Represents the portion of the balance sheet assertion valued at fair value whether such amount is presented as a separate caption or as a parenthetical disclosure. Element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. May be used in both the balance sheet and disclosure in the same submission. This item represents the amount shown on an entity's books for accrued interest receivable.

No definition available.

Fair Value Disclosures, Part 2 (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013
Financial assets
Securities available for sale	$ 185,261us-gaap_AvailableForSaleSecurities				$ 305,824us-gaap_AvailableForSaleSecurities
Securities to be held to maturity, fair value	279,704				158,336
Restricted equity securities, at cost	13,912fnlc_RestrictedEquitySecuritiesAtCost				13,912fnlc_RestrictedEquitySecuritiesAtCost
Residential [Abstract]
Total loans	907,220				864,853
Mortgage servicing rights	2,088us-gaap_ServicingAssetAtFairValueAmount				1,948us-gaap_ServicingAssetAtFairValueAmount
Financial liabilities
Demand deposits	113,133us-gaap_DemandDepositAccounts				106,125us-gaap_DemandDepositAccounts
NOW deposits	199,977				151,322
Money market deposits	98,607us-gaap_DepositsMoneyMarketDeposits				86,730us-gaap_DepositsMoneyMarketDeposits
Savings deposits	165,601us-gaap_DepositsSavingsDeposits				149,103us-gaap_DepositsSavingsDeposits
Certificates of deposit	447,501us-gaap_TimeDeposits				531,119us-gaap_TimeDeposits
Total deposits	1,024,819us-gaap_Deposits	1,055,322us-gaap_Deposits	1,033,436us-gaap_Deposits	1,045,970us-gaap_Deposits	1,024,399us-gaap_Deposits	1,037,466us-gaap_Deposits	1,027,682us-gaap_Deposits	975,861us-gaap_Deposits
Carrying Amount
Financial assets
Cash and cash equivalents	13,057				16,570
Interest bearing deposits in other banks	3,559				2,562
Securities available for sale	185,261				305,824
Securities to be held to maturity, fair value	275,919				169,277
Restricted equity securities, at cost	13,912				13,912
Loans held for sale					83
Commercial [Abstract]
Municipal	20,406				19,099
Residential [Abstract]
Home equity line of credit	102,258				90,759
Consumer	19,007				14,396
Total loans	907,220				864,853
Mortgage servicing rights	1,086				1,158
Accrued interest receivable	4,748				5,038
Financial liabilities
Demand deposits	113,133				106,125
NOW deposits	199,977				151,322
Money market deposits	98,607				86,730
Savings deposits	165,601				149,103
Certificates of deposit	205,072				226,658
National certificates of deposit	242,429				304,461
Total deposits	1,024,819				1,024,399
Repurchase agreements	74,725				94,477
Federal Home Loan Bank advances	205,191				184,648
Total borrowed funds	279,916				279,125
Accrued interest payable	521				599
Estimate of Fair Value
Financial assets
Cash and cash equivalents	13,057				16,570
Interest bearing deposits in other banks	3,559				2,562
Securities available for sale	185,261				305,824
Securities to be held to maturity, fair value	279,704				158,336
Restricted equity securities, at cost	13,912				13,912
Loans held for sale					83
Commercial [Abstract]
Municipal	20,833				19,358
Residential [Abstract]
Home equity line of credit	101,733				90,542
Consumer	19,207				14,438
Total loans	912,055				870,539
Mortgage servicing rights	2,088				1,948
Accrued interest receivable	4,748				5,038
Financial liabilities
Demand deposits	109,973				96,175
NOW deposits	186,490				129,815
Money market deposits	83,837				67,968
Savings deposits	146,936				122,891
Certificates of deposit	205,360				228,767
National certificates of deposit	242,824				306,346
Total deposits	975,420				951,962
Repurchase agreements	70,783				94,477
Federal Home Loan Bank advances	208,259				189,644
Total borrowed funds	279,042				284,121
Accrued interest payable	521				599
Commercial Real Estate Receivable \| Carrying Amount
Commercial [Abstract]
Loans	238,104				240,555
Commercial Real Estate Receivable \| Estimate of Fair Value
Commercial [Abstract]
Loans	236,368				239,973
Commercial Construction \| Carrying Amount
Commercial [Abstract]
Loans	29,951				19,709
Commercial Construction \| Estimate of Fair Value
Commercial [Abstract]
Loans	29,733				19,661
Commercial Other Receivable \| Carrying Amount
Commercial [Abstract]
Loans	102,738				92,625
Commercial Other Receivable \| Estimate of Fair Value
Commercial [Abstract]
Loans	102,858				92,855
Residential, Term, Financing Receivable \| Carrying Amount
Residential [Abstract]
Loans	382,620				375,932
Residential, Term, Financing Receivable \| Estimate of Fair Value
Residential [Abstract]
Loans	389,200				381,918
Residential, Construction, Financing Receivables \| Carrying Amount
Residential [Abstract]
Loans	12,136				11,778
Residential, Construction, Financing Receivables \| Estimate of Fair Value
Residential [Abstract]
Loans	12,123				11,794
Fair Value, Inputs, Level 1
Financial assets
Cash and cash equivalents	13,057				16,570
Interest bearing deposits in other banks	3,559				2,562
Securities available for sale	0				0
Securities to be held to maturity, fair value	0				0
Restricted equity securities, at cost	0				0
Loans held for sale					0
Commercial [Abstract]
Municipal	0				0
Residential [Abstract]
Home equity line of credit	0				0
Consumer	0				0
Total loans	0				0
Mortgage servicing rights	0				0
Accrued interest receivable	0				0
Financial liabilities
Demand deposits	0				0
NOW deposits	0				0
Money market deposits	0				0
Savings deposits	0				0
Certificates of deposit	0				0
National certificates of deposit	0				0
Total deposits	0				0
Repurchase agreements	0				0
Federal Home Loan Bank advances	0				0
Total borrowed funds	0				0
Accrued interest payable	0				0
Fair Value, Inputs, Level 1 \| Commercial Real Estate Receivable
Commercial [Abstract]
Loans	0				0
Fair Value, Inputs, Level 1 \| Commercial Construction
Commercial [Abstract]
Loans	0				0
Fair Value, Inputs, Level 1 \| Commercial Other Receivable
Commercial [Abstract]
Loans	0				0
Fair Value, Inputs, Level 1 \| Residential, Term, Financing Receivable
Residential [Abstract]
Loans	0				0
Fair Value, Inputs, Level 1 \| Residential, Construction, Financing Receivables
Residential [Abstract]
Loans	0				0
Fair Value, Inputs, Level 2
Financial assets
Cash and cash equivalents	0				0
Interest bearing deposits in other banks	0				0
Securities available for sale	185,261				305,824
Securities to be held to maturity, fair value	279,704				158,336
Restricted equity securities, at cost	13,912				13,912
Loans held for sale					83
Commercial [Abstract]
Municipal	0				0
Residential [Abstract]
Home equity line of credit	488				0
Consumer	0				0
Total loans	1,909				1,116
Mortgage servicing rights	2,088				1,948
Accrued interest receivable	4,748				5,038
Financial liabilities
Demand deposits	109,973				96,175
NOW deposits	186,490				129,815
Money market deposits	83,837				67,968
Savings deposits	146,936				122,891
Certificates of deposit	205,360				228,767
National certificates of deposit	242,824				306,346
Total deposits	975,420				951,962
Repurchase agreements	70,783				94,477
Federal Home Loan Bank advances	208,259				189,644
Total borrowed funds	279,042				284,121
Accrued interest payable	521				599
Fair Value, Inputs, Level 2 \| Commercial Real Estate Receivable
Commercial [Abstract]
Loans	431				109
Fair Value, Inputs, Level 2 \| Commercial Construction
Commercial [Abstract]
Loans	0				0
Fair Value, Inputs, Level 2 \| Commercial Other Receivable
Commercial [Abstract]
Loans	0				229
Fair Value, Inputs, Level 2 \| Residential, Term, Financing Receivable
Residential [Abstract]
Loans	990				778
Fair Value, Inputs, Level 2 \| Residential, Construction, Financing Receivables
Residential [Abstract]
Loans	0				0
Fair Value, Inputs, Level 3
Financial assets
Cash and cash equivalents	0				0
Interest bearing deposits in other banks	0				0
Securities available for sale	0				0
Securities to be held to maturity, fair value	0				0
Restricted equity securities, at cost	0				0
Loans held for sale					0
Commercial [Abstract]
Municipal	20,833				19,358
Residential [Abstract]
Home equity line of credit	101,245				90,542
Consumer	19,207				14,438
Total loans	910,146				869,423
Mortgage servicing rights	0				0
Accrued interest receivable	0				0
Financial liabilities
Demand deposits	0				0
NOW deposits	0				0
Money market deposits	0				0
Savings deposits	0				0
Certificates of deposit	0				0
National certificates of deposit	0				0
Total deposits	0				0
Repurchase agreements	0				0
Federal Home Loan Bank advances	0				0
Total borrowed funds	0				0
Accrued interest payable	0				0
Fair Value, Inputs, Level 3 \| Commercial Real Estate Receivable
Commercial [Abstract]
Loans	235,937				239,864
Fair Value, Inputs, Level 3 \| Commercial Construction
Commercial [Abstract]
Loans	29,733				19,661
Fair Value, Inputs, Level 3 \| Commercial Other Receivable
Commercial [Abstract]
Loans	102,858				92,626
Fair Value, Inputs, Level 3 \| Residential, Term, Financing Receivable
Residential [Abstract]
Loans	388,210				381,140
Fair Value, Inputs, Level 3 \| Residential, Construction, Financing Receivables
Residential [Abstract]
Loans	$ 12,123				$ 11,794