SEGMENTS INFORMATION (Revenues by Customer Location) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ 588,103	$ 468,186	$ 1,661,023	$ 1,337,981
United States
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	340,803	266,065	959,471	736,579
United Kingdom
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	74,992	50,482	209,773	152,315
Switzerland
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	38,781	35,524	110,378	105,396
Russia
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	23,668	15,609	62,020	51,930
Netherlands
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	22,161	17,031	63,816	51,934
Germany
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	20,940	20,732	59,716	60,331
Canada
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	17,582	18,008	50,339	51,391
Other
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ 49,176	$ 44,735	$ 145,510	$ 128,105