EMPLOYEE BENEFIT PLANS (Details) - USD ($) $ in Thousands	6 Months Ended
Jun. 30, 2019	Dec. 31, 2018
Retirement Benefits [Abstract]
Accrued severance liabilities	$ 6,778	$ 21,645
Severance assets	5,428	17,043
Unfunded portion	$ 1,350	$ 4,602
Company's contribution as a percentage of employee monthly salary	8.30%

Liability for amount due employees, in addition to wages and any other money that employers owe employees, when their employment ends through a layoff or other termination. For example, a company may provide involuntarily terminated employees with a lump sum payment equal to one week's salary for every year of employment.

No definition available.

Name:	us-gaap_SupplementalUnemploymentBenefitsSeveranceBenefits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant