GOODWILL (GOODWILL ROLLFORWARD) (Details) $ in Thousands	6 Months Ended
Jun. 30, 2018 USD ($)
Goodwill [Line Items]
Beginning balance, goodwill	$ 206,694
Acquisitions / Adjustments	1,097
Effect of Foreign Currency	(4,273)
Ending balance, goodwill	203,518
Customer Management Services [Member]
Goodwill [Line Items]
Beginning balance, goodwill	119,497
Acquisitions / Adjustments	(125)
Effect of Foreign Currency	(3,849)
Ending balance, goodwill	115,523
Customer Growth Services [Member]
Goodwill [Line Items]
Beginning balance, goodwill	24,439
Ending balance, goodwill	24,439
Customer Technology Services [Member]
Goodwill [Line Items]
Beginning balance, goodwill	40,839
Acquisitions / Adjustments	1,222
Effect of Foreign Currency	(49)
Ending balance, goodwill	42,012
Customer Strategy Services [Member]
Goodwill [Line Items]
Beginning balance, goodwill	21,919
Effect of Foreign Currency	(375)
Ending balance, goodwill	$ 21,544

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=77989000&loc=SL49117168-202975

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Amount of foreign currency translation gain (loss) which increases (decreases) an asset representing future economic benefits from other assets acquired in a business combination that are not individually identified and separately recognized.

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