DERIVATIVES (INCOME STATEMENT CLASSIFICATION) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Sales Revenue Services Net	$ 492,980	$ 395,507	$ 1,378,274	$ 1,182,378
Other nonoperating income expense	(18,663)	2,713	(17,028)	5,376
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:	515	(793)	683	(3,376)
Designated as Hedging Instruments [Member] | Foreign Exchange [Member] | Cash Flow [Member] | Reclassification from accumulated other comprehensive income
Derivative Instruments, Gain (Loss) [Line Items]
Sales Revenue Services Net	706	(1,087)	936	(4,625)
Not Designated as Hedging Instruments [Member] | Foreign Exchange [Member] | Fair Value [Member] | Reclassification from accumulated other comprehensive income
Derivative Instruments, Gain (Loss) [Line Items]
Other nonoperating income expense	$ 305	$ 57	$ (38)	$ (1,160)