LOANS AND ALLOWANCE FOR LOAN LOSSES (Activity in Allowance for Loan Losses by Portfolio Segment) (Details) - USD ($)		3 Months Ended		6 Months Ended		12 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Financing Receivable, Allowance for Credit Losses [Line Items]
Reserve for unfunded commitments		$ 22,000	$ 26,000	$ 22,000	$ 26,000	$ 22,000
Activity in ALL:
Beginning balance		21,339,000	21,265,000	21,166,000	21,116,000	21,116,000
Loans charged off		(626,000)	(474,000)	(1,427,000)	(898,000)	(2,616,000)
Recoveries		150,000	152,000	254,000	285,000	728,000
Provision (credit)(1)	[1]	2,854,000	251,000	3,724,000	691,000	1,938,000
Ending balance		23,717,000	21,194,000	23,717,000	21,194,000	21,166,000
Ending Balance: Individually evaluated for impairment		2,015,000	1,267,000	2,015,000	1,267,000	1,369,000
Ending Balance: Collectively evaluated for impairment		21,702,000	19,927,000	21,702,000	19,927,000	19,797,000
Ending Balance: Individually evaluated for impairment		11,237,000	10,539,000	11,237,000	10,539,000	15,235,000
Ending Balance: Collectively evaluated for impairment		2,574,063,000	1,796,468,000	2,574,063,000	1,796,468,000	2,474,971,000
Total Loans Outstanding		2,585,300,000	1,807,007,000	2,585,300,000	1,807,007,000	2,490,206,000
Residential Real Estate
Activity in ALL:
Beginning balance		4,516,000	4,835,000	4,545,000	4,899,000	4,899,000
Loans charged off		(19,000)	(179,000)	(229,000)	(292,000)	(801,000)
Recoveries		31,000	17,000	71,000	20,000	55,000
Provision (credit)(1)		(97,000)	16,000	44,000	62,000	392,000
Ending balance		4,431,000	4,689,000	4,431,000	4,689,000	4,545,000
Ending Balance: Individually evaluated for impairment		497,000	724,000	497,000	724,000	544,000
Ending Balance: Collectively evaluated for impairment		3,934,000	3,965,000	3,934,000	3,965,000	4,001,000
Ending Balance: Individually evaluated for impairment		4,926,000	5,562,000	4,926,000	5,562,000	6,026,000
Ending Balance: Collectively evaluated for impairment		795,630,000	581,682,000	795,630,000	581,682,000	814,591,000
Total Loans Outstanding		800,556,000	587,244,000	800,556,000	587,244,000	820,617,000
Commercial Real Estate
Activity in ALL:
Beginning balance		10,380,000	8,234,000	10,432,000	7,951,000	7,951,000
Loans charged off		(19,000)	(48,000)	(241,000)	(103,000)	(481,000)
Recoveries		34,000	54,000	43,000	64,000	74,000
Provision (credit)(1)		1,164,000	(80,000)	1,325,000	248,000	2,888,000
Ending balance		11,559,000	8,160,000	11,559,000	8,160,000	10,432,000
Ending Balance: Individually evaluated for impairment		29,000	240,000	29,000	240,000	644,000
Ending Balance: Collectively evaluated for impairment		11,530,000	7,920,000	11,530,000	7,920,000	9,788,000
Ending Balance: Individually evaluated for impairment		2,340,000	3,034,000	2,340,000	3,034,000	4,610,000
Ending Balance: Collectively evaluated for impairment		1,015,437,000	657,101,000	1,015,437,000	657,101,000	923,341,000
Total Loans Outstanding		1,017,777,000	660,135,000	1,017,777,000	660,135,000	927,951,000
Commercial
Activity in ALL:
Beginning balance		3,298,000	3,427,000	3,241,000	3,354,000	3,354,000
Loans charged off		(203,000)	(84,000)	(429,000)	(243,000)	(655,000)
Recoveries		82,000	78,000	134,000	182,000	389,000
Provision (credit)(1)		1,381,000	(106,000)	1,612,000	22,000	153,000
Ending balance		4,558,000	3,315,000	4,558,000	3,315,000	3,241,000
Ending Balance: Individually evaluated for impairment		1,400,000	136,000	1,400,000	136,000	92,000
Ending Balance: Collectively evaluated for impairment		3,158,000	3,179,000	3,158,000	3,179,000	3,149,000
Ending Balance: Individually evaluated for impairment		3,461,000	800,000	3,461,000	800,000	3,937,000
Ending Balance: Collectively evaluated for impairment		333,056,000	261,387,000	333,056,000	261,387,000	293,784,000
Total Loans Outstanding		336,517,000	262,187,000	336,517,000	262,187,000	297,721,000
Home Equity
Activity in ALL:
Beginning balance		2,622,000	2,247,000	2,731,000	2,247,000	2,247,000
Loans charged off		(57,000)	(152,000)	(185,000)	(241,000)	(525,000)
Recoveries		1,000	0	2,000	5,000	188,000
Provision (credit)(1)		380,000	49,000	398,000	133,000	821,000
Ending balance		2,946,000	2,144,000	2,946,000	2,144,000	2,731,000
Ending Balance: Individually evaluated for impairment		89,000	89,000	89,000	89,000	89,000
Ending Balance: Collectively evaluated for impairment		2,857,000	2,055,000	2,857,000	2,055,000	2,642,000
Ending Balance: Individually evaluated for impairment		503,000	986,000	503,000	986,000	588,000
Ending Balance: Collectively evaluated for impairment		341,478,000	280,071,000	341,478,000	280,071,000	348,046,000
Total Loans Outstanding		341,981,000	281,057,000	341,981,000	281,057,000	348,634,000
Consumer
Activity in ALL:
Beginning balance		182,000	270,000	193,000	281,000	281,000
Loans charged off		(26,000)	(11,000)	(41,000)	(19,000)	(154,000)
Recoveries		2,000	3,000	4,000	14,000	22,000
Provision (credit)(1)		35,000	6,000	37,000	(8,000)	44,000
Ending balance		193,000	268,000	193,000	268,000	193,000
Ending Balance: Individually evaluated for impairment		0	78,000	0	78,000	0
Ending Balance: Collectively evaluated for impairment		193,000	190,000	193,000	190,000	193,000
Ending Balance: Individually evaluated for impairment		7,000	157,000	7,000	157,000	74,000
Ending Balance: Collectively evaluated for impairment		17,811,000	16,227,000	17,811,000	16,227,000	17,879,000
Total Loans Outstanding		17,818,000	16,384,000	17,818,000	16,384,000	17,953,000
HPFC Portfolio Segment [Member]
Activity in ALL:
Beginning balance		341,000	0	24,000	0	0
Loans charged off		(302,000)	0	(302,000)	0	0
Recoveries		0	0	0	0	0
Provision (credit)(1)		(9,000)	0	308,000	0	24,000
Ending balance		30,000	0	30,000	0	24,000
Ending Balance: Individually evaluated for impairment		0	0	0	0	0
Ending Balance: Collectively evaluated for impairment		30,000	0	30,000	0	24,000
Ending Balance: Individually evaluated for impairment		0	0	0	0	0
Ending Balance: Collectively evaluated for impairment		70,651,000	0	70,651,000	0	77,330,000
Total Loans Outstanding		70,651,000	0	70,651,000	0	77,330,000
Unallocated
Activity in ALL:
Beginning balance		0	2,252,000	0	2,384,000	2,384,000
Loans charged off		0	0	0	0	0
Recoveries		0	0	0	0	0
Provision (credit)(1)		0	366,000	0	234,000	(2,384,000)
Ending balance		0	2,618,000	0	2,618,000	0
Ending Balance: Individually evaluated for impairment		0	0	0	0	0
Ending Balance: Collectively evaluated for impairment		0	2,618,000	0	2,618,000	0
Ending Balance: Individually evaluated for impairment		0	0	0	0	0
Ending Balance: Collectively evaluated for impairment		0	0	0	0	0
Total Loans Outstanding		$ 0	$ 0	$ 0	$ 0	$ 0

[1] (1) The provision (credit) for loan losses excludes any impact for the change in the reserve for unfunded commitments, which represents management's estimate of the amount required to reflect the probable inherent losses on outstanding letters of credit and unused lines of credit. The reserve for unfunded commitments is presented within accrued interest and other liabilities on the consolidated statements of condition. At June 30, 2016 and 2015, and December 31, 2015, the reserve for unfunded commitments was $22,000, $26,000 and $22,000, respectively.