ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (INCOME STATEMENT CLASSIFICATION TABLE) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Presentation of Income Statement Reclassifications [Line Items]
Sales Revenue Services Net	$ 432,213	$ 394,356
Interest Expense.	9,592	5,288
Benefit from (provision for) income taxes	(10,199)	(7,466)
Net income	24,685	20,476
Accumulated Other Comprehensive Income (Loss)
Presentation of Income Statement Reclassifications [Line Items]
Net Income (Loss) - Other	21	1,894
Tax effect
Presentation of Income Statement Reclassifications [Line Items]
Provision for income taxes - Other	15	6
Derivative Valuation, Net of Tax
Presentation of Income Statement Reclassifications [Line Items]
Net Income (Loss) - Other	(110)	1,845
Reclassification from accumulated other comprehensive income
Presentation of Income Statement Reclassifications [Line Items]
Cost of services	(146)	(55)
Net Income (Loss) - Other	(131)	(49)
Reclassification from accumulated other comprehensive income | Foreign Currency Translation Adjustment
Presentation of Income Statement Reclassifications [Line Items]
Sales Revenue Services Net	151	(2,527)
Reclassification from accumulated other comprehensive income | Tax effect
Presentation of Income Statement Reclassifications [Line Items]
Benefit from (provision for) income taxes	(41)	682
Reclassification from accumulated other comprehensive income | Derivative Valuation, Net of Tax
Presentation of Income Statement Reclassifications [Line Items]
Net income	$ 110	$ (1,845)