PROPERTY AND EQUIPMENT (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 535,132	$ 442,947
Less: accumulated depreciation and amortization	(260,346)	(243,994)
Property and equipment, net	274,786	198,953
Depreciation	101,517	78,241	$ 48,365
Retirement of Property and Equipment	75,000
Computer equipment and software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 396,961	332,650
Computer equipment and software | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives (years)	2 years
Computer equipment and software | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives (years)	5 years
Office equipment, furniture, fixtures & leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 138,171	$ 110,297
Office equipment, furniture, fixtures & leasehold improvements | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives (years)	2 years
Office equipment, furniture, fixtures & leasehold improvements | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives (years)	11 years