ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (INCOME STATEMENT CLASSIFICATION TABLE) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Presentation of Income Statement Reclassifications [Line Items]
Sales Revenue Services Net	$ 554,794	$ 453,081	$ 1,094,013	$ 885,294
Benefit from (provision for) income taxes	(11,353)	(11,039)	(27,332)	(21,238)
Net income	52,373	33,549	107,397	58,234
Provision for income taxes - Other			16	30
Accumulated Other Comprehensive Income (Loss)
Presentation of Income Statement Reclassifications [Line Items]
Net Income (Loss) - Other			(2,269)	96
Derivative Valuation, Net of Tax
Presentation of Income Statement Reclassifications [Line Items]
Net income			2,413	168
Net Income (Loss) - Other			(2,413)	(168)
Cost of Services
Presentation of Income Statement Reclassifications [Line Items]
Cost of services			(160)	(294)
Reclassification from accumulated other comprehensive income
Presentation of Income Statement Reclassifications [Line Items]
Cost of services	(80)	(147)
Net Income (Loss) - Other	(72)	(132)	(144)	(264)
Reclassification from accumulated other comprehensive income | Tax effect
Presentation of Income Statement Reclassifications [Line Items]
Benefit from (provision for) income taxes	(476)	(21)	(847)	(62)
Provision for income taxes - Other	8	15
Reclassification from accumulated other comprehensive income | Derivative Valuation, Net of Tax
Presentation of Income Statement Reclassifications [Line Items]
Net income	1,354	58
Foreign Exchange Forward | Reclassification from accumulated other comprehensive income | Foreign Currency Translation Adjustment
Presentation of Income Statement Reclassifications [Line Items]
Sales Revenue Services Net	$ 1,830	$ 79	$ 3,260	$ 230