LOANS AND ALLOWANCE FOR LOAN AND LEASE LOSSES - TDR MODIFICATIONS (Details)	3 Months Ended		12 Months Ended
	Mar. 31, 2017 USD ($) item	Mar. 31, 2016 USD ($) item	Dec. 31, 2016 USD ($) item
Troubled Debt Restructurings disclosures
Number of Loans | item	299		308
Recorded Investment	$ 38,762,000		$ 41,586,000
Commitments to lend any additional material amounts to existing TDR relationships	$ 0		$ 0
Residential Real Estate
Troubled Debt Restructurings disclosures
Number of Loans | item	270		277
Recorded Investment	$ 27,473,000		$ 28,753,000
Residential Real Estate | Interest only payments
Troubled Debt Restructurings disclosures
Number of Loans | item	3		3
Recorded Investment	$ 643,000		$ 648,000
Residential Real Estate | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | item	203		205
Recorded Investment	$ 23,885,000		$ 24,338,000
Residential Real Estate | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | item	13		14
Recorded Investment	$ 585,000		$ 922,000
Residential Real Estate | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | item	51		55
Recorded Investment	$ 2,360,000		$ 2,845,000
Commercial Real Estate and Commercial Construction
Troubled Debt Restructurings disclosures
Number of Loans | item	29		31
Recorded Investment	$ 11,289,000		$ 12,833,000
Commercial Real Estate and Commercial Construction | Interest only payments
Troubled Debt Restructurings disclosures
Number of Loans | item	6		6
Recorded Investment	$ 3,029,000		$ 3,079,000
Commercial Real Estate and Commercial Construction | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | item	9		10
Recorded Investment	$ 4,276,000		$ 4,997,000
Commercial Real Estate and Commercial Construction | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | item	14		15
Recorded Investment	$ 3,984,000		$ 4,757,000
Modified During The Period
Troubled Debt Restructurings disclosures
Number of Loans | item	3	8
Recorded Investment	$ 197,000	$ 713,000
Modified During The Period | Residential Real Estate
Troubled Debt Restructurings disclosures
Number of Loans | item	3	7
Recorded Investment	$ 197,000	$ 280,000
Modified During The Period | Residential Real Estate | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | item	1	3
Recorded Investment	$ 159,000	$ 112,000
Modified During The Period | Residential Real Estate | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | item	2	4
Recorded Investment	$ 38,000	$ 168,000
Modified During The Period | Commercial Real Estate and Commercial Construction
Troubled Debt Restructurings disclosures
Number of Loans | item		1
Recorded Investment		$ 433,000
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
Performing Financing Receivable
Troubled Debt Restructurings disclosures
Number of Loans | item	197		197
Recorded Investment	$ 28,011,000		$ 29,874,000
Percentage of troubled debt restructurings performing as per terms of modifications	72.00%		72.00%
Specific reserve allocations made to customers	$ 4,000,000		$ 4,000,000
Percentage of Bank's TDRs that occurred during period, which were performing according to their modified terms	100.00%	20.00%
Specific reserve allocations made to customers whose loan terms were modified in TDRs during period	$ 29,000	$ 17,000
Performing Financing Receivable | Residential Real Estate
Troubled Debt Restructurings disclosures
Number of Loans | item	176		174
Recorded Investment	$ 19,328,000		$ 19,702,000
Performing Financing Receivable | Residential Real Estate | Interest only payments
Troubled Debt Restructurings disclosures
Number of Loans | item	2		2
Recorded Investment	$ 158,000		$ 155,000
Performing Financing Receivable | Residential Real Estate | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | item	148		148
Recorded Investment	$ 17,961,000		$ 18,125,000
Performing Financing Receivable | Residential Real Estate | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | item	6		7
Recorded Investment	$ 314,000		$ 616,000
Performing Financing Receivable | Residential Real Estate | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | item	20		17
Recorded Investment	$ 895,000		$ 806,000
Performing Financing Receivable | Commercial Real Estate and Commercial Construction
Troubled Debt Restructurings disclosures
Number of Loans | item	21		23
Recorded Investment	$ 8,683,000		$ 10,172,000
Performing Financing Receivable | Commercial Real Estate and Commercial Construction | Interest only payments
Troubled Debt Restructurings disclosures
Number of Loans | item	5		5
Recorded Investment	$ 2,626,000		$ 2,666,000
Performing Financing Receivable | Commercial Real Estate and Commercial Construction | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | item	7		8
Recorded Investment	$ 4,051,000		$ 4,769,000
Performing Financing Receivable | Commercial Real Estate and Commercial Construction | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | item	9		10
Recorded Investment	$ 2,006,000		$ 2,737,000
Performing Financing Receivable | Modified During The Period
Troubled Debt Restructurings disclosures
Number of Loans | item	3	4
Recorded Investment	$ 197,000	$ 145,000
Performing Financing Receivable | Modified During The Period | Residential Real Estate
Troubled Debt Restructurings disclosures
Number of Loans | item	3	4
Recorded Investment	$ 197,000	$ 145,000
Performing Financing Receivable | Modified During The Period | Residential Real Estate | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | item	1	2
Recorded Investment	$ 159,000	$ 57,000
Performing Financing Receivable | Modified During The Period | Residential Real Estate | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | item	2	2
Recorded Investment	$ 38,000	$ 88,000
Nonperforming Financing Receivable
Troubled Debt Restructurings disclosures
Number of Loans | item	102		111
Recorded Investment	$ 10,751,000		$ 11,712,000
Nonperforming Financing Receivable | Residential Real Estate
Troubled Debt Restructurings disclosures
Number of Loans | item	94		103
Recorded Investment	$ 8,145,000		$ 9,051,000
Nonperforming Financing Receivable | Residential Real Estate | Interest only payments
Troubled Debt Restructurings disclosures
Number of Loans | item	1		1
Recorded Investment	$ 485,000		$ 493,000
Nonperforming Financing Receivable | Residential Real Estate | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | item	55		57
Recorded Investment	$ 5,924,000		$ 6,213,000
Nonperforming Financing Receivable | Residential Real Estate | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | item	7		7
Recorded Investment	$ 271,000		$ 306,000
Nonperforming Financing Receivable | Residential Real Estate | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | item	31		38
Recorded Investment	$ 1,465,000		$ 2,039,000
Nonperforming Financing Receivable | Commercial Real Estate and Commercial Construction
Troubled Debt Restructurings disclosures
Number of Loans | item	8		8
Recorded Investment	$ 2,606,000		$ 2,661,000
Nonperforming Financing Receivable | Commercial Real Estate and Commercial Construction | Interest only payments
Troubled Debt Restructurings disclosures
Number of Loans | item	1		1
Recorded Investment	$ 403,000		$ 413,000
Nonperforming Financing Receivable | Commercial Real Estate and Commercial Construction | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | item	2		2
Recorded Investment	$ 225,000		$ 228,000
Nonperforming Financing Receivable | Commercial Real Estate and Commercial Construction | Principal deferral
Troubled Debt Restructurings disclosures
Number of Loans | item	5		5
Recorded Investment	$ 1,978,000		$ 2,020,000
Nonperforming Financing Receivable | Modified During The Period
Troubled Debt Restructurings disclosures
Number of Loans | item		4
Recorded Investment		$ 568,000
Nonperforming Financing Receivable | Modified During The Period | Residential Real Estate
Troubled Debt Restructurings disclosures
Number of Loans | item		3
Recorded Investment		$ 135,000
Nonperforming Financing Receivable | Modified During The Period | Residential Real Estate | Rate reduction
Troubled Debt Restructurings disclosures
Number of Loans | item		1
Recorded Investment		$ 55,000
Nonperforming Financing Receivable | Modified During The Period | Residential Real Estate | Legal modifications
Troubled Debt Restructurings disclosures
Number of Loans | item		2
Recorded Investment		$ 80,000
Nonperforming Financing Receivable | Modified During The Period | Commercial Real Estate and Commercial Construction
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 | Interest only payments
Troubled Debt Restructurings disclosures
Number of Loans | item		1
Recorded Investment		$ 433,000