| **Condensed Financial Information of Parent**                                    | 12 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
|----------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
||
| **Condensed Financial Information of Parent Company Only Disclosure [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
| Condensed Financial Information of Parent                                        | Note 23. Condensed Financial Information of ParentCondensed financial information for The First Bancorp, Inc. exclusive of its subsidiary is as follows:Balance SheetsAs of December 31, 2012  2011 Assets    Cash and cash equivalents $2,685,000  $894,000 Dividends receivable  1,900,000   1,900,000 Investments  429,000   327,000 Investment in subsidiary  125,580,000   122,009,000 Premises and equipment  43,000   26,000 Goodwill  27,559,000   27,559,000 Other assets  72,000   57,000         Total assets $158,268,000  $152,772,000 Liabilities and shareholders' equity        Dividends payable $1,923,000  $1,912,000 Other liabilities  22,000   2,000      Total liabilities  1,945,000   1,914,000 Shareholders' equity        Preferred stock  12,402,000   12,303,000 Common stock  98,000   98,000 Additional paid-in capital  46,314,000   45,829,000 Retained earnings  97,509,000   92,694,000 Accumulated other comprehensive loss        Net unrealized loss on available for sale securities,net of tax benefit of $33,000 in 2011  -   (66,000)  Total accumulated other comprehensive loss  -   (66,000)    Total shareholders' equity  156,323,000   150,858,000        Total liabilities and shareholders' equity $158,268,000  $152,772,000 Statements of IncomeFor the years ended December 31, 2012  2011  2010 Interest and dividends on investments $10,000  $10,000  $10,000 Net securities gains  -   153,000   - Total income  10,000   163,000   10,000 Occupancy expense  8,000   4,000   1,000 Other operating expense  218,000   137,000   150,000 Total expense  226,000   141,000   151,000 Income (loss) before income taxes  (216,000)  22,000   (141,000)Applicable income taxes  (76,000)  15,000   (38,000)Income (loss) before Bank earnings  (140,000)  7,000   (103,000)Equity in earnings of Bank            Remitted  9,694,000   8,710,000   8,850,000 Unremitted  3,134,000   3,647,000   3,369,000      Net income $12,688,000  $12,364,000  $12,116,000 Statements of Cash FlowsFor the years ended December 31, 2012  2011  2010 Cash flows from operating activities:      Net income $12,688,000  $12,364,000  $12,116,000 Adjustments to reconcile net income to net cash provided by operating activities:   Depreciation  8,000   13,000   -   Equity compensation expense  85,000   22,000   37,000   Gain on sale of investment  -   (153,000)  -   Increase in other assets  (15,000)  (42,000)  (1,000)  Increase (decrease) in other liabilities  (5,000)  44,000   5,000   Unremitted earnings of Bank  (3,134,000)  (3,647,000)  (3,369,000)   Net cash provided by operating activities  9,627,000   8,601,000   8,788,000 Cash flows from investing activities:              Proceeds from sales/maturities of investments  -   12,773,000   -   Purchases of investments  -   (273,000)  -   Capital expenditures  (25,000)  (29,000)  (10,000)   Net cash provided by (used in) investing activities  (25,000)  12,471,000   (10,000)Cash flows from financing activities:              Payment to repurchase preferred stock  -   (12,500,000)  -   Proceeds from sale of common stock  499,000   431,000   416,000   Dividends paid  (8,310,000)  (8,751,000)  (8,865,000)   Net cash used in financing activities  (7,811,000)  (20,820,000)  (8,449,000)Net increase in cash and cash equivalents  1,791,000   252,000   329,000 Cash and cash equivalents at beginning of year  894,000   642,000   313,000 Cash and cash equivalents at end of year $2,685,000  $894,000  $642,000  |

| X                                                                                                                                                                                                      |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_CondensedFinancialInformationOfParentCompanyOnlyDisclosureAbstract**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The entire disclosure for condensed financial information, including the financial position, cash flows, and the results of operations of the registrant (parent company) as of the same dates or for the same periods for which audited consolidated financial statements are being presented. Alternatively, the details of this disclosure can be reported by the specific parent company taxonomy elements, indicating the appropriate date and period contexts in an instance document.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Article 9 -Section 06Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Article 7 -Section 05 -Paragraph cReference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph c -Article 5Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 3 -Subparagraph (SX 210.12-04) -URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e24072-122690Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 24 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.  This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Article 12Reference 7: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=6921628&loc=d3e5283-111683
+ Details**Name:**us-gaap_CondensedFinancialInformationOfParentCompanyOnlyDisclosureTextBlock**Namespace Prefix:**us-gaap_**Data Type:**nonnum:textBlockItemType**Balance Type:**na**Period Type:**duration |