XML 130 R116.htm IDEA: XBRL DOCUMENT
v3.25.0.1

Fair Value Disclosures - Carrying Amounts and Estimated Fair Values (Details) - USD ($) $ in Thousands | Dec. 31, 2024 | Sep. 30, 2024 | Jun. 30, 2024 | Mar. 31, 2024 | Dec. 31, 2023 | Sep. 30, 2023 | Jun. 30, 2023 | Mar. 31, 2023
--- | --- | --- | --- | --- | --- | --- | --- | ---
Financial assets |  |  |  |  |  |  |  |
Securities to be held to maturity (net of allowance for credit losses) | $ 314,993 |  |  |  | $ 338,570 |  |  |
Mortgage servicing rights | 3,054 |  |  |  | 3,583 |  |  |
Financial liabilities |  |  |  |  |  |  |  |
Certificates of deposit | 1,114,811 |  |  |  | 1,070,247 |  |  |
Total deposits | 2,725,251 | $ 2,702,718 | $ 2,578,080 | $ 2,548,988 | 2,599,662 | $ 2,599,937 | $ 2,499,862 | $ 2,466,701
Carrying value |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Securities to be held to maturity (net of allowance for credit losses) | 369,704 |  |  |  | 385,235 |  |  |
Loans held for sale | 0 |  |  |  |  |  |  |
Total loans | 2,316,069 |  |  |  | 2,105,424 |  |  |
Mortgage servicing rights | 1,894 |  |  |  | 2,177 |  |  |
Financial liabilities |  |  |  |  |  |  |  |
Certificates of deposit | 385,897 |  |  |  | 293,466 |  |  |
National certificates of deposit | 728,914 |  |  |  | 776,781 |  |  |
Total deposits | 1,114,811 |  |  |  | 1,070,247 |  |  |
Repurchase agreements | 51,278 |  |  |  | 49,576 |  |  |
Other borrowed funds | 95,000 |  |  |  | 20,076 |  |  |
Total borrowed funds | 146,278 |  |  |  | 69,652 |  |  |
Carrying value | Commercial | Real Estate |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 752,613 |  |  |  | 699,537 |  |  |
Carrying value | Commercial | Construction |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 98,773 |  |  |  | 86,695 |  |  |
Carrying value | Commercial | Other |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 519,560 |  |  |  | 443,944 |  |  |
Carrying value | Municipal |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 61,565 |  |  |  | 51,089 |  |  |
Carrying value | Residential | Construction |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 35,007 |  |  |  | 31,740 |  |  |
Carrying value | Residential | Term |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 705,566 |  |  |  | 669,864 |  |  |
Carrying value | Home Equity |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 122,377 |  |  |  | 103,400 |  |  |
Carrying value | Consumer |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 20,608 |  |  |  | 19,155 |  |  |
Total Fair Value |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Securities to be held to maturity (net of allowance for credit losses) | 314,993 |  |  |  | 338,570 |  |  |
Loans held for sale | 0 |  |  |  |  |  |  |
Total loans | 2,202,820 |  |  |  | 1,964,228 |  |  |
Mortgage servicing rights | 3,054 |  |  |  | 3,583 |  |  |
Financial liabilities |  |  |  |  |  |  |  |
Certificates of deposit | 365,937 |  |  |  | 362,555 |  |  |
National certificates of deposit | 747,681 |  |  |  | 699,919 |  |  |
Total deposits | 1,113,618 |  |  |  | 1,062,474 |  |  |
Repurchase agreements | 51,181 |  |  |  | 49,462 |  |  |
Other borrowed funds | 95,066 |  |  |  | 20,074 |  |  |
Total borrowed funds | 146,247 |  |  |  | 69,536 |  |  |
Total Fair Value | Commercial | Real Estate |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 720,898 |  |  |  | 658,732 |  |  |
Total Fair Value | Commercial | Construction |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 94,611 |  |  |  | 81,638 |  |  |
Total Fair Value | Commercial | Other |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 513,417 |  |  |  | 431,067 |  |  |
Total Fair Value | Municipal |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 57,657 |  |  |  | 46,806 |  |  |
Total Fair Value | Residential | Construction |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 34,631 |  |  |  | 31,131 |  |  |
Total Fair Value | Residential | Term |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 643,402 |  |  |  | 595,033 |  |  |
Total Fair Value | Home Equity |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 119,930 |  |  |  | 102,858 |  |  |
Total Fair Value | Consumer |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 18,274 |  |  |  | 16,963 |  |  |
Total Fair Value | Level 1 |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Securities to be held to maturity (net of allowance for credit losses) | 0 |  |  |  | 0 |  |  |
Loans held for sale | 0 |  |  |  |  |  |  |
Total loans | 0 |  |  |  | 0 |  |  |
Mortgage servicing rights | 0 |  |  |  | 0 |  |  |
Financial liabilities |  |  |  |  |  |  |  |
Certificates of deposit | 0 |  |  |  | 0 |  |  |
National certificates of deposit | 0 |  |  |  | 0 |  |  |
Total deposits | 0 |  |  |  | 0 |  |  |
Repurchase agreements | 0 |  |  |  | 0 |  |  |
Other borrowed funds | 0 |  |  |  | 0 |  |  |
Total borrowed funds | 0 |  |  |  | 0 |  |  |
Total Fair Value | Level 1 | Commercial | Real Estate |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 0 |  |  |  | 0 |  |  |
Total Fair Value | Level 1 | Commercial | Construction |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 0 |  |  |  | 0 |  |  |
Total Fair Value | Level 1 | Commercial | Other |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 0 |  |  |  | 0 |  |  |
Total Fair Value | Level 1 | Municipal |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 0 |  |  |  | 0 |  |  |
Total Fair Value | Level 1 | Residential | Construction |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 0 |  |  |  | 0 |  |  |
Total Fair Value | Level 1 | Residential | Term |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 0 |  |  |  | 0 |  |  |
Total Fair Value | Level 1 | Home Equity |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 0 |  |  |  | 0 |  |  |
Total Fair Value | Level 1 | Consumer |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 0 |  |  |  | 0 |  |  |
Total Fair Value | Level 2 |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Securities to be held to maturity (net of allowance for credit losses) | 314,993 |  |  |  | 338,570 |  |  |
Loans held for sale | 0 |  |  |  |  |  |  |
Total loans | 538 |  |  |  | 285 |  |  |
Mortgage servicing rights | 3,054 |  |  |  | 3,583 |  |  |
Financial liabilities |  |  |  |  |  |  |  |
Certificates of deposit | 365,937 |  |  |  | 362,555 |  |  |
National certificates of deposit | 747,681 |  |  |  | 699,919 |  |  |
Total deposits | 1,113,618 |  |  |  | 1,062,474 |  |  |
Repurchase agreements | 51,181 |  |  |  | 49,462 |  |  |
Other borrowed funds | 95,066 |  |  |  | 20,074 |  |  |
Total borrowed funds | 146,247 |  |  |  | 69,536 |  |  |
Total Fair Value | Level 2 | Commercial | Real Estate |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 0 |  |  |  | 0 |  |  |
Total Fair Value | Level 2 | Commercial | Construction |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 0 |  |  |  | 0 |  |  |
Total Fair Value | Level 2 | Commercial | Other |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 538 |  |  |  | 0 |  |  |
Total Fair Value | Level 2 | Municipal |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 0 |  |  |  | 0 |  |  |
Total Fair Value | Level 2 | Residential | Construction |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 0 |  |  |  | 0 |  |  |
Total Fair Value | Level 2 | Residential | Term |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 0 |  |  |  | 285 |  |  |
Total Fair Value | Level 2 | Home Equity |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 0 |  |  |  | 0 |  |  |
Total Fair Value | Level 2 | Consumer |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 0 |  |  |  | 0 |  |  |
Total Fair Value | Level 3 |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Securities to be held to maturity (net of allowance for credit losses) | 0 |  |  |  | 0 |  |  |
Loans held for sale | 0 |  |  |  |  |  |  |
Total loans | 2,202,282 |  |  |  | 1,963,943 |  |  |
Mortgage servicing rights | 0 |  |  |  | 0 |  |  |
Financial liabilities |  |  |  |  |  |  |  |
Certificates of deposit | 0 |  |  |  | 0 |  |  |
National certificates of deposit | 0 |  |  |  | 0 |  |  |
Total deposits | 0 |  |  |  | 0 |  |  |
Repurchase agreements | 0 |  |  |  | 0 |  |  |
Other borrowed funds | 0 |  |  |  | 0 |  |  |
Total borrowed funds | 0 |  |  |  | 0 |  |  |
Total Fair Value | Level 3 | Commercial | Real Estate |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 720,898 |  |  |  | 658,732 |  |  |
Total Fair Value | Level 3 | Commercial | Construction |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 94,611 |  |  |  | 81,638 |  |  |
Total Fair Value | Level 3 | Commercial | Other |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 512,879 |  |  |  | 431,067 |  |  |
Total Fair Value | Level 3 | Municipal |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 57,657 |  |  |  | 46,806 |  |  |
Total Fair Value | Level 3 | Residential | Construction |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 34,631 |  |  |  | 31,131 |  |  |
Total Fair Value | Level 3 | Residential | Term |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 643,402 |  |  |  | 594,748 |  |  |
Total Fair Value | Level 3 | Home Equity |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | 119,930 |  |  |  | 102,858 |  |  |
Total Fair Value | Level 3 | Consumer |  |  |  |  |  |  |  |
Financial assets |  |  |  |  |  |  |  |
Total loans | $ 18,274 |  |  |  | $ 16,963 |  |  |

X
- Definition The aggregate amount of national time deposits, including certificates of deposits, individual retirement accounts and open accounts. + References No definition available. + Details
Name: | fnlc_NationalCertificatesOfDeposit
Namespace Prefix: | fnlc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount, including accrued interest, to be repaid to counterparty to repurchase agreement when carrying amount or market value if higher, of security or other asset sold under repurchase agreement exceeds 10 percent of total assets. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 860 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 7 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481420/860-30-50-7 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 860 -SubTopic 30 -Name Accounting Standards Codification -Section 45 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481444/860-30-45-2 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08(m)(1)(i)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480678/235-10-S99-1 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08(m)(1)(ii)(A)(ii)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480678/235-10-S99-1 + Details
Name: | us-gaap_AssetsSoldUnderAgreementsToRepurchaseRepurchaseLiability
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of short-term and long-term debt and lease obligation. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(13)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1 + Details
Name: | us-gaap_DebtAndCapitalLeaseObligations
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The aggregate of all deposit liabilities held by the entity, including foreign and domestic, interest and noninterest bearing; may include demand deposits, saving deposits, Negotiable Order of Withdrawal (NOW) and time deposits among others. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(12)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1 + Details
Name: | us-gaap_Deposits
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Fair value of investment in debt security measured at amortized cost (held-to-maturity). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2E -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2E Reference 3: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (aa) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-5 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(1)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5A -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-5A Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(6)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1 + Details
Name: | us-gaap_HeldToMaturitySecuritiesFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 10 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-10 + Details
Name: | us-gaap_LoansReceivableFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount, after valuation allowance, of financing receivable held for sale and not part of disposal group. Excludes loan covered under loss sharing agreement and loan classified as investment in debt security. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481990/310-10-45-2 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 948 -SubTopic 310 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477011/948-310-45-1 + Details
Name: | us-gaap_LoansReceivableHeldForSaleNetNotPartOfDisposalGroup
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The carrying amount as of the balance sheet date for the aggregate of other miscellaneous borrowings owed by the reporting entity. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(13)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1 + Details
Name: | us-gaap_OtherBorrowings
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Fair value of an asset representing net future revenue from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 860 -SubTopic 50 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481229/860-50-50-3 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 860 -SubTopic 50 -Name Accounting Standards Codification -Section 45 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481260/860-50-45-2 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 860 -SubTopic 50 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481260/860-50-45-1 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 860 -SubTopic 50 -Name Accounting Standards Codification -Section 45 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481260/860-50-45-2 + Details
Name: | us-gaap_ServicingAssetAtFairValueAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of time deposit liabilities, including certificates of deposit. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 50 -Paragraph 1 -SubTopic 405 -Topic 942 -Publisher FASB -URI https://asc.fasb.org/1943274/2147478353/942-405-50-1 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(12)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1 + Details
Name: | us-gaap_TimeDeposits
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_FairValueByMeasurementBasisAxis=us-gaap_CarryingReportedAmountFairValueDisclosureMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_RealEstateLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_ConstructionLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=fnlc_OtherLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=fnlc_MunicipalPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ResidentialPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=fnlc_TermLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=fnlc_HomeEquityLineOfCreditPortfolioMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByMeasurementBasisAxis=us-gaap_EstimateOfFairValueFairValueDisclosureMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |