EMPLOYEE BENEFIT PLANS - Expense Relating to Various Employee Benefit Plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure
Employee benefit plans expense	$ 660	$ 393	$ 171
Pension plan
Defined Benefit Plan Disclosure
Employee benefit plans expense	(2)	(180)	(414)
401(k)
Defined Benefit Plan Disclosure
Employee benefit plans expense	$ 662	$ 573	$ 585