SEGMENT AND GEOGRAPHIC INFORMATION - Total Revenue by Major Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Segment Reporting Information [Line Items]
Revenues	$ 249,309	$ 212,673	$ 486,079	$ 415,207
United States
Segment Reporting Information [Line Items]
Revenues	191,872	162,511	373,101	315,270
Europe
Segment Reporting Information [Line Items]
Revenues	31,663	25,564	61,098	50,700
Rest of World
Segment Reporting Information [Line Items]
Revenues	$ 25,774	$ 24,598	$ 51,880	$ 49,237