| COMMITMENTS AND CONTINGENCIES - Schedule of Client Revenue Concentration (Details) | 3 Months Ended | |
|---|---|---|
| Mar. 31, 2018 | Mar. 31, 2017 | |
| Customer Concentration Risk | Revenue | North America | Client A | ||
| Product Information [Line Items] | ||
| Concentration Risk | 11.30% | 14.60% | 
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- Definition For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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