SEGMENT AND GEOGRAPHIC INFORMATION (Total Revenue by Major Geographic Area) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Total revenue, net	$ 383,315	$ 365,854	$ 366,190	$ 357,082	$ 368,602	$ 278,834	$ 282,164	$ 258,636	$ 1,472,441	$ 1,188,236	$ 992,075
Total long-lived assets	320,029				285,329				320,029	285,329
United States (Includes long-lived assets in Puerto Rico)
Segment Reporting Information [Line Items]
Total revenue, net									1,045,887	894,260	765,608
Total long-lived assets	280,382				247,154				280,382	247,154
Europe
Segment Reporting Information [Line Items]
Total revenue, net									201,354	150,147	120,588
Total long-lived assets	32,679				30,942				32,679	30,942
Asia Pacific
Segment Reporting Information [Line Items]
Total revenue, net									144,253	80,636	59,985
Total long-lived assets	3,765				4,189				3,765	4,189
Rest of the World
Segment Reporting Information [Line Items]
Total revenue, net									80,947	63,193	$ 45,894
Total long-lived assets	$ 3,203				$ 3,044				$ 3,203	$ 3,044