LOANS AND ALLOWANCE FOR LOAN AND LEASE LOSSES - TDR ACCRUAL STATUS (Details) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2017 USD ($) loan	Dec. 31, 2016 USD ($) loan
Troubled Debt Restructurings disclosures
Number of Loans | loan	287	308
Recorded Investment | $	$ 37,594	$ 41,586
Residential Real Estate
Troubled Debt Restructurings disclosures
Number of Loans | loan	262	277
Recorded Investment | $	$ 27,302	$ 28,753
Commercial Real Estate
Troubled Debt Restructurings disclosures
Number of Loans | loan	19	23
Recorded Investment | $	$ 9,276	$ 11,265
Construction & land development
Troubled Debt Restructurings disclosures
Number of Loans | loan	4	5
Recorded Investment | $	$ 742	$ 881
Commercial & Industrial
Troubled Debt Restructurings disclosures
Number of Loans | loan	2	3
Recorded Investment | $	$ 274	$ 687
Loans on nonaccrual status
Troubled Debt Restructurings disclosures
Minimum period for which TDRs continue to be reported as non-performing loans	6 months
Number of Loans | loan	68	87
Recorded Investment | $	$ 7,205	$ 9,860
Loans on nonaccrual status | Residential Real Estate
Troubled Debt Restructurings disclosures
Number of Loans | loan	61	79
Recorded Investment | $	$ 4,918	$ 7,199
Loans on nonaccrual status | Commercial Real Estate
Troubled Debt Restructurings disclosures
Number of Loans | loan	6	6
Recorded Investment | $	$ 2,219	$ 2,430
Loans on nonaccrual status | Construction & land development
Troubled Debt Restructurings disclosures
Number of Loans | loan	1	1
Recorded Investment | $	$ 68	$ 77
Loans on nonaccrual status | Commercial & Industrial
Troubled Debt Restructurings disclosures
Number of Loans | loan		1
Recorded Investment | $		$ 154
Accrual Loans
Troubled Debt Restructurings disclosures
Number of Loans | loan	219	221
Recorded Investment | $	$ 30,389	$ 31,726
Accrual Loans | Residential Real Estate
Troubled Debt Restructurings disclosures
Number of Loans | loan	201	198
Recorded Investment | $	$ 22,384	$ 21,554
Accrual Loans | Commercial Real Estate
Troubled Debt Restructurings disclosures
Number of Loans | loan	13	17
Recorded Investment | $	$ 7,057	$ 8,835
Accrual Loans | Construction & land development
Troubled Debt Restructurings disclosures
Number of Loans | loan	3	4
Recorded Investment | $	$ 674	$ 804
Accrual Loans | Commercial & Industrial
Troubled Debt Restructurings disclosures
Number of Loans | loan	2	2
Recorded Investment | $	$ 274	$ 533