LOANS AND ALLOWANCE FOR LOAN LOSSES (Narrative) (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2017 USD ($) loan	Sep. 30, 2016 USD ($) loan	Sep. 30, 2017 USD ($) loan	Sep. 30, 2016 USD ($) loan	Jun. 30, 2017 USD ($)	Dec. 31, 2016 USD ($)	Jun. 30, 2016 USD ($)	Dec. 31, 2015 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-Accrual Loans	$ 14,646,000		$ 14,646,000			$ 20,713,000
Other industry exposures			0
Interest lost on nonaccrual loans	$ 187,000	$ 251,000	$ 673,000	$ 675,000
Number of TDRs | loan	3	6	5	6
Loans modified | loan	0	0	0	0
Financing Receivable, Individually Evaluated for Impairment	$ 13,430,000	$ 20,682,000	$ 13,430,000	$ 20,682,000		20,254,000
Proceeds from the sale of mortgage loans			155,086,000	170,765,000
Gain on sale of mortgage loans			4,323,000	4,171,000
Loans held for sale, at fair value	12,997,000		12,997,000			14,836,000
Financing Receivable, Allowance for Credit Losses	24,413,000	23,290,000	24,413,000	23,290,000	$ 24,394,000	23,116,000	$ 23,717,000	$ 21,166,000
FHLB advances, general debt obligations, pledged collateral	1,100,000,000		1,100,000,000			1,100,000,000
Derivative, Fair Value, Net	313,000		313,000			278,000
Unrealized Gain (Loss) on Derivatives	60,000	226,000	283,000	610,000
Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans restructured due to credit difficulties that are now performing	5,200,000		5,200,000			4,300,000
Financing receivables impaired TDR non-performing	1,300,000		1,300,000			1,400,000
Residential Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-Accrual Loans	4,465,000		4,465,000			3,945,000
Financing Receivable, Individually Evaluated for Impairment	4,792,000	4,551,000	4,792,000	4,551,000		4,348,000
Mortgage Loans in Process of Foreclosure, Amount	2,200,000		2,200,000			1,400,000
Financing Receivable, Allowance for Credit Losses	4,542,000	4,595,000	4,542,000	4,595,000	4,481,000	4,160,000	4,431,000	4,545,000
Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-Accrual Loans	5,887,000		5,887,000			12,849,000
Financing Receivable, Individually Evaluated for Impairment	6,373,000	13,286,000	6,373,000	13,286,000		13,317,000
Financing Receivable, Allowance for Credit Losses	12,796,000	12,580,000	12,796,000	12,580,000	12,848,000	12,154,000	11,559,000	10,432,000
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-Accrual Loans	1,830,000		1,830,000			2,088,000
Financing Receivable, Individually Evaluated for Impairment	1,842,000	2,243,000	1,842,000	2,243,000		2,028,000
Financing Receivable, Allowance for Credit Losses	4,221,000	3,283,000	4,221,000	3,283,000	4,275,000	3,755,000	4,558,000	3,241,000
Home Equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-Accrual Loans	1,626,000		1,626,000			1,620,000
Financing Receivable, Individually Evaluated for Impairment	423,000	489,000	423,000	489,000		457,000
Financing Receivable, Allowance for Credit Losses	2,177,000	2,567,000	2,177,000	2,567,000	2,094,000	2,194,000	2,946,000	2,731,000
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-Accrual Loans	0		0			4,000
Financing Receivable, Individually Evaluated for Impairment	0	7,000	0	7,000		7,000
Financing Receivable, Allowance for Credit Losses	195,000	162,000	195,000	162,000	182,000	181,000	193,000	193,000
HPFC Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-Accrual Loans	838,000		838,000			207,000
Financing Receivable, Individually Evaluated for Impairment	0	106,000	0	106,000		97,000
Financing Receivable, Allowance for Credit Losses	482,000	103,000	482,000	103,000	$ 514,000	672,000	$ 30,000	$ 24,000
Fixed Rate Residential Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from the sale of mortgage loans	59,900,000	71,400,000	150,800,000	166,600,000
Gain on sale of mortgage loans	1,600,000	2,000,000	4,300,000	4,200,000
Loans held for sale, at fair value	13,000,000		13,000,000			15,100,000
Nonoperating Income (Expense) | Fixed Rate Residential Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gain on sale of mortgage loans	$ 72,000	(55,000)	263,000	99,000
Unrealized gain (loss) on loans held for sale			$ 26,000	289,000
Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Individually Evaluated for Impairment						250,000
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)			27.00%
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	313,000		313,000			$ 278,000
Unrealized Gain (Loss) on Derivatives	$ 16,000	$ 0	$ 35,000	$ 0