LOANS AND ALLOWANCE FOR LOAN AND LEASE LOSSES - TDR MODIFICATIONS (Details)	3 Months Ended		12 Months Ended
	Mar. 31, 2016 USD ($) item	Mar. 31, 2015 USD ($) item	Dec. 31, 2015 USD ($) item
Troubled Debt Restructurings disclosures
Number of Loans | item	339		347
Recorded Investment	$ 46,167,000		$ 49,580,000
Commitments to lend any additional material amounts to existing TDR relationships	$ 0		$ 0
Residential Real Estate
Troubled Debt Restructurings disclosures
Number of Loans | item	303		307
Recorded Investment	$ 33,464,000		$ 35,209,000
Residential Real Estate | Interest only payments
Troubled Debt Restructurings disclosures
Number of Loans | item	2		2
Recorded Investment	$ 528,000		$ 631,000
Residential Real Estate | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | item	225		229
Recorded Investment	$ 28,780,000		$ 30,384,000
Residential Real Estate | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | item	17		16
Recorded Investment	$ 1,538,000		$ 1,560,000
Residential Real Estate | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | item	59		60
Recorded Investment	$ 2,618,000		$ 2,634,000
Commercial Real Estate and Commercial Construction
Troubled Debt Restructurings disclosures
Number of Loans | item	36		40
Recorded Investment	$ 12,703,000		$ 14,371,000
Commercial Real Estate and Commercial Construction | Interest only payments
Troubled Debt Restructurings disclosures
Number of Loans | item	6		7
Recorded Investment	$ 2,087,000		$ 1,998,000
Commercial Real Estate and Commercial Construction | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | item	13		13
Recorded Investment	$ 5,680,000		$ 5,748,000
Commercial Real Estate and Commercial Construction | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | item	17		20
Recorded Investment	$ 4,936,000		$ 6,625,000
Modified During The Period
Troubled Debt Restructurings disclosures
Number of Loans | item	8	15
Recorded Investment	$ 713,000	$ 3,608,000
Modified During The Period | Residential Real Estate
Troubled Debt Restructurings disclosures
Number of Loans | item	7	10
Recorded Investment	$ 280,000	$ 1,354,000
Modified During The Period | Residential Real Estate | Interest only payments
Troubled Debt Restructurings disclosures
Number of Loans | item		1
Recorded Investment		$ 621,000
Modified During The Period | Residential Real Estate | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | item	3	7
Recorded Investment	$ 112,000	$ 568,000
Modified During The Period | Residential Real Estate | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | item		1
Recorded Investment		$ 25,000
Modified During The Period | Residential Real Estate | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | item	4	1
Recorded Investment	$ 168,000	$ 140,000
Modified During The Period | Commercial Real Estate and Commercial Construction
Troubled Debt Restructurings disclosures
Number of Loans | item	1	5
Recorded Investment	$ 433,000	$ 2,254,000
Modified During The Period | Commercial Real Estate and Commercial Construction | Interest only payments
Troubled Debt Restructurings disclosures
Number of Loans | item	1	3
Recorded Investment	$ 433,000	$ 468,000
Modified During The Period | Commercial Real Estate and Commercial Construction | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | item		1
Recorded Investment		$ 1,730,000
Modified During The Period | Commercial Real Estate and Commercial Construction | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | item		1
Recorded Investment		$ 56,000
Performing Financing Receivable
Troubled Debt Restructurings disclosures
Number of Loans | item	247		252
Recorded Investment	$ 34,454,000		$ 36,644,000
Percentage of troubled debt restructurings performing as per terms of modifications	75.00%		74.00%
Specific reserve allocations made to customers	$ 5,000,000		$ 5,000,000
Percentage of Bank's TDRs that occurred during period, which were performing according to their modified terms	20.00%	41.00%
Specific reserve allocations made to customers whose loan terms were modified in TDRs during period	$ 17,000	$ 476,000
Performing Financing Receivable | Residential Real Estate
Troubled Debt Restructurings disclosures
Number of Loans | item	221		224
Recorded Investment	$ 25,633,000		$ 27,380,000
Performing Financing Receivable | Residential Real Estate | Interest only payments
Troubled Debt Restructurings disclosures
Number of Loans | item	1		2
Recorded Investment	$ 12,000		$ 631,000
Performing Financing Receivable | Residential Real Estate | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | item	180		183
Recorded Investment	$ 23,549,000		$ 24,734,000
Performing Financing Receivable | Residential Real Estate | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | item	10		9
Recorded Investment	$ 807,000		$ 789,000
Performing Financing Receivable | Residential Real Estate | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | item	30		30
Recorded Investment	$ 1,265,000		$ 1,226,000
Performing Financing Receivable | Commercial Real Estate and Commercial Construction
Troubled Debt Restructurings disclosures
Number of Loans | item	26		28
Recorded Investment	$ 8,821,000		$ 9,264,000
Performing Financing Receivable | Commercial Real Estate and Commercial Construction | Interest only payments
Troubled Debt Restructurings disclosures
Number of Loans | item	4		6
Recorded Investment	$ 1,193,000		$ 1,517,000
Performing Financing Receivable | Commercial Real Estate and Commercial Construction | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | item	10		10
Recorded Investment	$ 4,960,000		$ 5,021,000
Performing Financing Receivable | Commercial Real Estate and Commercial Construction | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | item	12		12
Recorded Investment	$ 2,668,000		$ 2,726,000
Performing Financing Receivable | Modified During The Period
Troubled Debt Restructurings disclosures
Number of Loans | item	4	8
Recorded Investment	$ 145,000	$ 1,497,000
Performing Financing Receivable | Modified During The Period | Residential Real Estate
Troubled Debt Restructurings disclosures
Number of Loans | item	4	5
Recorded Investment	$ 145,000	$ 1,029,000
Performing Financing Receivable | Modified During The Period | Residential Real Estate | Interest only payments
Troubled Debt Restructurings disclosures
Number of Loans | item		1
Recorded Investment		$ 621,000
Performing Financing Receivable | Modified During The Period | Residential Real Estate | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | item	2	4
Recorded Investment	$ 57,000	$ 408,000
Performing Financing Receivable | Modified During The Period | Residential Real Estate | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | item	2
Recorded Investment	$ 88,000
Performing Financing Receivable | Modified During The Period | Commercial Real Estate and Commercial Construction
Troubled Debt Restructurings disclosures
Number of Loans | item		3
Recorded Investment		$ 468,000
Performing Financing Receivable | Modified During The Period | Commercial Real Estate and Commercial Construction | Interest only payments
Troubled Debt Restructurings disclosures
Number of Loans | item		3
Recorded Investment		$ 468,000
Nonperforming Financing Receivable
Troubled Debt Restructurings disclosures
Number of Loans | item	92		95
Recorded Investment	$ 11,713,000		$ 12,936,000
Nonperforming Financing Receivable | Residential Real Estate
Troubled Debt Restructurings disclosures
Number of Loans | item	82		83
Recorded Investment	$ 7,831,000		$ 7,829,000
Nonperforming Financing Receivable | Residential Real Estate | Interest only payments
Troubled Debt Restructurings disclosures
Number of Loans | item	1
Recorded Investment	$ 516,000
Nonperforming Financing Receivable | Residential Real Estate | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | item	45		46
Recorded Investment	$ 5,231,000		$ 5,650,000
Nonperforming Financing Receivable | Residential Real Estate | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | item	7		7
Recorded Investment	$ 731,000		$ 771,000
Nonperforming Financing Receivable | Residential Real Estate | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | item	29		30
Recorded Investment	$ 1,353,000		$ 1,408,000
Nonperforming Financing Receivable | Commercial Real Estate and Commercial Construction
Troubled Debt Restructurings disclosures
Number of Loans | item	10		12
Recorded Investment	$ 3,882,000		$ 5,107,000
Nonperforming Financing Receivable | Commercial Real Estate and Commercial Construction | Interest only payments
Troubled Debt Restructurings disclosures
Number of Loans | item	2		1
Recorded Investment	$ 894,000		$ 481,000
Nonperforming Financing Receivable | Commercial Real Estate and Commercial Construction | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | item	3		3
Recorded Investment	$ 720,000		$ 727,000
Nonperforming Financing Receivable | Commercial Real Estate and Commercial Construction | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | item	5		8
Recorded Investment	$ 2,268,000		$ 3,899,000
Nonperforming Financing Receivable | Modified During The Period
Troubled Debt Restructurings disclosures
Number of Loans | item	4	7
Recorded Investment	$ 568,000	$ 2,111,000
Nonperforming Financing Receivable | Modified During The Period | Residential Real Estate
Troubled Debt Restructurings disclosures
Number of Loans | item	3	5
Recorded Investment	$ 135,000	$ 325,000
Nonperforming Financing Receivable | Modified During The Period | Residential Real Estate | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | item	1	3
Recorded Investment	$ 55,000	$ 160,000
Nonperforming Financing Receivable | Modified During The Period | Residential Real Estate | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | item		1
Recorded Investment		$ 25,000
Nonperforming Financing Receivable | Modified During The Period | Residential Real Estate | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | item	2	1
Recorded Investment	$ 80,000	$ 140,000
Nonperforming Financing Receivable | Modified During The Period | Commercial Real Estate and Commercial Construction
Troubled Debt Restructurings disclosures
Number of Loans | item	1	2
Recorded Investment	$ 433,000	$ 1,786,000
Nonperforming Financing Receivable | Modified During The Period | Commercial Real Estate and Commercial Construction | Interest only payments
Troubled Debt Restructurings disclosures
Number of Loans | item	1
Recorded Investment	$ 433,000
Nonperforming Financing Receivable | Modified During The Period | Commercial Real Estate and Commercial Construction | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | item		1
Recorded Investment		$ 1,730,000
Nonperforming Financing Receivable | Modified During The Period | Commercial Real Estate and Commercial Construction | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | item		1
Recorded Investment		$ 56,000