OPERATING SEGMENTS AND GEOGRAPHIC INFORMATION - Narrative (Details)	12 Months Ended
Dec. 31, 2018 USD ($) segment	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Segment Reporting [Abstract]
Number of reportable segments \| segment	2
Goodwill impairment \| $	$ 0	$ 0	$ 80,105,000

Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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