| **Certificates of Deposit (Tables)**   | 3 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
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| **Certificates of Deposit [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
| Certificates of deposit                | The following table represents the breakdown of Certificates of Deposit at March 31, 2012 and 2011, and at December 31, 2011:   March 31, 2012  December 31, 2011  March 31, 2011 Certificates of deposit < $100,000 $248,582,000  $216,836,000  $308,127,000 Certificates $100,000 to $250,000  349,643,000   309,841,000   337,018,000 Certificates $250,000 and over  32,548,000   22,499,000   35,440,000    $630,773,000  $549,176,000  $680,585,000  |

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| - Definition
The tabular disclosure of the breakdown of the balance of time deposits.
+ References
No definition available.
+ Details**Name:**fnlc_TimeDepositsTableTextBlock**Namespace Prefix:**fnlc_**Data Type:**nonnum:textBlockItemType**Balance Type:**na**Period Type:**duration |
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| - Details**Name:**us-gaap_BankingAndThriftAbstract**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |