| **Allowance for Loan Losses (Tables)**                                      | 3 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          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| **Allowance for Loan and Lease Losses, Provision for Loss, Net [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           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| Allowance for loan losses by class of financing receivable and allowance    | December 31, 2011, and March 31, 2011, by class of financing receivable and allowance element, is presented in the following tables: As of March 31, 2012 Specific Reserves on Loans Evaluated Individually for Impairment  General Reserves Based on Historical Loss Experience  Reserves for Qualitative Factors  UnallocatedReserves  Total Reserves Commercial                  Real estate $944,000  $2,648,000  $2,270,000  $-  $5,862,000    Construction  117,000   316,000   271,000   -   704,000    Other  480,000   886,000   759,000   -   2,125,000 Municipal  -   -   19,000   -   19,000 Residential                       Term  592,000   185,000   459,000   -   1,236,000    Construction  49,000   2,000   8,000   -   59,000 Home equity line of credit  156,000   176,000   350,000   -   682,000 Consumer  10,000   319,000   239,000   -   568,000 Unallocated  -   -   -   1,699,000   1,699,000    $2,348,000  $4,532,000  $4,375,000  $1,699,000  $12,954,000  As of December 31, 2011 Specific Reserves on Loans Evaluated Individually for Impairment  General Reserves Based on Historical Loss Experience  Reserves for Qualitative Factors  Unallocated Reserves  Total Reserves Commercial                  Real estate $808,000  $2,578,000  $2,273,000  $-  $5,659,000    Construction  33,000   332,000   293,000   -   658,000    Other  402,000   883,000   778,000   -   2,063,000 Municipal  -   -   19,000   -   19,000 Residential                       Term  478,000   222,000   459,000   -   1,159,000    Construction  235,000   6,000   14,000   -   255,000 Home equity line of credit  91,000   149,000   355,000   -   595,000 Consumer  11,000   331,000   242,000   -   584,000 Unallocated  -   -   -   2,008,000   2,008,000    $2,058,000  $4,501,000  $4,433,000  $2,008,000  $13,000,000  As of March 31, 2011 Specific Reserves Evaluated Individually for Impairment  General Reserves Based on Historical Loss Experience  Reserves for Qualitative Factors  UnallocatedReserves  Total Reserves Commercial                  Real estate $593,000  $2,536,000  $3,181,000  $-  $6,310,000    Construction  -   284,000   355,000   -   639,000    Other  326,000   980,000   1,229,000   -   2,535,000 Municipal  -   -   19,000   -   19,000 Residential                       Term  381,000   457,000   567,000   -   1,405,000    Construction  106,000   18,000   22,000   -   146,000 Home equity line of credit  139,000   67,000   472,000   -   678,000 Consumer  76,000   380,000   257,000   -   713,000 Unallocated  -   -   -   1,555,000   1,555,000    $1,621,000  $4,722,000  $6,102,000  $1,555,000  $14,000,000                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
| Summary of Risk Ratings for Loans                                           | The following table summarizes the risk ratings for the Company's commercial real estate, commercial construction, commercial other, and municipal loans as of March 31, 2012:   CommercialReal Estate  CommercialConstruction  CommercialOther  MunicipalLoans  All Risk-Rated Loans 1 Strong $23,000  $-  $486,000  $1,911,000  $2,420,000 2 Above Average  19,788,000   -   4,418,000   7,602,000   31,808,000 3 Satisfactory  32,903,000   1,396,000   12,183,000   3,819,000   50,301,000 4 Average  105,446,000   19,130,000   31,412,000   2,629,000   158,617,000 5 Watch  42,680,000   3,530,000   19,473,000   -   65,683,000 6 OAEM  18,302,000   538,000   4,644,000   -   23,484,000 7 Substandard  34,887,000   6,234,000   12,158,000   -   53,279,000 8 Doubtful  679,000   -   693,000   -   1,372,000 Total $254,708,000  $30,828,000  $85,467,000  $15,961,000  $386,964,000 The following table summarizes the risk ratings for the Company's commercial real estate, commercial construction, commercial other, and municipal loans as of December 31, 2011:   CommercialReal Estate  CommercialConstruction  CommercialOther  MunicipalLoans  All Risk-Rated Loans 1 Strong $23,000  $-  $465,000  $2,158,000  $2,646,000 2 Above Average  21,334,000   -   4,229,000   7,509,000   33,072,000 3 Satisfactory  33,119,000   1,365,000   10,981,000   3,861,000   49,326,000 4 Average  106,171,000   17,125,000   31,600,000   2,693,000   157,589,000 5 Watch  44,215,000   3,287,000   17,893,000   -   65,395,000 6 OAEM  18,309,000   2,320,000   5,303,000   -   25,932,000 7 Substandard  31,575,000   7,323,000   16,362,000   -   55,260,000 8 Doubtful  678,000   1,154,000   149,000   -   1,981,000  Total $255,424,000  $32,574,000  $86,982,000  $16,221,000  $391,201,000 The following table summarizes the risk ratings for the Company's commercial real estate, commercial construction, commercial other, and municipal loans as of March 31, 2011:   CommercialReal Estate  CommercialConstruction  CommercialOther  MunicipalLoans  All Risk-Rated Loans 1 Strong $30,000  $-  $462,000  $2,448,000  $2,940,000 2 Above Average  21,270,000   10,000   4,399,000   11,417,000   37,096,000 3 Satisfactory  45,331,000   10,000   17,258,000   4,023,000   66,622,000 4 Average  120,462,000   14,650,000   40,071,000   2,946,000   178,129,000 5 Watch  26,660,000   5,896,000   12,425,000   -   44,981,000 6 OAEM  18,797,000   3,948,000   6,700,000   -   29,445,000 7 Substandard  31,250,000   4,802,000   20,447,000   -   56,499,000 8 Doubtful  -   -   -   -   -  Total $263,800,000  $29,316,000  $101,762,000  $20,834,000  $415,712,000                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            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| Allowance for Loan Losses Transactions                                      | Allowance for loan losses transactions for the three months ended March 31, 2012 and 2011 and for the year ended December 31, 2011 were as follows: For the three months ended Commercial  Municipal  Residential  Home Equity  Consumer  Unallocated  Total March 31, 2012 Real Estate  Construction  Other     Term  Construction  Line of Credit          Allowance for loan losses:                              Beginning balance $5,659,000  $658,000  $2,063,000  $19,000  $1,159,000  $255,000  $595,000  $584,000  $2,008,000  $13,000,000 Charge offs  -   -   2,002,000   -   239,000   -   49,000   180,000   -   2,470,000 Recoveries  -   246,000   2,000   -   1,000   -   -   75,000   -   324,000 Provision  203,000   (200,000)  2,062,000   -   315,000   (196,000)  136,000   89,000   (309,000)  2,100,000 Ending balance $5,862,000  $704,000  $2,125,000  $19,000  $1,236,000  $59,000  $682,000  $568,000  $1,699,000  $12,954,000 Ending balance specifically evaluated for impairment $944,000  $117,000  $480,000  $-  $592,000  $49,000  $156,000  $10,000  $-  $2,348,000 Ending balance collectively evaluated for impairment $4,918,000  $587,000  $1,645,000  $19,000  $644,000  $10,000  $526,000  $558,000  $1,699,000  $10,606,000 Related loan balances:                                        Ending balance $254,708,000  $30,828,000  $85,467,000  $15,961,000  $358,394,000  $6,451,000  $103,372,000  $15,711,000  $-  $870,892,000 Ending balance specifically evaluated for impairment $14,295,000  $2,093,000  $3,886,000  $-  $18,054,000  $1,454,000  $1,336,000  $15,000  $-  $41,133,000 Ending balance collectively evaluated for impairment $240,413,000  $28,735,000  $81,581,000  $15,961,000  $340,340,000  $4,997,000  $102,036,000  $15,696,000  $-  $829,759,000  For the year ended Commercial  Municipal  Residential  Home Equity  Consumer  Unallocated  Total December 31, 2011 Real Estate  Construction  Other     Term  Construction  Line of Credit          Allowance for loan losses:                              Beginning balance $5,260,000  $1,012,000  $2,377,000  $19,000  $1,408,000  $44,000  $670,000  $646,000  $1,880,000  $13,316,000 Charge offs  1,619,000   346,000   6,492,000   -   1,421,000   505,000   415,000   381,000   -   11,179,000 Recoveries  23,000   -   60,000   -   7,000   -   1,000   222,000   -   313,000 Provision  1,995,000   (8,000)  6,118,000   -   1,165,000   716,000   339,000   97,000   128,000   10,550,000 Ending balance $5,659,000  $658,000  $2,063,000  $19,000  $1,159,000  $255,000  $595,000  $584,000  $2,008,000  $13,000,000 Ending balance specifically evaluated for impairment $808,000  $33,000  $402,000  $-  $478,000  $235,000  $91,000  $11,000  $-  $2,058,000 Ending balance collectively evaluated for impairment $4,851,000  $625,000  $1,661,000  $19,000  $681,000  $20,000  $504,000  $573,000  $2,008,000  $10,942,000 Related loan balances:                                        Ending balance $255,424,000  $32,574,000  $86,982,000  $16,221,000  $341,286,000  $10,469,000  $105,244,000  $16,788,000  $-  $864,988,000 Ending balance specifically evaluated for impairment $10,141,000  $5,702,000  $7,042,000  $-  $16,821,000  $1,198,000  $1,163,000  $53,000  $-  $42,120,000 Ending balance collectively evaluated for impairment $245,283,000  $26,872,000  $79,940,000  $16,221,000  $324,465,000  $9,271,000  $104,081,000  $16,735,000  $-  $822,868,000  For the three months ended Commercial  Municipal  Residential  Home Equity  Consumer  Unallocated  Total March 31, 2011 Real Estate  Construction  Other     Term  Construction  Line of Credit          Allowance for loan losses:                              Beginning balance $5,260,000  $1,012,000  $2,377,000  $19,000  $1,408,000  $44,000  $670,000  $646,000  $1,880,000  $13,316,000 Charge offs  289,000   -   161,000   -   457,000   505,000   1,000   100,000   -   1,513,000 Recoveries  5,000   -   17,000   -   3,000   -   -   72,000   -   97,000 Provision  1,334,000   (373,000)  302,000   -   451,000   607,000   9,000   95,000   (325,000)  2,100,000 Ending balance $6,310,000  $639,000  $2,535,000  $19,000  $1,405,000  $146,000  $678,000  $713,000  $1,555,000  $14,000,000 Ending balance specifically evaluated for impairment $593,000  $-  $326,000  $-  $381,000  $106,000  $139,000  $76,000  $-  $1,621,000 Ending balance collectively evaluated for impairment $5,717,000  $639,000  $2,209,000  $19,000  $1,024,000  $40,000  $539,000  $637,000  $1,555,000  $12,379,000 Related loan balances:                                        Ending balance $263,800,000  $29,316,000  $101,762,000  $20,834,000  $340,841,000  $13,370,000  $106,172,000  $18,589,000  $-  $894,684,000 Ending balance specifically evaluated for impairment $7,482,000  $813,000  $1,604,000  $-  $13,948,000  $2,248,000  $604,000  $115,000  $-  $26,814,000 Ending balance collectively evaluated for impairment $256,318,000  $28,503,000  $100,158,000  $20,834,000  $326,893,000  $11,122,000  $105,568,000  $18,474,000  $-  $867,870,000  |
| Troubled debt restructurings by class and specific reserve                  | The following table shows TDRs by class and the specific reserve as of March 31, 2012:   Number of Loans  Balance  Specific Reserves Commercial            Real estate  12  $7,610,000  $271,000    Construction  1   1,148,000   -    Other  12   1,919,000   85,000 Municipal  -   -   - Residential               Term  46   9,970,000   250,000    Construction  -   -   - Home equity line of credit  -   -   - Consumer  -   -   - Unallocated  -   -   -     71  $20,647,000  $606,000 As of March 31, 2012, 11 of the loans classified as TDRs with a total balance of $2,258,000 were more than 30 days past due. Of these loans, 7 loans with an outstanding balance of $1,733,000 had been placed on TDR status in the previous 12 months. The following table shows these TDRs by class and the associated specific reserves included in the allowance for loan losses as of March 31, 2012:   Number of Loans  Balance  Specific Reserves Commercial            Real estate  -  $-  $-    Construction  -   -   -    Other  4   667,000   44,000 Municipal  -   -   - Residential               Term  7   1,591,000   29,000    Construction  -   -   - Home equity line of credit  -   -   - Consumer  -   -   - Unallocated  -   -   -     11  $2,258,000  $73,000                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    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| Loans placed on troubled debt restructurings by class and specific reserve  | The following table shows loans placed on TDR status by class of loan and the associated specific reserve included in the allowance for loan losses as of March 31, 2012:   Number of Loans  Pre-ModificationOutstandingRecorded Investment  Post-Modification OutstandingRecordedInvestment  Specific Reserves Commercial               Real estate  7  $2,438,000  $2,404,000  $-    Construction  -   -   -   -    Other  3   12,000   12,000   - Municipal  -   -   -   - Residential                   Term  4   557,000   557,000   16,000    Construction  -   -   -   - Home equity line of credit  -   -   -   - Consumer  -   -   -   - Unallocated  -   -   -   -     14  $3,007,000  $2,973,000  $16,000                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             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| - Definition
Tabular disclosure for the roll forward of change in allowance for loan losses from period to period and related loan balances.
+ References
No definition available.
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| - Definition
Tabular disclosure of loans placed on troubled debt restructurings status by type of loan and the associated specific reserve included in the allowance for loan losses.
+ References
No definition available.
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| - Definition
Tabular disclosure of financing receivables (examples of financing receivables include loans, trade accounts receivable and notes receivable) and activity in the allowance for credit losses account.
+ References
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| - Definition
Tabular disclosure of financing receivables by credit quality indicator. The credit quality indicator is a statistic about the credit quality of financing receivables. Examples include, but not limited to, consumer credit risk scores, credit-rating-agency ratings, an entity's internal credit risk grades, loan-to-value ratios, collateral, collection experience and other internal metrics.
+ References
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|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Tabular disclosure of financing receivables and troubled debt restructurings.
+ References
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