LOANS AND ALLOWANCE FOR LOAN LOSSES (Summary of Impaired Loan Balances and Associated Allowance by Portfolio Segment) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Financing Receivable, Impaired [Line Items]
Recorded Investment - with an allowance recorded	$ 4,413	$ 7,282	$ 4,476
Unpaid Principal Balance - with an allowance recorded	4,413	7,282	4,476
Related Allowance	927	1,033	824
Average Recorded Investment - with an allowance recorded	4,444	8,069	5,921
Interest Income Recognized - with an allowance recorded	31	31	138
Recorded Investment - without allowance recorded	1,851	3,943	2,450
Unpaid Principal Balance - without allowance recorded	2,412	5,859	3,001
Impaired Financing Receivable With No Related Allowance Related Allowance	0	0
Average Recorded Investment - without allowance recorded	2,147	4,123	5,368
Interest Income Recognized - without allowance recorded	15	14	55
Impaired Financing Receivable, Recorded Investment	6,264	11,225	6,926
Impaired financing receivable, unpaid principal balance	6,825	13,141	7,477
Impaired Financing Receivable, Average Recorded Investment	6,591	12,192	11,289
Impaired Financing Receivable, Interest Income, Accrual Method	46	45	193
Residential Real Estate
Financing Receivable, Impaired [Line Items]
Recorded Investment - with an allowance recorded	3,454	3,544	3,471
Unpaid Principal Balance - with an allowance recorded	3,454	3,544	3,471
Related Allowance	553	553	586
Average Recorded Investment - with an allowance recorded	3,462	3,745	3,591
Interest Income Recognized - with an allowance recorded	30	30	127
Recorded Investment - without allowance recorded	1,282	1,515	1,291
Unpaid Principal Balance - without allowance recorded	1,406	1,791	1,415
Impaired Financing Receivable With No Related Allowance Related Allowance	0	0
Average Recorded Investment - without allowance recorded	1,286	1,350	1,524
Interest Income Recognized - without allowance recorded	10	7	34
Commercial Real Estate
Financing Receivable, Impaired [Line Items]
Recorded Investment - with an allowance recorded	131	3,591	131
Unpaid Principal Balance - with an allowance recorded	131	3,591	131
Related Allowance	27	368	23
Average Recorded Investment - with an allowance recorded	131	4,275	1,969
Interest Income Recognized - with an allowance recorded	1	1	11
Recorded Investment - without allowance recorded	279	370	799
Unpaid Principal Balance - without allowance recorded	455	677	975
Impaired Financing Receivable With No Related Allowance Related Allowance	0	0
Average Recorded Investment - without allowance recorded	539	637	2,269
Interest Income Recognized - without allowance recorded	3	3	13
Commercial
Financing Receivable, Impaired [Line Items]
Recorded Investment - with an allowance recorded	0	0	556
Unpaid Principal Balance - with an allowance recorded	0	0	556
Related Allowance	0	0	53
Average Recorded Investment - with an allowance recorded	278		111
Recorded Investment - without allowance recorded	223	1,714	230
Unpaid Principal Balance - without allowance recorded	286	2,923	293
Impaired Financing Receivable With No Related Allowance Related Allowance	0	0
Average Recorded Investment - without allowance recorded	226	1,740	1,379
Interest Income Recognized - without allowance recorded	2	2	8
Home Equity
Financing Receivable, Impaired [Line Items]
Recorded Investment - with an allowance recorded	828	147	318
Unpaid Principal Balance - with an allowance recorded	828	147	318
Related Allowance	347	112	162
Average Recorded Investment - with an allowance recorded	573	49	250
Recorded Investment - without allowance recorded	67	344	124
Unpaid Principal Balance - without allowance recorded	265	468	305
Impaired Financing Receivable With No Related Allowance Related Allowance	0	0
Average Recorded Investment - without allowance recorded	96	396	195
Interest Income Recognized - without allowance recorded		2
Consumer
Financing Receivable, Impaired [Line Items]
Recorded Investment - with an allowance recorded	0	0	0
Unpaid Principal Balance - with an allowance recorded	0	0	0
Related Allowance	0	0	0
Average Recorded Investment - with an allowance recorded			0
Recorded Investment - without allowance recorded	0	0	6
Unpaid Principal Balance - without allowance recorded	0	0	13
Impaired Financing Receivable With No Related Allowance Related Allowance	0	0
Average Recorded Investment - without allowance recorded			1
HPFC Portfolio Segment
Financing Receivable, Impaired [Line Items]
Recorded Investment - with an allowance recorded	0	0	0
Unpaid Principal Balance - with an allowance recorded	0	0	0
Related Allowance	0	0	0
Average Recorded Investment - with an allowance recorded			0
Recorded Investment - without allowance recorded	0	0	0
Unpaid Principal Balance - without allowance recorded	0	0	0
Impaired Financing Receivable With No Related Allowance Related Allowance	$ 0	$ 0
Average Recorded Investment - without allowance recorded			$ 0

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Topic 310
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-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5258-111524

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