DERIVATIVES (INCOME STATEMENT CLASSIFICATION) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Derivative Instruments, Gain (Loss) [Line Items]
Sales Revenue Services Net	$ 566,734	$ 492,980	$ 1,660,747	$ 1,378,274
Other nonoperating income expense	3,288	(18,663)	3,537	(17,028)
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:	700	515	3,113	683
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	947	706	4,207	936
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	$ (80)	$ 305	$ (42)	$ (38)