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, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Financing Receivable, Allowance for Credit Loss [Line Items]
Reserve for unfunded commitments	$ 22,000	$ 14,000	$ 22,000	$ 14,000	$ 21,000
Activity in ALL:
Beginning balance	26,521,000	25,201,000	25,171,000	24,712,000	24,712,000
Loans charged off	(484,000)	(271,000)	(974,000)	(607,000)	(2,713,000)
Recoveries	102,000	58,000	170,000	133,000	310,000
Provision (credit)(1)	9,400,000	1,175,000	11,172,000	1,925,000	2,862,000
Ending balance	35,539,000	26,163,000	35,539,000	26,163,000	25,171,000
Ending Balance: Individually evaluated for impairment	462,000	1,183,000	462,000	1,183,000	463,000
Ending Balance: Collectively evaluated for impairment	35,077,000	24,980,000	35,077,000	24,980,000	24,708,000
Ending Balance: Individually evaluated for impairment	4,163,000	6,443,000	4,163,000	6,443,000	4,478,000
Ending Balance: Collectively evaluated for impairment	3,321,878,000	3,093,881,000	3,321,878,000	3,093,881,000	3,090,545,000
Total Loans Outstanding	3,326,041,000	3,100,324,000	3,326,041,000	3,100,324,000	3,095,023,000
Residential Real Estate
Activity in ALL:
Beginning balance	5,897,000	6,153,000	5,842,000	6,071,000	6,071,000
Loans charged off	0	(14,000)	(96,000)	(25,000)	(462,000)
Recoveries	21,000	2,000	23,000	4,000	16,000
Provision (credit)(1)	2,685,000	108,000	2,834,000	199,000	217,000
Ending balance	8,603,000	6,249,000	8,603,000	6,249,000	5,842,000
Ending Balance: Individually evaluated for impairment	338,000	524,000	338,000	524,000	364,000
Ending Balance: Collectively evaluated for impairment	8,265,000	5,725,000	8,265,000	5,725,000	5,478,000
Ending Balance: Individually evaluated for impairment	3,153,000	4,472,000	3,153,000	4,472,000	3,384,000
Ending Balance: Collectively evaluated for impairment	1,051,180,000	1,031,320,000	1,051,180,000	1,031,320,000	1,066,990,000
Total Loans Outstanding	1,054,333,000	1,035,792,000	1,054,333,000	1,035,792,000	1,070,374,000
Commercial Real Estate
Activity in ALL:
Beginning balance	13,374,000	11,838,000	12,414,000	11,654,000	11,654,000
Loans charged off	(21,000)	0	(71,000)	(65,000)	(300,000)
Recoveries	3,000	3,000	7,000	7,000	49,000
Provision (credit)(1)	5,030,000	311,000	6,036,000	556,000	1,011,000
Ending balance	18,386,000	12,152,000	18,386,000	12,152,000	12,414,000
Ending Balance: Individually evaluated for impairment	35,000	27,000	35,000	27,000	30,000
Ending Balance: Collectively evaluated for impairment	18,351,000	12,125,000	18,351,000	12,125,000	12,384,000
Ending Balance: Individually evaluated for impairment	461,000	409,000	461,000	409,000	402,000
Ending Balance: Collectively evaluated for impairment	1,310,524,000	1,260,230,000	1,310,524,000	1,260,230,000	1,242,995,000
Total Loans Outstanding	1,310,985,000	1,260,639,000	1,310,985,000	1,260,639,000	1,243,397,000
Commercial
Activity in ALL:
Beginning balance	4,114,000	3,616,000	3,769,000	3,620,000	3,620,000
Loans charged off	(420,000)	(217,000)	(673,000)	(453,000)	(1,167,000)
Recoveries	63,000	49,000	116,000	111,000	225,000
Provision (credit)(1)	922,000	659,000	1,467,000	829,000	1,091,000
Ending balance	4,679,000	4,107,000	4,679,000	4,107,000	3,769,000
Ending Balance: Individually evaluated for impairment	0	322,000	0	322,000
Ending Balance: Collectively evaluated for impairment	4,679,000	3,785,000	4,679,000	3,785,000	3,769,000
Ending Balance: Individually evaluated for impairment	179,000	675,000	179,000	675,000	319,000
Ending Balance: Collectively evaluated for impairment	411,046,000	428,001,000	411,046,000	428,001,000	420,789,000
Total Loans Outstanding	411,225,000	428,676,000	411,225,000	428,676,000	421,108,000
SBA PPP Portfolio Segment
Activity in ALL:
Beginning balance	0	0	0	0	0
Loans charged off	0	0	0	0
Recoveries	0	0	0	0
Provision (credit)(1)	113,000	0	113,000	0
Ending balance	113,000	0	113,000	0	0
Ending Balance: Individually evaluated for impairment	0	0	0	0
Ending Balance: Collectively evaluated for impairment	113,000	0	113,000	0
Ending Balance: Individually evaluated for impairment	0	0	0	0
Ending Balance: Collectively evaluated for impairment	218,803,000	0	218,803,000	0
Total Loans Outstanding	218,803,000	0	218,803,000	0	0
Home Equity
Activity in ALL:
Beginning balance	2,480,000	3,027,000	2,423,000	2,796,000	2,796,000
Loans charged off	(17,000)	(34,000)	(51,000)	(44,000)	(412,000)
Recoveries	0	0	4,000	0	1,000
Provision (credit)(1)	621,000	(1,000)	708,000	240,000	38,000
Ending balance	3,084,000	2,992,000	3,084,000	2,992,000	2,423,000
Ending Balance: Individually evaluated for impairment	89,000	310,000	89,000	310,000	69,000
Ending Balance: Collectively evaluated for impairment	2,995,000	2,682,000	2,995,000	2,682,000	2,354,000
Ending Balance: Individually evaluated for impairment	370,000	887,000	370,000	887,000	373,000
Ending Balance: Collectively evaluated for impairment	290,445,000	322,649,000	290,445,000	322,649,000	312,406,000
Total Loans Outstanding	290,815,000	323,536,000	290,815,000	323,536,000	312,779,000
Consumer
Activity in ALL:
Beginning balance	473,000	259,000	507,000	234,000	234,000
Loans charged off	(26,000)	(6,000)	(83,000)	(20,000)	(301,000)
Recoveries	15,000	4,000	20,000	11,000	19,000
Provision (credit)(1)	42,000	126,000	60,000	158,000	555,000
Ending balance	504,000	383,000	504,000	383,000	507,000
Ending Balance: Individually evaluated for impairment	0	0	0	0
Ending Balance: Collectively evaluated for impairment	504,000	383,000	504,000	383,000	507,000
Ending Balance: Individually evaluated for impairment	0	0	0	0
Ending Balance: Collectively evaluated for impairment	22,919,000	23,665,000	22,919,000	23,665,000	25,772,000
Total Loans Outstanding	22,919,000	23,665,000	22,919,000	23,665,000	25,772,000
HPFC Portfolio Segment
Activity in ALL:
Beginning balance	183,000	308,000	216,000	337,000	337,000
Loans charged off	0	0	0	0	(71,000)
Recoveries	0	0	0	0
Provision (credit)(1)	(13,000)	(28,000)	(46,000)	(57,000)	(50,000)
Ending balance	170,000	280,000	170,000	280,000	216,000
Ending Balance: Individually evaluated for impairment	0	0	0	0
Ending Balance: Collectively evaluated for impairment	170,000	280,000	170,000	280,000	216,000
Ending Balance: Individually evaluated for impairment	0	0	0	0
Ending Balance: Collectively evaluated for impairment	16,961,000	28,016,000	16,961,000	28,016,000	21,593,000
Total Loans Outstanding	$ 16,961,000	$ 28,016,000	$ 16,961,000	$ 28,016,000	$ 21,593,000