SEGMENTS INFORMATION (Reconciliation of Segment Operating Profit to Consolidated Income Before Provision for Income Taxes) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Segment operating profit	$ 96,396	$ 80,565	$ 267,331	$ 218,105
Stock-based compensation expense	23,474	15,471	54,794	53,024
Interest and other income, net	1,672	2,509	5,875	6,775
Foreign exchange gain/(loss)	5,896	(3,105)	3,253	(10,151)
Income before provision for income taxes	103,964	79,969	276,459	214,729
Operating Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Segment operating profit	133,248	112,384	356,006	311,893
Unallocated Amounts
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Stock-based compensation expense	(23,474)	(15,471)	(54,794)	(53,024)
Amortization of intangibles assets	(3,086)	(2,554)	(9,215)	(7,293)
Other acquisition-related expenses	(243)	(1,144)	(859)	(2,505)
Other unallocated expenses	$ (10,049)	$ (12,650)	$ (23,807)	$ (30,966)