	Availableforsale Securities Transferredto Heldtomaturity Securities Unrealized Gain Loss AvailableforsaleSecuritiesTransferredtoHeldtomaturitySecuritiesUnrealizedGainLoss	11000	USD
CY2021Q3	fnlc	Availableforsale Securities Transferredto Heldtomaturity Securities Unrealized Gain Loss AvailableforsaleSecuritiesTransferredtoHeldtomaturitySecuritiesUnrealizedGainLoss	14000	USD
CY2021Q4	fnlc	Availableforsale Securities Transferredto Heldtomaturity Securities Unrealized Gain Loss AvailableforsaleSecuritiesTransferredtoHeldtomaturitySecuritiesUnrealizedGainLoss	12000	USD
CY2020Q1	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	-4870000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	-1414000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	387000	USD
CY2020Q4	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	868000	USD
CY2021Q1	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	3469000	USD
CY2021Q2	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	-620000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	546000	USD
CY2021Q4	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	1537000	USD
CY2020Q1	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
CY2020Q2	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
CY2020Q3	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
CY2020Q4	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	-4000	USD
CY2021Q1	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
CY2021Q2	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
CY2021Q3	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
CY2021Q4	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
CY2020Q1	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-629000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-2176000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-1186000	USD
CY2020Q4	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	367000	USD
CY2021Q1	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-1312000	USD
CY2021Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	362000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-1257000	USD
CY2021Q4	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	535000	USD
CY2020Q1	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	5866000	USD
CY2020Q2	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	4393000	USD
CY2020Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	5909000	USD
CY2020Q4	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	7337000	USD
CY2021Q1	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	7610000	USD
CY2021Q2	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	9149000	USD
CY2021Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	7757000	USD
CY2021Q4	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	10081000	USD
CY2021	dei	Auditor Name AuditorName	Berry Dunn McNeil & Parker, LLC
CY2021	dei	Auditor Firm AuditorFirmId	136
CY2021	dei	Auditor Location AuditorLocation	Portland, Maine

Files In Submission

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

2021 Q3 Form 10-K Financial Statement

#000076520722000010 Filed on March 11, 2022

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

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

2021 Q3 Form 10-K Financial Statement

#000076520722000010 Filed on March 11, 2022

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

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