ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (INCOME STATEMENT CLASSIFICATION TABLE) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Presentation of Income Statement Reclassifications [Line Items]
Revenues	$ 394,356	$ 375,249
Interest Expense.	5,288	6,459
Benefit from (provision for) income taxes	(7,466)	(2,102)
Net income	20,476	5,932
Accumulated Other Comprehensive Income (Loss)
Presentation of Income Statement Reclassifications [Line Items]
Net Income (Loss) - Other	1,894	3,994
Derivative Valuation, Net of Tax
Presentation of Income Statement Reclassifications [Line Items]
Net Income (Loss) - Other	1,845	3,893
Tax effect
Presentation of Income Statement Reclassifications [Line Items]
Provision for income taxes - Other	6	11
Reclassification from accumulated other comprehensive income
Presentation of Income Statement Reclassifications [Line Items]
Cost of services	(55)	(112)
Net Income (Loss) - Other	(49)	(101)
Reclassification from accumulated other comprehensive income | Foreign Currency Translation Adjustment
Presentation of Income Statement Reclassifications [Line Items]
Revenues	(2,527)	(5,332)
Reclassification from accumulated other comprehensive income | Derivative Valuation, Net of Tax
Presentation of Income Statement Reclassifications [Line Items]
Net income	(1,845)	(3,893)
Reclassification from accumulated other comprehensive income | Tax effect
Presentation of Income Statement Reclassifications [Line Items]
Benefit from (provision for) income taxes	$ 682	$ 1,439