CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Additional Paid-in Capital	Retained Earnings (Accumulated Deficit)	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Common Class A	Common Stock
Balance at Dec. 31, 2012	$ 1,256,618	$ 1,792,907	$ (535,220)	$ 0	$ (1,166)	$ 2	$ 95
Balance (shares) at Dec. 31, 2012				0		2,069	95,223
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Common Stock in connection with exercise of stock options	54,762	54,759					$ 3
Issuance of Common Stock in connection with exercise of stock options (shares)							3,052
Common Stock tendered upon exercise of stock options in connection with employee tax obligations	(195,087)	(195,086)					$ (1)
Common Stock tendered upon exercise of stock options in connection with employee tax obligations (in shares)							(701)
Issuance of Common Stock in connection with Company 401(k) Savings Plan contribution	5,718	5,718
Issuance of Common Stock in connection with Company 401(k) Savings Plan contribution (shares)							38
Issuance of restricted Common Stock under Long-Term Incentive Plan	0
Issuance of restricted Common Stock under Long-Term Incentive Plan (shares)							6
Conversion of Class A Stock to Common Stock (shares)						49	49
Stock-based compensation charges	217,080	217,080
Excess tax benefit from stock-based compensation	211,909	211,909
Net income	413,738
Other comprehensive income (loss), net of tax	(22)				(22)
Balance at Dec. 31, 2013	1,964,716	2,087,287	(121,482)	$ 0	(1,188)	$ 2	$ 97
Balance (shares) at Dec. 31, 2013				0		2,020	97,667
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Common Stock in connection with exercise of stock options	125,897	125,893					$ 4
Issuance of Common Stock in connection with exercise of stock options (shares)							3,468
Common Stock tendered upon exercise of stock options in connection with employee tax obligations	(267,584)	(267,583)					$ (1)
Common Stock tendered upon exercise of stock options in connection with employee tax obligations (in shares)							(754)
Issuance of Common Stock in connection with conversion of convertible senior notes	691,356	691,354					$ 2
Issuance of Common Stock in connection with conversion of convertible senior notes (in shares)							2,018
Issuance of Common Stock in connection with Company 401(k) Savings Plan contribution	13,125	13,125
Issuance of Common Stock in connection with Company 401(k) Savings Plan contribution (shares)							21
Issuance of restricted Common Stock under Long-Term Incentive Plan	0
Issuance of restricted Common Stock under Long-Term Incentive Plan (shares)							8
Conversion of Class A Stock to Common Stock (shares)						47	47
Stock-based compensation charges	326,815	326,815
Excess tax benefit from stock-based compensation	439,278	439,278
Acquisition of Common Stock in connection with exercise of convertible note hedges	0	169,530		$ 169,530
Acquisition of Common Stock in connection with exercise of convertible note hedges (in shares)				2,018
Reduction of warrants	(294,552)	(294,552)
Reclassification of warrant liability	(148,496)	(148,496)
Reduction of equity component of convertible senior notes	(691,869)	(691,869)
Net income	338,126
Other comprehensive income (loss), net of tax	53,439				53,439
Balance at Dec. 31, 2014	2,550,251	2,450,782	216,644	$ (169,530)	52,251	$ 2	$ 102
Balance (shares) at Dec. 31, 2014				2,018		1,973	102,475
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Common Stock in connection with exercise of stock options	215,462	215,460					$ 2
Issuance of Common Stock in connection with exercise of stock options (shares)							2,457
Common Stock tendered upon exercise of stock options in connection with employee tax obligations	(160,538)	(160,538)					$ 0
Common Stock tendered upon exercise of stock options in connection with employee tax obligations (in shares)							(298)
Issuance of Common Stock in connection with conversion of convertible senior notes	818,360	818,358					$ 2
Issuance of Common Stock in connection with conversion of convertible senior notes (in shares)							1,625
Issuance of Common Stock in connection with Company 401(k) Savings Plan contribution	15,382	15,382
Issuance of Common Stock in connection with Company 401(k) Savings Plan contribution (shares)							31
Issuance of restricted Common Stock under Long-Term Incentive Plan	0
Issuance of restricted Common Stock under Long-Term Incentive Plan (shares)							28
Conversion of Class A Stock to Common Stock (shares)						60	60
Stock-based compensation charges	464,022	464,022
Excess tax benefit from stock-based compensation	405,317	405,317
Acquisition of Common Stock in connection with exercise of convertible note hedges	0	136,539		$ 136,539
Acquisition of Common Stock in connection with exercise of convertible note hedges (in shares)				1,625
Reduction of warrants	(449,456)	(449,456)
Reclassification of warrant liability	(23,317)	(23,317)
Reduction of equity component of convertible senior notes	(819,657)	(819,657)
Net income	636,056
Other comprehensive income (loss), net of tax	(43,679)				(43,679)
Balance at Dec. 31, 2015	$ 3,654,837	$ 3,099,526	$ 852,700	$ (306,069)	$ 8,572	$ 2	$ 106
Balance (shares) at Dec. 31, 2015				3,643		1,913	106,378