DERIVATIVES - Schedule of the activity of the foreign currency contracts (Details) - Cash Flow Hedging - Designated as Hedging Instrument - Foreign currency contracts - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Derivative [Line Items]
Tax on unrealized losses arising from foreign currency contracts	$ 100	$ 100	$ 100	$ 100
Unrealized gain, net of less than $0.1 million and $0.1 million income tax, respectively, included in “Accumulated items of other comprehensive loss” in the accompanying consolidated balance sheets	0	75	145	713
Realized loss on effective portion, included as compensation expense in “Direct costs of customer support” and “Sales, general and administrative” in the accompanying consolidated statements of operations and comprehensive loss	$ 0	$ (20)	$ (171)	$ (199)