LOANS AND ALLOWANCE FOR LOAN LOSSES (Loan Aging Analysis by Portfolio Segment) (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	Dec. 31, 2016 USD ($)
Financing Receivable, Recorded Investment, Past Due [Line Items]
Number of TDRs | loan	3	6	5	6
Total Past Due	$ 21,622,000		$ 21,622,000		$ 25,465,000
Current	2,726,668,000		2,726,668,000		2,569,099,000
Total Loans Outstanding	2,748,290,000	$ 2,592,009,000	2,748,290,000	$ 2,592,009,000	2,594,564,000
Loans 90 Days Past Due and Accruing	0		0		0
Non-Accrual Loans	14,646,000		14,646,000		20,713,000
Financing Receivable, Modifications, Pre-Modification Recorded Investment	429,000	1,344,000	895,000	1,344,000
Financing Receivable, Modifications, Post-Modification Recorded Investment	448,000	1,652,000	914,000	1,652,000
Allowance Related to Troubled Debt Restructurings assigned during period	29,000	0	44,000	0
Residential Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	6,858,000		6,858,000		5,611,000
Current	845,993,000		845,993,000		796,883,000
Total Loans Outstanding	852,851,000	797,036,000	852,851,000	797,036,000	802,494,000
Loans 90 Days Past Due and Accruing	0		0		0
Non-Accrual Loans	4,465,000		4,465,000		3,945,000
Commercial Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	8,057,000		8,057,000		13,703,000
Current	1,123,826,000		1,123,826,000		1,037,077,000
Total Loans Outstanding	1,131,883,000	1,054,307,000	1,131,883,000	1,054,307,000	1,050,780,000
Loans 90 Days Past Due and Accruing	0		0		0
Non-Accrual Loans	5,887,000		5,887,000		12,849,000
Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,205,000		2,205,000		2,526,000
Current	366,950,000		366,950,000		331,113,000
Total Loans Outstanding	369,155,000	324,422,000	369,155,000	324,422,000	333,639,000
Loans 90 Days Past Due and Accruing	0		0		0
Non-Accrual Loans	1,830,000		1,830,000		2,088,000
Home Equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,681,000		2,681,000		2,347,000
Current	325,647,000		325,647,000		327,560,000
Total Loans Outstanding	328,328,000	333,095,000	328,328,000	333,095,000	329,907,000
Loans 90 Days Past Due and Accruing	0		0		0
Non-Accrual Loans	1,626,000		1,626,000		1,620,000
Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	44,000		44,000		42,000
Current	18,079,000		18,079,000		17,290,000
Total Loans Outstanding	18,123,000	17,416,000	18,123,000	17,416,000	17,332,000
Loans 90 Days Past Due and Accruing	0		0		0
Non-Accrual Loans	0		0		4,000
HPFC Portfolio Segment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,777,000		1,777,000		1,236,000
Current	46,173,000		46,173,000		59,176,000
Total Loans Outstanding	47,950,000	$ 65,733,000	47,950,000	$ 65,733,000	60,412,000
Loans 90 Days Past Due and Accruing	0		0		0
Non-Accrual Loans	838,000		838,000		207,000
30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	6,762,000		6,762,000		4,639,000
30-59 Days Past Due | Residential Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	3,308,000		3,308,000		1,783,000
30-59 Days Past Due | Commercial Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,036,000		1,036,000		855,000
30-59 Days Past Due | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	721,000		721,000		633,000
30-59 Days Past Due | Home Equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,022,000		1,022,000		892,000
30-59 Days Past Due | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	29,000		29,000		38,000
30-59 Days Past Due | HPFC Portfolio Segment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	646,000		646,000		438,000
60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,550,000		2,550,000		2,187,000
60-89 Days Past Due | Residential Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	157,000		157,000		924,000
60-89 Days Past Due | Commercial Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,260,000		1,260,000		223,000
60-89 Days Past Due | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0		0		218,000
60-89 Days Past Due | Home Equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	284,000		284,000		134,000
60-89 Days Past Due | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	15,000		15,000		0
60-89 Days Past Due | HPFC Portfolio Segment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	834,000		834,000		688,000
Greater than 90 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	12,310,000		12,310,000		18,639,000
Greater than 90 Days | Residential Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	3,393,000		3,393,000		2,904,000
Greater than 90 Days | Commercial Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	5,761,000		5,761,000		12,625,000
Greater than 90 Days | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,484,000		1,484,000		1,675,000
Greater than 90 Days | Home Equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,375,000		1,375,000		1,321,000
Greater than 90 Days | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0		0		4,000
Greater than 90 Days | HPFC Portfolio Segment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 297,000		$ 297,000		$ 110,000
Commercial | Extended Maturity [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Number of TDRs | loan	0	6	0	6
Financing Receivable, Modifications, Pre-Modification Recorded Investment	$ 0	$ 1,344,000	$ 0	$ 1,344,000
Financing Receivable, Modifications, Post-Modification Recorded Investment	0	1,652,000	0	1,652,000
Allowance Related to Troubled Debt Restructurings assigned during period	$ 0	$ 0	$ 0	$ 0