EMPLOYEE BENEFIT PLANS - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jan. 13, 2017
Defined Benefit Plan Disclosure [Line Items]
Total 401(k) expense	$ 970,000	$ 439,000	$ 411,000
Split-dollar life insurance agreement
Defined Benefit Plan Disclosure [Line Items]
Accrued liability	687,000			$ 697,000
Certain prior executives and senior officers | Salary continuation agreement
Defined Benefit Plan Disclosure [Line Items]
Accrued liability	8,100,000			$ 7,700,000
Salary continuation agreement expense	581,000
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
After tax components of accumulated other comprehensive loss, not yet recognized in net periodic pension cost	208,000
Expected cash contributions	0
Expected amortization from accumulated other comprehensive loss into net periodic pension cost	$ 0
Pension Plans | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	48.00%
Pension Plans | Fixed-income securities
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	52.00%
Non-qualified Supplemental Executive Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
After tax components of accumulated other comprehensive loss, not yet recognized in net periodic pension cost	$ 348,000
Expected amortization from accumulated other comprehensive loss into net periodic pension cost	$ 29,000