IMPAIRED LOANS AND ALLOWANCE FOR LOAN LOSSES - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring Outstanding	$ 16,200,000		$ 16,200,000		$ 17,700,000
Loans and Leases Receivable, Impaired, Interest Income Recognized, Change in Present Value Attributable to Passage of Time	169,000	$ 83,000	282,000	$ 176,000
Nonaccrual loans and loans past due ninety days	14,375,000		14,375,000		18,071,000
Purchased Loans [Member]
Financing Receivable, Modifications [Line Items]
Nonaccrual loans and loans past due ninety days	3,500,000		3,500,000		7,000,000
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0		0		0
Nonaccrual [Member]
Financing Receivable, Modifications [Line Items]
Nonaccrual loans and loans past due ninety days	10,900,000		10,900,000		11,000,000
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	$ 0		0		0
Loans [Member] | Bank shares, Inc [Member]
Financing Receivable, Modifications [Line Items]
Assets, Fair Value Adjustment			$ 15,600,000		$ 13,700,000
Fair value adjustment Percent	2.77%		2.77%		3.11%