XML 16 R5.htm IDEA: XBRL DOCUMENT
v3.21.1

Consolidated Statements of Income and Comprehensive Income (Unaudited) (Parenthetical) - USD ($) $ in Thousands | 3 Months Ended
--- | ---
Mar. 31, 2021 | Mar. 31, 2020
Income Statement [Abstract] |  |
Interest and fees on loans (tax-exempt income) | $ 290 | $ 310
Interest and dividends on investments (tax-exempt income) | $ 1,956 | $ 1,841

X
- Definition Interest Income and Fees on Loans Tax Exempt + References No definition available. + Details
Name: | fnlc_InterestIncomeandFeesonLoansTaxExempt
Namespace Prefix: | fnlc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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

X
- Definition Amount of operating interest income, including amortization and accretion of premiums and discounts, on securities exempt from state, federal and other income tax. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 220 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04.2) -URI http://asc.fasb.org/extlink&oid=120399700&loc=SL114874048-224260 + Details
Name: | us-gaap_InterestIncomeSecuritiesTaxExempt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration