SEGMENTS INFORMATION (Revenues by Customer Location) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ 652,243	$ 588,103	$ 1,935,985	$ 1,661,023
United States
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	371,366	340,803	1,106,459	959,471
United Kingdom
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	77,519	74,992	251,928	209,773
Switzerland
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	50,399	38,781	144,158	110,378
Netherlands
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	28,827	22,161	81,973	63,816
Russia
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	27,963	23,668	69,372	62,020
Germany
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	22,172	20,940	62,163	59,716
Canada
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	18,219	17,582	52,724	50,339
Other locations
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ 55,778	$ 49,176	$ 167,208	$ 145,510