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LOANS AND ALLOWANCE FOR LOAN LOSSES (Narrative) (Details) | 3 Months Ended | 6 Months Ended |  |  |  |
--- | --- | --- | --- | --- | --- | ---
Jun. 30, 2018 USD ($) loan | Jun. 30, 2017 USD ($) loan | Jun. 30, 2018 USD ($) loan | Jun. 30, 2017 USD ($) loan | Mar. 31, 2018 USD ($) | Dec. 31, 2017 USD ($) | Mar. 31, 2017 USD ($) | Dec. 31, 2016 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |  |
Non-Accrual Loans | $ 15,810,000 |  | $ 15,810,000 |  |  | $ 15,314,000 |  |
Other industry exposures |  |  | 0 |  |  |  |  |
Interest lost on nonaccrual loans | $ 174,000 | $ 277,000 | $ 336,000 | $ 486,000 |  |  |  |
Number of TDRs | loan | 1 | 1 | 1 | 2 |  |  |  |
Loans modified | loan | 1 | 0 | 1 | 0 |  |  |  |
Financing Receivable, Modifications, Subsequent Default, Recorded Investment | $ 299,000 | $ 0 | $ 299,000 | $ 0 |  |  |  |
Financing Receivable, Individually Evaluated for Impairment | 12,591,000 | 20,080,000 | 12,591,000 | 20,080,000 |  | 13,590,000 |  |
Proceeds from the sale of mortgage loans |  |  | 99,778,000 | 93,557,000 |  |  |  |
Gain on sale of mortgage loans |  |  | 2,550,000 | 2,656,000 |  |  |  |
Loans held for sale, at fair value | 12,656,000 |  | 12,656,000 |  |  | 8,103,000 |  |
Financing Receivable, Allowance for Credit Losses | 23,668,000 | 24,394,000 | 23,668,000 | 24,394,000 | $ 22,990,000 | 24,171,000 | $ 23,721,000 | $ 23,116,000
FHLB advances, general debt obligations, pledged collateral | 1,100,000,000 |  | 1,100,000,000 |  |  | 1,100,000,000 |  |
Derivative, Fair Value, Net | 192,000 |  | 192,000 |  |  | 142,000 |  |
Unrealized Gain (Loss) on Derivatives | (4,000) | (235,000) | 8,000 | (223,000) |  |  |  |
Loans |  |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |  |
Loans restructured due to credit difficulties that are now performing | 4,000,000 |  | 4,000,000 |  |  | 5,000,000 |  |
Financing receivables impaired TDR non-performing | 1,500,000 |  | 1,500,000 |  |  | 1,200,000 |  |
Residential Real Estate |  |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |  |
Non-Accrual Loans | 5,742,000 |  | 5,742,000 |  |  | 4,979,000 |  |
Financing Receivable, Individually Evaluated for Impairment | 5,400,000 | 4,451,000 | 5,400,000 | 4,451,000 |  | 5,171,000 |  |
Mortgage Loans in Process of Foreclosure, Amount | 1,400,000 |  | 1,400,000 |  |  | 1,900,000 |  |
Financing Receivable, Allowance for Credit Losses | 5,779,000 | 4,481,000 | 5,779,000 | 4,481,000 | 5,497,000 | 5,086,000 | 4,271,000 | 4,160,000
Commercial Real Estate |  |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |  |
Non-Accrual Loans | 5,600,000 |  | 5,600,000 |  |  | 5,642,000 |  |
Financing Receivable, Individually Evaluated for Impairment | 5,093,000 | 13,116,000 | 5,093,000 | 13,116,000 |  | 6,199,000 |  |
Financing Receivable, Allowance for Credit Losses | 10,310,000 | 12,848,000 | 10,310,000 | 12,848,000 | 10,286,000 | 11,863,000 | 12,726,000 | 12,154,000
Commercial |  |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |  |
Non-Accrual Loans | 1,934,000 |  | 1,934,000 |  |  | 2,000,000 |  |
Financing Receivable, Individually Evaluated for Impairment | 1,611,000 | 2,067,000 | 1,611,000 | 2,067,000 |  | 1,791,000 |  |
Financing Receivable, Allowance for Credit Losses | 4,303,000 | 4,275,000 | 4,303,000 | 4,275,000 | 4,126,000 | 4,171,000 | 3,815,000 | 3,755,000
Home Equity |  |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |  |
Non-Accrual Loans | 1,680,000 |  | 1,680,000 |  |  | 1,650,000 |  |
Financing Receivable, Individually Evaluated for Impairment | 487,000 | 446,000 | 487,000 | 446,000 |  | 429,000 |  |
Financing Receivable, Allowance for Credit Losses | 2,616,000 | 2,094,000 | 2,616,000 | 2,094,000 | 2,427,000 | 2,367,000 | 2,107,000 | 2,194,000
Consumer |  |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |  |
Non-Accrual Loans | 20,000 |  | 20,000 |  |  | 0 |  |
Financing Receivable, Individually Evaluated for Impairment | 0 | 0 | 0 | 0 |  |  |  |
Financing Receivable, Allowance for Credit Losses | 260,000 | 182,000 | 260,000 | 182,000 | 230,000 | 233,000 | 175,000 | 181,000
HPFC Portfolio Segment |  |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |  |
Non-Accrual Loans | 834,000 |  | 834,000 |  |  | 1,043,000 |  |
Financing Receivable, Individually Evaluated for Impairment | 0 | 0 | 0 | 0 |  |  |  |
Financing Receivable, Allowance for Credit Losses | 400,000 | 514,000 | 400,000 | 514,000 | $ 424,000 | 451,000 | $ 627,000 | $ 672,000
Fixed Rate Residential Mortgage |  |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |  |
Proceeds from the sale of mortgage loans | 52,000,000 | 47,900,000 | 97,200,000 | 90,900,000 |  |  |  |
Gain on sale of mortgage loans | 1,300,000 | 1,400,000 | 2,600,000 | 2,700,000 |  |  |  |
Loans held for sale, at fair value | 12,600,000 |  | 12,600,000 |  |  | 8,100,000 |  |
Nonoperating Income (Expense) | Fixed Rate Residential Mortgage |  |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |  |
Gain on sale of mortgage loans | $ 23,000 | (63,000) | 32,000 | 191,000 |  |  |  |
Unrealized gain (loss) on loans held for sale |  |  | $ 69,000 | 37,000 |  |  |  |
Minimum |  |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |  |
Number of Months | 18 |  | 18 |  |  |  |  |
Minimum | HPFC Portfolio Segment |  |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |  |
Term to maturity | 7 years |  |  |  |  |  |  |
Maximum |  |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |  |
Number of Months | 24 |  | 24 |  |  |  |  |
Maximum | HPFC Portfolio Segment |  |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |  |
Term to maturity | 10 years |  |  |  |  |  |  |
Non-Residential Building Operators Industry Sector | Loan Concentration Risk | Total Loan Portfolio |  |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |  |
Concentration risk (percentage) |  |  | 11.00% |  |  |  |  |
Non-Residential Building Operators Industry Sector | Loan Concentration Risk | Commercial Real Estate |  |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |  |
Concentration risk (percentage) |  |  | 25.00% |  |  |  |  |
Substandard (Grade 8) | Minimum |  |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |  |
Financing Receivable, Individually Evaluated for Impairment | $ 500,000 |  | $ 500,000 |  |  |  |  |
Forward Contracts [Member] |  |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |  |
Derivative, Fair Value, Net | 192,000 |  | 192,000 |  |  | $ 142,000 |  |
Unrealized Gain (Loss) on Derivatives | $ 69,000 | $ 137,000 | $ 50,000 | $ 19,000 |  |  |  |

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Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_ForwardContractsMember
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Data Type: | na
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