LOANS AND ALLOWANCE FOR LOAN AND LEASE LOSSES - TDR MODIFICATIONS (Details)	3 Months Ended		9 Months Ended		12 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 ($) loan
Troubled Debt Restructurings disclosures
Period of time loans are not past due in which TDR loans are performing			30 days
Number of Loans | loan			287		308
Recorded Investment			$ 37,594,000		$ 41,586,000
Commitments to lend any additional material amounts to existing TDR relationships	$ 0		0		$ 0
Change between the pre and post modification loan	$ 0	$ 0	$ 0	$ 0
Residential Real Estate
Troubled Debt Restructurings disclosures
Number of Loans | loan			262		277
Recorded Investment			$ 27,302,000		$ 28,753,000
Residential Real Estate | Interest only payments
Troubled Debt Restructurings disclosures
Number of Loans | loan			2		3
Recorded Investment			$ 473,000		$ 648,000
Residential Real Estate | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | loan			190		205
Recorded Investment			$ 22,374,000		$ 24,338,000
Residential Real Estate | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan			20		14
Recorded Investment			$ 2,060,000		$ 922,000
Residential Real Estate | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | loan			50		55
Recorded Investment			$ 2,395,000		$ 2,845,000
Commercial Real Estate and Commercial Construction
Troubled Debt Restructurings disclosures
Number of Loans | loan			25		31
Recorded Investment			$ 10,292,000		$ 12,833,000
Commercial Real Estate and Commercial Construction | Interest only payments
Troubled Debt Restructurings disclosures
Number of Loans | loan			4		6
Recorded Investment			$ 1,243,000		$ 3,079,000
Commercial Real Estate and Commercial Construction | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | loan			9		10
Recorded Investment			$ 3,911,000		$ 4,997,000
Commercial Real Estate and Commercial Construction | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan			12		15
Recorded Investment			$ 5,138,000		$ 4,757,000
Modified During The Period
Troubled Debt Restructurings disclosures
Number of Loans | loan	15	8	18	19
Recorded Investment	$ 1,411,000	$ 2,389,000	$ 2,436,000	$ 2,936,000
Modified During The Period | Residential Real Estate
Troubled Debt Restructurings disclosures
Number of Loans | loan	14	5	17	16
Recorded Investment	$ 1,169,000	$ 660,000	$ 2,194,000	$ 1,207,000
Modified During The Period | Residential Real Estate | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | loan		1	1	8
Recorded Investment		$ 262,000	$ 220,000	$ 645,000
Modified During The Period | Residential Real Estate | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan	7		9
Recorded Investment	$ 701,000		$ 1,506,000
Modified During The Period | Residential Real Estate | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | loan	7	4	7	8
Recorded Investment	$ 468,000	$ 398,000	$ 468,000	$ 562,000
Modified During The Period | Commercial Real Estate and Commercial Construction
Troubled Debt Restructurings disclosures
Number of Loans | loan	1	3	1	3
Recorded Investment	$ 242,000	$ 1,729,000	$ 242,000	$ 1,729,000
Modified During The Period | Commercial Real Estate and Commercial Construction | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | loan		2		2
Recorded Investment		$ 225,000		$ 225,000
Modified During The Period | Commercial Real Estate and Commercial Construction | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan	1	1	1	1
Recorded Investment	$ 242,000	$ 1,504,000	$ 242,000	$ 1,504,000
Performing Financing Receivable
Troubled Debt Restructurings disclosures
Number of Loans | loan			215		197
Recorded Investment			$ 30,191,000		$ 29,874,000
Percentage of troubled debt restructurings performing as per terms of modifications	80.00%		80.00%		72.00%
Specific reserve allocations made to customers	$ 3,000,000		$ 3,000,000		$ 4,000,000
Percentage of Bank's TDRs that occurred during period, which were performing according to their modified terms	91.00%	26.00%	95.00%	32.00%
Specific reserve allocations made to customers whose loan terms were modified in TDRs during period	$ 155,000	$ 75,000	$ 186,000	$ 75,000
Performing Financing Receivable | Residential Real Estate
Troubled Debt Restructurings disclosures
Number of Loans | loan			197		174
Recorded Investment			$ 22,186,000		$ 19,702,000
Performing Financing Receivable | Residential Real Estate | Interest only payments
Troubled Debt Restructurings disclosures
Number of Loans | loan			1		2
Recorded Investment			$ 6,000		$ 155,000
Performing Financing Receivable | Residential Real Estate | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | loan			155		148
Recorded Investment			$ 19,103,000		$ 18,125,000
Performing Financing Receivable | Residential Real Estate | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan			18		7
Recorded Investment			$ 1,937,000		$ 616,000
Performing Financing Receivable | Residential Real Estate | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | loan			23		17
Recorded Investment			$ 1,140,000		$ 806,000
Performing Financing Receivable | Commercial Real Estate and Commercial Construction
Troubled Debt Restructurings disclosures
Number of Loans | loan			18		23
Recorded Investment			$ 8,005,000		$ 10,172,000
Performing Financing Receivable | Commercial Real Estate and Commercial Construction | Interest only payments
Troubled Debt Restructurings disclosures
Number of Loans | loan			3		5
Recorded Investment			$ 864,000		$ 2,666,000
Performing Financing Receivable | Commercial Real Estate and Commercial Construction | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | loan			7		8
Recorded Investment			$ 3,701,000		$ 4,769,000
Performing Financing Receivable | Commercial Real Estate and Commercial Construction | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan			8		10
Recorded Investment			$ 3,440,000		$ 2,737,000
Performing Financing Receivable | Modified During The Period
Troubled Debt Restructurings disclosures
Number of Loans | loan	14	5	17	11
Recorded Investment	$ 1,280,000	$ 613,000	$ 2,305,000	$ 932,000
Performing Financing Receivable | Modified During The Period | Residential Real Estate
Troubled Debt Restructurings disclosures
Number of Loans | loan	13	4	16	10
Recorded Investment	$ 1,038,000	$ 525,000	$ 2,063,000	$ 844,000
Performing Financing Receivable | Modified During The Period | Residential Real Estate | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | loan		1	1	5
Recorded Investment		$ 262,000	$ 220,000	$ 494,000
Performing Financing Receivable | Modified During The Period | Residential Real Estate | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan	7		9
Recorded Investment	$ 701,000		$ 1,506,000
Performing Financing Receivable | Modified During The Period | Residential Real Estate | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | loan	6	3	6	5
Recorded Investment	$ 337,000	$ 263,000	$ 337,000	$ 350,000
Performing Financing Receivable | Modified During The Period | Commercial Real Estate and Commercial Construction
Troubled Debt Restructurings disclosures
Number of Loans | loan	1	1	1	1
Recorded Investment	$ 242,000	$ 88,000	$ 242,000	$ 88,000
Performing Financing Receivable | Modified During The Period | Commercial Real Estate and Commercial Construction | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | loan		1		1
Recorded Investment		$ 88,000		$ 88,000
Performing Financing Receivable | Modified During The Period | Commercial Real Estate and Commercial Construction | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan	1		1
Recorded Investment	$ 242,000		$ 242,000
Nonperforming Financing Receivable
Troubled Debt Restructurings disclosures
Number of Loans | loan			72		111
Recorded Investment			$ 7,403,000		$ 11,712,000
Nonperforming Financing Receivable | Residential Real Estate
Troubled Debt Restructurings disclosures
Number of Loans | loan			65		103
Recorded Investment			$ 5,116,000		$ 9,051,000
Nonperforming Financing Receivable | Residential Real Estate | Interest only payments
Troubled Debt Restructurings disclosures
Number of Loans | loan			1		1
Recorded Investment			$ 467,000		$ 493,000
Nonperforming Financing Receivable | Residential Real Estate | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | loan			35		57
Recorded Investment			$ 3,271,000		$ 6,213,000
Nonperforming Financing Receivable | Residential Real Estate | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan			2		7
Recorded Investment			$ 123,000		$ 306,000
Nonperforming Financing Receivable | Residential Real Estate | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | loan			27		38
Recorded Investment			$ 1,255,000		$ 2,039,000
Nonperforming Financing Receivable | Commercial Real Estate and Commercial Construction
Troubled Debt Restructurings disclosures
Number of Loans | loan			7		8
Recorded Investment			$ 2,287,000		$ 2,661,000
Nonperforming Financing Receivable | Commercial Real Estate and Commercial Construction | Interest only payments
Troubled Debt Restructurings disclosures
Number of Loans | loan			1		1
Recorded Investment			$ 379,000		$ 413,000
Nonperforming Financing Receivable | Commercial Real Estate and Commercial Construction | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | loan			2		2
Recorded Investment			$ 210,000		$ 228,000
Nonperforming Financing Receivable | Commercial Real Estate and Commercial Construction | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan			4		5
Recorded Investment			$ 1,698,000		$ 2,020,000
Nonperforming Financing Receivable | Modified During The Period
Troubled Debt Restructurings disclosures
Number of Loans | loan	1	3	1	8
Recorded Investment	$ 131,000	$ 1,776,000	$ 131,000	$ 2,004,000
Nonperforming Financing Receivable | Modified During The Period | Residential Real Estate
Troubled Debt Restructurings disclosures
Number of Loans | loan	1	1	1	6
Recorded Investment	$ 131,000	$ 135,000	$ 131,000	$ 363,000
Nonperforming Financing Receivable | Modified During The Period | Residential Real Estate | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | loan				3
Recorded Investment				$ 151,000
Nonperforming Financing Receivable | Modified During The Period | Residential Real Estate | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | loan	1	1	1	3
Recorded Investment	$ 131,000	$ 135,000	$ 131,000	$ 212,000
Nonperforming Financing Receivable | Modified During The Period | Commercial Real Estate and Commercial Construction
Troubled Debt Restructurings disclosures
Number of Loans | loan		2		2
Recorded Investment		$ 1,641,000		$ 1,641,000
Nonperforming Financing Receivable | Modified During The Period | Commercial Real Estate and Commercial Construction | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | loan		1		1
Recorded Investment		$ 137,000		$ 137,000
Nonperforming Financing Receivable | Modified During The Period | Commercial Real Estate and Commercial Construction | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan		1		1
Recorded Investment		$ 1,504,000		$ 1,504,000