LOANS AND ALLOWANCE FOR LOAN AND LEASE LOSSES - TDR MODIFICATIONS (Details)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018 USD ($) loan	Sep. 30, 2017 USD ($) loan	Sep. 30, 2018 USD ($) loan	Sep. 30, 2017 USD ($) loan	Dec. 31, 2017 USD ($) loan
Troubled Debt Restructurings disclosures
Number of Loans | loan			533		1,097
Recorded Investment			$ 34,713,000		$ 34,637,000
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			227		245
Recorded Investment			$ 25,386,000		$ 25,115,000
Residential Real Estate | Interest only payments
Troubled Debt Restructurings disclosures
Number of Loans | loan			1		2
Recorded Investment			$ 1,200,000		$ 463,000
Residential Real Estate | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | loan			164		178
Recorded Investment			$ 18,782,000		$ 20,679,000
Residential Real Estate | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan			15		16
Recorded Investment			$ 3,429,000		$ 1,576,000
Residential Real Estate | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | loan			47		49
Recorded Investment			$ 1,975,000		$ 2,397,000
Commercial Real Estate and Commercial Construction
Troubled Debt Restructurings disclosures
Number of Loans | loan			24		22
Recorded Investment			$ 8,815,000		$ 8,885,000
Commercial Real Estate and Commercial Construction | Interest only payments
Troubled Debt Restructurings disclosures
Number of Loans | loan			2		3
Recorded Investment			$ 768,000		$ 837,000
Commercial Real Estate and Commercial Construction | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | loan			8		8
Recorded Investment			$ 3,076,000		$ 3,264,000
Commercial Real Estate and Commercial Construction | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan			14		11
Recorded Investment			$ 4,971,000		$ 4,784,000
Consumer and other
Troubled Debt Restructurings disclosures
Number of Loans | loan			282
Recorded Investment			$ 512,000
Consumer and other | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | loan			1
Recorded Investment			$ 16,000
Consumer and other | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan			279		830
Recorded Investment			$ 436,000		$ 637,000
Consumer and other | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | loan			2
Recorded Investment			$ 60,000
Consumer
Troubled Debt Restructurings disclosures
Number of Loans | loan			282		830
Recorded Investment			$ 512,000		$ 637,000
Modified During The Period
Troubled Debt Restructurings disclosures
Number of Loans | loan	5	15	24	18
Recorded Investment	$ 512,000	$ 1,411,000	$ 5,302,000	$ 2,436,000
Modified During The Period | Residential Real Estate
Troubled Debt Restructurings disclosures
Number of Loans | loan	1	14	16	17
Recorded Investment	$ 18,000	$ 1,169,000	$ 4,117,000	$ 2,194,000
Modified During The Period | Residential Real Estate | Interest only payments
Troubled Debt Restructurings disclosures
Number of Loans | loan			1
Recorded Investment			$ 1,200,000
Modified During The Period | Residential Real Estate | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | loan			2	1
Recorded Investment			$ 471,000	$ 220,000
Modified During The Period | Residential Real Estate | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan		7	4	9
Recorded Investment		$ 701,000	$ 2,166,000	$ 1,506,000
Modified During The Period | Residential Real Estate | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | loan	1	7	9	7
Recorded Investment	$ 18,000	$ 468,000	$ 280,000	$ 468,000
Modified During The Period | Commercial Real Estate and Commercial Construction
Troubled Debt Restructurings disclosures
Number of Loans | loan	2	1	5	1
Recorded Investment	$ 434,000	$ 242,000	$ 1,071,000	$ 242,000
Modified During The Period | Commercial Real Estate and Commercial Construction | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan	2	1	5	1
Recorded Investment	$ 434,000	$ 242,000	$ 1,071,000	$ 242,000
Modified During The Period | Consumer
Troubled Debt Restructurings disclosures
Number of Loans | loan	2		3
Recorded Investment	$ 60,000		$ 114,000
Modified During The Period | Consumer | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan	2		1
Recorded Investment	$ 60,000		$ 54,000
Modified During The Period | Consumer | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | loan			2
Recorded Investment			$ 60,000
Performing Financing Receivable
Troubled Debt Restructurings disclosures
Number of Loans | loan			500		1,068
Recorded Investment			$ 28,760,000		$ 30,781,000
Percentage of troubled debt restructurings performing as per terms of modifications	83.00%		83.00%		89.00%
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	85.00%	91.00%	30.00%	95.00%
Specific reserve allocations made to customers whose loan terms were modified in TDRs during period	$ 78,000	$ 155,000	$ 577,000	$ 186,000
Performing Financing Receivable | Residential Real Estate
Troubled Debt Restructurings disclosures
Number of Loans | loan			196		219
Recorded Investment			$ 19,493,000		$ 22,692,000
Performing Financing Receivable | Residential Real Estate | Interest only payments
Troubled Debt Restructurings disclosures
Number of Loans | loan					2
Recorded Investment					$ 463,000
Performing Financing Receivable | Residential Real Estate | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | loan			148		161
Recorded Investment			$ 16,594,000		$ 18,777,000
Performing Financing Receivable | Residential Real Estate | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan			10		14
Recorded Investment			$ 1,248,000		$ 1,455,000
Performing Financing Receivable | Residential Real Estate | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | loan			38		42
Recorded Investment			$ 1,651,000		$ 1,997,000
Performing Financing Receivable | Commercial Real Estate and Commercial Construction
Troubled Debt Restructurings disclosures
Number of Loans | loan			24		19
Recorded Investment			$ 8,815,000		$ 7,452,000
Performing Financing Receivable | Commercial Real Estate and Commercial Construction | Interest only payments
Troubled Debt Restructurings disclosures
Number of Loans | loan			2		3
Recorded Investment			$ 768,000		$ 837,000
Performing Financing Receivable | Commercial Real Estate and Commercial Construction | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | loan			8		7
Recorded Investment			$ 3,076,000		$ 3,185,000
Performing Financing Receivable | Commercial Real Estate and Commercial Construction | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan			14		9
Recorded Investment			$ 4,971,000		$ 3,430,000
Performing Financing Receivable | Consumer and other
Troubled Debt Restructurings disclosures
Number of Loans | loan			280
Recorded Investment			$ 452,000
Performing Financing Receivable | Consumer and other | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | loan			1
Recorded Investment			$ 16,000
Performing Financing Receivable | Consumer and other | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan			279		830
Recorded Investment			$ 436,000		$ 637,000
Performing Financing Receivable | Modified During The Period
Troubled Debt Restructurings disclosures
Number of Loans | loan	2	14	14	17
Recorded Investment	$ 433,000	$ 1,280,000	$ 1,616,000	$ 2,305,000
Performing Financing Receivable | Modified During The Period | Residential Real Estate
Troubled Debt Restructurings disclosures
Number of Loans | loan		13	8	16
Recorded Investment		$ 1,038,000	$ 491,000	$ 2,063,000
Performing Financing Receivable | Modified During The Period | Residential Real Estate | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | loan			1	1
Recorded Investment			$ 386,000	$ 220,000
Performing Financing Receivable | Modified During The Period | Residential Real Estate | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan		7	1	9
Recorded Investment		$ 701,000	$ 15,000	$ 1,506,000
Performing Financing Receivable | Modified During The Period | Residential Real Estate | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | loan		6	6	6
Recorded Investment		$ 337,000	$ 90,000	$ 337,000
Performing Financing Receivable | Modified During The Period | Commercial Real Estate and Commercial Construction
Troubled Debt Restructurings disclosures
Number of Loans | loan	2	1	5	1
Recorded Investment	$ 433,000	$ 242,000	$ 1,071,000	$ 242,000
Performing Financing Receivable | Modified During The Period | Commercial Real Estate and Commercial Construction | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan	2	1	5	1
Recorded Investment	$ 433,000	$ 242,000	$ 1,071,000	$ 242,000
Performing Financing Receivable | Modified During The Period | Consumer
Troubled Debt Restructurings disclosures
Number of Loans | loan			1
Recorded Investment			$ 54,000
Performing Financing Receivable | Modified During The Period | Consumer | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan			1
Recorded Investment			$ 54,000
Nonperforming Financing Receivable
Troubled Debt Restructurings disclosures
Number of Loans | loan			33		29
Recorded Investment			$ 5,953,000		$ 3,856,000
Nonperforming Financing Receivable | Residential Real Estate
Troubled Debt Restructurings disclosures
Number of Loans | loan			31		26
Recorded Investment			$ 5,893,000		$ 2,423,000
Nonperforming Financing Receivable | Residential Real Estate | Interest only payments
Troubled Debt Restructurings disclosures
Number of Loans | loan			1
Recorded Investment			$ 1,200,000
Nonperforming Financing Receivable | Residential Real Estate | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | loan			16		17
Recorded Investment			$ 2,188,000		$ 1,902,000
Nonperforming Financing Receivable | Residential Real Estate | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan			5		2
Recorded Investment			$ 2,181,000		$ 121,000
Nonperforming Financing Receivable | Residential Real Estate | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | loan			9		7
Recorded Investment			$ 324,000		$ 400,000
Nonperforming Financing Receivable | Commercial Real Estate and Commercial Construction
Troubled Debt Restructurings disclosures
Number of Loans | loan					3
Recorded Investment					$ 1,433,000
Nonperforming Financing Receivable | Commercial Real Estate and Commercial Construction | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | loan					1
Recorded Investment					$ 79,000
Nonperforming Financing Receivable | Commercial Real Estate and Commercial Construction | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan					2
Recorded Investment					$ 1,354,000
Nonperforming Financing Receivable | Consumer and other
Troubled Debt Restructurings disclosures
Number of Loans | loan			2
Recorded Investment			$ 60,000
Nonperforming Financing Receivable | Consumer and other | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | loan			2
Recorded Investment			$ 60,000
Nonperforming Financing Receivable | Modified During The Period
Troubled Debt Restructurings disclosures
Number of Loans | loan	3	1	10	1
Recorded Investment	$ 79,000	$ 131,000	$ 3,686,000	$ 131,000
Nonperforming Financing Receivable | Modified During The Period | Residential Real Estate
Troubled Debt Restructurings disclosures
Number of Loans | loan	1	1	8	1
Recorded Investment	$ 18,000	$ 131,000	$ 3,626,000	$ 131,000
Nonperforming Financing Receivable | Modified During The Period | Residential Real Estate | Interest only payments
Troubled Debt Restructurings disclosures
Number of Loans | loan			1
Recorded Investment			$ 1,200,000
Nonperforming Financing Receivable | Modified During The Period | Residential Real Estate | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | loan			1
Recorded Investment			$ 85,000
Nonperforming Financing Receivable | Modified During The Period | Residential Real Estate | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan			3
Recorded Investment			$ 2,151,000
Nonperforming Financing Receivable | Modified During The Period | Residential Real Estate | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | loan	1	1	3	1
Recorded Investment	$ 18,000	$ 131,000	$ 190,000	$ 131,000
Nonperforming Financing Receivable | Modified During The Period | Commercial Real Estate and Commercial Construction
Troubled Debt Restructurings disclosures
Recorded Investment	1,000
Nonperforming Financing Receivable | Modified During The Period | Commercial Real Estate and Commercial Construction | Principal deferral
Troubled Debt Restructurings disclosures
Recorded Investment	$ 1,000
Nonperforming Financing Receivable | Modified During The Period | Consumer
Troubled Debt Restructurings disclosures
Number of Loans | loan	2		2
Recorded Investment	$ 60,000		$ 60,000
Nonperforming Financing Receivable | Modified During The Period | Consumer | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan	2
Recorded Investment	$ 60,000
Nonperforming Financing Receivable | Modified During The Period | Consumer | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | loan			2
Recorded Investment			$ 60,000