EMPLOYEE BENEFITS (Employee benefits) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Retirement Benefits [Abstract]
Discretionary matching contribution to retirement plan by employer (as a percent)	2.00%
Vesting period	2 years
Employer contributions charged to expenses	$ 2,331	$ 1,934	$ 740