SEGMENTS INFORMATION (Revenues by Customer Location) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ 551,587	$ 445,647	$ 1,072,920	$ 869,795
United States
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	318,988	246,831	618,668	470,514
United Kingdom
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	69,042	50,103	134,781	101,833
Switzerland
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	35,364	34,268	71,597	69,872
Netherlands
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	21,039	17,254	41,655	34,903
Germany
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	19,622	20,111	38,776	39,599
Russia
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	22,460	16,909	38,352	36,321
Canada
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	15,785	17,620	32,757	33,383
Other
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ 49,287	$ 42,551	$ 96,334	$ 83,370