DERIVATIVES (INCOME STATEMENT CLASSIFICATION) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Derivative Instruments, Gain (Loss) [Line Items]
Sales Revenue Services Net	$ 554,794	$ 453,081	$ 1,094,013	$ 885,294
Other nonoperating income expense	1,047	(1,761)	249	1,635
Designated as Hedging Instruments [Member] | Foreign Exchange [Member] | Cash Flow [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain or (loss) recognized in other comprehensive income (loss) - effective portion, net of tax:	1,354	58	2,413	168
Designated as Hedging Instruments [Member] | Foreign Exchange [Member] | Cash Flow [Member] | Reclassification from accumulated other comprehensive income | Revenue
Derivative Instruments, Gain (Loss) [Line Items]
Sales Revenue Services Net	1,830	79	3,260	230
Not Designated as Hedging Instruments [Member] | Foreign Exchange [Member] | Fair Value [Member] | Other income (expense), net
Derivative Instruments, Gain (Loss) [Line Items]
Other nonoperating income expense	$ 375	$ (14)	$ 38	$ (343)