Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (i)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(2)(iii)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_VestingAxis=fnlc_PeriodOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PlanNameAxis=fnlc_Plan2010Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_RestrictedStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VestingAxis=fnlc_FiveYearsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VestingAxis=fnlc_FourYearsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VestingAxis=fnlc_ThreeYearsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VestingAxis=fnlc_TwoYearsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Stock Options and Stock-Based Compensation - Shares of Restricted Stock Granted under 2010 Plan (Details) - shares	6 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares	86,336
Period One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting Term (In Years)	2 years
Plan 2010 \| Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares	66,644
Remaining Term (In Years)	2 years 3 months 18 days
Plan 2010 \| Five Years \| Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting Term (In Years)	5 years	5 years	5 years	5 years	5 years
Shares	11,496	10,422	14,776	7,996	5,500
Remaining Term (In Years)	4 years 7 months 6 days	3 years 7 months 6 days	2 years 7 months 6 days	1 year 8 months 12 days	7 months 6 days
Plan 2010 \| Four Years \| Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting Term (In Years)				4 years
Shares				2,704
Remaining Term (In Years)				8 months 12 days
Plan 2010 \| Three Years \| Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting Term (In Years)			3 years
Shares			3,808
Remaining Term (In Years)			7 months 6 days
Plan 2010 \| Two Years \| Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting Term (In Years)		2 years
Shares		7,786
Remaining Term (In Years)		7 months 6 days
Plan 2010 \| Period One \| Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting Term (In Years)	1 year
Shares	2,156
Remaining Term (In Years)	7 months 6 days