LOANS AND ALLOWANCE FOR LOAN AND LEASE LOSSES - TDR MODIFICATIONS (Details)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019 USD ($) loan	Sep. 30, 2018 USD ($) loan	Sep. 30, 2019 USD ($) loan	Sep. 30, 2018 USD ($) loan	Dec. 31, 2018 USD ($) loan
Troubled Debt Restructurings disclosures
Number of Loans | loan			597		495
Recorded Investment			$ 30,161,000		$ 32,863,000
Commitments to lend any additional material amounts to existing TDR relationships	$ 0		$ 0		$ 0
Residential Real Estate
Troubled Debt Restructurings disclosures
Number of Loans | loan			203		216
Recorded Investment			$ 20,823,000		$ 23,610,000
Residential Real Estate | Interest only payments
Troubled Debt Restructurings disclosures
Number of Loans | loan			1		1
Recorded Investment			$ 925,000		$ 970,000
Residential Real Estate | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | loan			127		157
Recorded Investment			$ 14,774,000		$ 17,870,000
Residential Real Estate | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan			11		15
Recorded Investment			$ 1,039,000		$ 3,042,000
Residential Real Estate | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | loan			64		43
Recorded Investment			$ 4,085,000		$ 1,728,000
Commercial Real Estate and Commercial Construction
Troubled Debt Restructurings disclosures
Number of Loans | loan			19		23
Recorded Investment			$ 8,935,000		$ 8,818,000
Commercial Real Estate and Commercial Construction | Interest only payments
Troubled Debt Restructurings disclosures
Number of Loans | loan			2		2
Recorded Investment			$ 702,000		$ 752,000
Commercial Real Estate and Commercial Construction | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | loan			4		8
Recorded Investment			$ 1,300,000		$ 2,962,000
Commercial Real Estate and Commercial Construction | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan			11		12
Recorded Investment			$ 4,361,000		$ 5,076,000
Commercial Real Estate and Commercial Construction | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | loan			2		1
Recorded Investment			$ 2,572,000		$ 28,000
Consumer and other
Troubled Debt Restructurings disclosures
Number of Loans | loan			375		256
Recorded Investment			$ 403,000		$ 435,000
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			373		255
Recorded Investment			$ 390,000		$ 419,000
Consumer
Troubled Debt Restructurings disclosures
Number of Loans | loan			375		256
Recorded Investment			$ 403,000		$ 435,000
Consumer loans | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | loan			2
Recorded Investment			$ 13,000
Modified During The Period
Troubled Debt Restructurings disclosures
Number of Loans | loan	11	5	42	24
Recorded Investment	$ 1,004,000	$ 512,000	$ 6,293,000	$ 5,302,000
Modified During The Period | Residential Real Estate
Troubled Debt Restructurings disclosures
Number of Loans | loan	9	1	35	16
Recorded Investment	$ 992,000	$ 18,000	$ 3,131,000	$ 4,117,000
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			1	2
Recorded Investment			$ 371,000	$ 471,000
Modified During The Period | Residential Real Estate | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan			1	4
Recorded Investment			$ 4,000	$ 2,166,000
Modified During The Period | Residential Real Estate | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | loan	9	1	33	9
Recorded Investment	$ 992,000	$ 18,000	$ 2,756,000	$ 280,000
Modified During The Period | Commercial Real Estate and Commercial Construction
Troubled Debt Restructurings disclosures
Number of Loans | loan		2	5	5
Recorded Investment		$ 434,000	$ 3,150,000	$ 1,071,000
Modified During The Period | Commercial Real Estate and Commercial Construction | Interest only payments
Troubled Debt Restructurings disclosures
Number of Loans | loan			1
Recorded Investment			$ 553,000
Modified During The Period | Commercial Real Estate and Commercial Construction | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan		2	2	5
Recorded Investment		$ 434,000	$ 25,000	$ 1,071,000
Modified During The Period | Commercial Real Estate and Commercial Construction | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | loan			2
Recorded Investment			$ 2,572,000
Modified During The Period | Consumer loans
Troubled Debt Restructurings disclosures
Number of Loans | loan	2	2	2	3
Recorded Investment	$ 12,000	$ 60,000	$ 12,000	$ 114,000
Modified During The Period | Consumer loans | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan				1
Recorded Investment				$ 54,000
Modified During The Period | Consumer loans | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | loan	2	2	2	2
Recorded Investment	$ 12,000	$ 60,000	$ 12,000	$ 60,000
Performing Financing Receivable
Troubled Debt Restructurings disclosures
Number of Loans | loan			556		469
Recorded Investment			$ 23,773,000		$ 28,788,000
Percentage of troubled debt restructurings performing as per terms of modifications	79.00%		79.00%		88.00%
Specific reserve allocations made to customers	$ 3,000,000		$ 3,000,000		$ 3,000,000
Percentage of Bank's TDRs that occurred during period, which were performing according to their modified terms	68.00%	85.00%	24.00%	30.00%
Specific reserve allocations made to customers whose loan terms were modified in TDRs during period	$ 980,000	$ 422,000	$ 1,500,000	$ 577,000
Performing Financing Receivable | Residential Real Estate
Troubled Debt Restructurings disclosures
Number of Loans | loan			169		191
Recorded Investment			$ 17,843,000		$ 19,563,000
Performing Financing Receivable | Residential Real Estate | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | loan			113		145
Recorded Investment			$ 13,833,000		$ 16,892,000
Performing Financing Receivable | Residential Real Estate | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan			9		11
Recorded Investment			$ 860,000		$ 1,171,000
Performing Financing Receivable | Residential Real Estate | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | loan			47		35
Recorded Investment			$ 3,150,000		$ 1,500,000
Performing Financing Receivable | Commercial Real Estate and Commercial Construction
Troubled Debt Restructurings disclosures
Number of Loans | loan			13		22
Recorded Investment			$ 5,530,000		$ 8,790,000
Performing Financing Receivable | Commercial Real Estate and Commercial Construction | Interest only payments
Troubled Debt Restructurings disclosures
Number of Loans | loan			2		2
Recorded Investment			$ 702,000		$ 752,000
Performing Financing Receivable | Commercial Real Estate and Commercial Construction | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | loan			2		8
Recorded Investment			$ 1,197,000		$ 2,962,000
Performing Financing Receivable | Commercial Real Estate and Commercial Construction | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan			9		12
Recorded Investment			$ 3,631,000		$ 5,076,000
Performing Financing Receivable | Consumer and other
Troubled Debt Restructurings disclosures
Number of Loans | loan			374		256
Recorded Investment			$ 400,000		$ 435,000
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			373		255
Recorded Investment			$ 390,000		$ 419,000
Performing Financing Receivable | Consumer loans | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | loan			1
Recorded Investment			$ 10,000
Performing Financing Receivable | Modified During The Period
Troubled Debt Restructurings disclosures
Number of Loans | loan	6	2	30	14
Recorded Investment	$ 687,000	$ 433,000	$ 3,018,000	$ 1,616,000
Performing Financing Receivable | Modified During The Period | Residential Real Estate
Troubled Debt Restructurings disclosures
Number of Loans | loan	5		26	8
Recorded Investment	$ 677,000		$ 2,430,000	$ 491,000
Performing Financing Receivable | Modified During The Period | Residential Real Estate | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | loan			1	1
Recorded Investment			$ 371,000	$ 386,000
Performing Financing Receivable | Modified During The Period | Residential Real Estate | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan			1	1
Recorded Investment			$ 4,000	$ 15,000
Performing Financing Receivable | Modified During The Period | Residential Real Estate | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | loan	5		24	6
Recorded Investment	$ 677,000		$ 2,055,000	$ 90,000
Performing Financing Receivable | Modified During The Period | Commercial Real Estate and Commercial Construction
Troubled Debt Restructurings disclosures
Number of Loans | loan		2	3	5
Recorded Investment		$ 433,000	$ 578,000	$ 1,071,000
Performing Financing Receivable | Modified During The Period | Commercial Real Estate and Commercial Construction | Interest only payments
Troubled Debt Restructurings disclosures
Number of Loans | loan			1
Recorded Investment			$ 553,000
Performing Financing Receivable | Modified During The Period | Commercial Real Estate and Commercial Construction | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan		2	2	5
Recorded Investment		$ 433,000	$ 25,000	$ 1,071,000
Performing Financing Receivable | Modified During The Period | Consumer loans
Troubled Debt Restructurings disclosures
Number of Loans | loan	1		1	1
Recorded Investment	$ 10,000		$ 10,000	$ 54,000
Performing Financing Receivable | Modified During The Period | Consumer loans | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan				1
Recorded Investment				$ 54,000
Performing Financing Receivable | Modified During The Period | Consumer loans | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | loan	1		1
Recorded Investment	$ 10,000		$ 10,000
Nonperforming Financing Receivable
Troubled Debt Restructurings disclosures
Number of Loans | loan			41		26
Recorded Investment			$ 6,388,000		$ 4,075,000
Nonperforming Financing Receivable | Residential Real Estate
Troubled Debt Restructurings disclosures
Number of Loans | loan			34		25
Recorded Investment			$ 2,980,000		$ 4,047,000
Nonperforming Financing Receivable | Residential Real Estate | Interest only payments
Troubled Debt Restructurings disclosures
Number of Loans | loan			1		1
Recorded Investment			$ 925,000		$ 970,000
Nonperforming Financing Receivable | Residential Real Estate | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | loan			14		12
Recorded Investment			$ 941,000		$ 978,000
Nonperforming Financing Receivable | Residential Real Estate | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan			2		4
Recorded Investment			$ 179,000		$ 1,871,000
Nonperforming Financing Receivable | Residential Real Estate | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | loan			17		8
Recorded Investment			$ 935,000		$ 228,000
Nonperforming Financing Receivable | Commercial Real Estate and Commercial Construction
Troubled Debt Restructurings disclosures
Number of Loans | loan			6		1
Recorded Investment			$ 3,405,000		$ 28,000
Nonperforming Financing Receivable | Commercial Real Estate and Commercial Construction | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | loan			2
Recorded Investment			$ 103,000
Nonperforming Financing Receivable | Commercial Real Estate and Commercial Construction | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | loan			2
Recorded Investment			$ 730,000
Nonperforming Financing Receivable | Commercial Real Estate and Commercial Construction | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | loan			2		1
Recorded Investment			$ 2,572,000		$ 28,000
Nonperforming Financing Receivable | Consumer and other
Troubled Debt Restructurings disclosures
Number of Loans | loan			1
Recorded Investment			$ 3,000
Nonperforming Financing Receivable | Consumer loans | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | loan			1
Recorded Investment			$ 3,000
Nonperforming Financing Receivable | Modified During The Period
Troubled Debt Restructurings disclosures
Number of Loans | loan	5	3	12	10
Recorded Investment	$ 317,000	$ 79,000	$ 3,275,000	$ 3,686,000
Nonperforming Financing Receivable | Modified During The Period | Residential Real Estate
Troubled Debt Restructurings disclosures
Number of Loans | loan	4	1	9	8
Recorded Investment	$ 315,000	$ 18,000	$ 701,000	$ 3,626,000
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	4	1	9	3
Recorded Investment	$ 315,000	$ 18,000	$ 701,000	$ 190,000
Nonperforming Financing Receivable | Modified During The Period | Commercial Real Estate and Commercial Construction
Troubled Debt Restructurings disclosures
Number of Loans | loan			2
Recorded Investment		1,000	$ 2,572,000
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 | Commercial Real Estate and Commercial Construction | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | loan			2
Recorded Investment			$ 2,572,000
Nonperforming Financing Receivable | Modified During The Period | Consumer loans
Troubled Debt Restructurings disclosures
Number of Loans | loan	1	2	1	2
Recorded Investment	$ 2,000	$ 60,000	$ 2,000	$ 60,000
Nonperforming Financing Receivable | Modified During The Period | Consumer loans | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | loan	1	2	1	2
Recorded Investment	$ 2,000	$ 60,000	$ 2,000	$ 60,000