LOANS AND ALLOWANCE FOR LOAN LOSSES (Summary of Impaired Loan Balances and Associated Allowance by Portfolio Segment) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Financing Receivable, Impaired [Line Items]
Recorded Investment - with an allowance recorded	$ 8,851	$ 14,803	$ 8,851	$ 14,803	$ 14,858
Unpaid Principal Balance - with an allowance recorded	8,851	14,803	8,851	14,803	14,858
Related Allowance	1,934	1,957	1,934	1,957	2,007
Average Recorded Investment - with an allowance recorded	9,866	12,752	13,373	7,620	9,418
Interest Income Recognized - with an allowance recorded	52	56	118	81	106
Recorded Investment - without allowance recorded	4,579	5,879	4,579	5,879	5,396
Unpaid Principal Balance - without allowance recorded	6,478	9,474	6,478	9,474	7,756
Impaired Financing Receivable With No Related Allowance Related Allowance	0	0	0	0
Average Recorded Investment - without allowance recorded	4,552	5,295	4,832	7,424	6,970
Interest Income Recognized - without allowance recorded	21	36	51	56	76
Impaired Financing Receivable, Recorded Investment	13,430	20,682	13,430	20,682	20,254
Impaired financing receivable, unpaid principal balance	15,329	24,277	15,329	24,277	22,614
Impaired Financing Receivable, Average Recorded Investment	14,418	18,047	18,205	15,044	16,388
Impaired Financing Receivable, Interest Income, Accrual Method	73	92	169	137	182
Residential Real Estate
Financing Receivable, Impaired [Line Items]
Recorded Investment - with an allowance recorded	3,262	3,041	3,262	3,041	3,019
Unpaid Principal Balance - with an allowance recorded	3,262	3,041	3,262	3,041	3,019
Related Allowance	464	511	464	511	483
Average Recorded Investment - with an allowance recorded	3,194	3,050	3,084	3,108	3,088
Interest Income Recognized - with an allowance recorded	48	56	103	81	106
Recorded Investment - without allowance recorded	1,530	1,510	1,530	1,510	1,329
Unpaid Principal Balance - without allowance recorded	1,949	1,996	1,949	1,996	1,800
Impaired Financing Receivable With No Related Allowance Related Allowance	0	0	0	0
Average Recorded Investment - without allowance recorded	1,427	1,731	1,349	2,275	2,057
Interest Income Recognized - without allowance recorded	15	7	15	7	9
Commercial Real Estate
Financing Receivable, Impaired [Line Items]
Recorded Investment - with an allowance recorded	5,589	11,354	5,589	11,354	11,443
Unpaid Principal Balance - with an allowance recorded	5,589	11,354	5,589	11,354	11,443
Related Allowance	1,470	1,284	1,470	1,284	1,373
Average Recorded Investment - with an allowance recorded	6,590	7,582	10,048	3,092	5,165
Interest Income Recognized - with an allowance recorded	4		15
Recorded Investment - without allowance recorded	784	1,932	784	1,932	1,874
Unpaid Principal Balance - without allowance recorded	1,032	2,427	1,032	2,427	2,369
Impaired Financing Receivable With No Related Allowance Related Allowance	0	0	0	0
Average Recorded Investment - without allowance recorded	794	2,015	1,250	2,322	2,214
Interest Income Recognized - without allowance recorded	15	33	22	37	51
Commercial
Financing Receivable, Impaired [Line Items]
Recorded Investment - with an allowance recorded	0	0	0	0	0
Unpaid Principal Balance - with an allowance recorded	0	0	0	0	0
Related Allowance	0	0	0	0	0
Average Recorded Investment - with an allowance recorded	82	1,782	41	1,016	762
Recorded Investment - without allowance recorded	1,842	2,243	1,842	2,243	2,028
Unpaid Principal Balance - without allowance recorded	3,015	4,667	3,015	4,667	3,209
Impaired Financing Receivable With No Related Allowance Related Allowance	0	0	0	0
Average Recorded Investment - without allowance recorded	1,891	1,354	1,959	2,639	2,507
Interest Income Recognized - without allowance recorded	(6)	(11)	8	12	16
Home Equity
Financing Receivable, Impaired [Line Items]
Recorded Investment - with an allowance recorded	0	302	0	302	299
Unpaid Principal Balance - with an allowance recorded	0	302	0	302	299
Related Allowance	0	88	0	88	86
Average Recorded Investment - with an allowance recorded		303	167	307	305
Recorded Investment - without allowance recorded	423	187	423	187	158
Unpaid Principal Balance - without allowance recorded	482	374	482	374	368
Impaired Financing Receivable With No Related Allowance Related Allowance	0	0	0	0
Average Recorded Investment - without allowance recorded	440	188	271	181	180
Interest Income Recognized - without allowance recorded	1	3	6
Consumer
Financing Receivable, Impaired [Line Items]
Recorded Investment - with an allowance recorded	0	0	0	0	0
Unpaid Principal Balance - with an allowance recorded	0	0	0	0	0
Related Allowance	0	0	0	0	0
Average Recorded Investment - with an allowance recorded					0
Recorded Investment - without allowance recorded	0	7	0	7	7
Unpaid Principal Balance - without allowance recorded	0	10	0	10	10
Impaired Financing Receivable With No Related Allowance Related Allowance	0	0	0	0
Average Recorded Investment - without allowance recorded		7	3	7	12
Interest Income Recognized - without allowance recorded	(4)	4
HPFC Portfolio Segment
Financing Receivable, Impaired [Line Items]
Recorded Investment - with an allowance recorded	0	106	0	106	97
Unpaid Principal Balance - with an allowance recorded	0	106	0	106	97
Related Allowance	0	74	0	74	65
Average Recorded Investment - with an allowance recorded		35	33	97	98
Recorded Investment - without allowance recorded	0	0	0	0	0
Unpaid Principal Balance - without allowance recorded	0	0	0	0	0
Impaired Financing Receivable With No Related Allowance Related Allowance	$ 0	$ 0	$ 0	$ 0
Average Recorded Investment - without allowance recorded					$ 0

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