NATURE OF BUSINESS (Details)	Dec. 31, 2018 country
Minimum
Nature of business
Number of countries in which company delivers comprehensive programs and services	170

The number of countries in which the entity operates as of balance sheet date.

No definition available.

Name:	us-gaap_NumberOfCountriesInWhichEntityOperates
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant