Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock and Additional Paid-in Capital [Member]	Accumulated Other Comprehensive (Loss) Income [Member]	Retained Earnings [Member]
Beginning Balance (in shares) at Dec. 31, 2012		389,110,169
Beginning Balance at Dec. 31, 2012	$ 744,673	$ 301,672	$ 2,919	$ 440,082
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	112,403			112,403
Other comprehensive income (loss)	$ 656		656
Issuance of common stock upon exercise of options (in shares)	11,821,418	11,821,418
Issuance of common stock upon exercise of options	$ 124,557	$ 124,557
Note conversion (in shares)		16,317,420
Note conversion	198,208	$ 198,208
Stock-based compensation expense	73,100	73,100
Excess stock option income tax benefits	79,964	$ 79,964
Ending Balance (in shares) at Dec. 31, 2013		417,249,007
Ending Balance at Dec. 31, 2013	1,333,561	$ 777,501	3,575	552,485
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	266,799			266,799
Other comprehensive income (loss)	$ (8,021)		(8,021)
Issuance of common stock upon exercise of options (in shares)	5,661,880	5,661,880
Issuance of common stock upon exercise of options	$ 61,190	$ 61,190
Stock-based compensation expense	115,239	115,239
Excess stock option income tax benefits	88,940	$ 88,940
Ending Balance (in shares) at Dec. 31, 2014		422,910,887
Ending Balance at Dec. 31, 2014	1,857,708	$ 1,042,870	(4,446)	819,284
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	122,641			122,641
Other comprehensive income (loss)	$ (38,862)		(38,862)
Issuance of common stock upon exercise of options (in shares)	5,029,553	5,029,553
Issuance of common stock upon exercise of options	$ 77,334	$ 77,334
Stock-based compensation expense	124,725	124,725
Excess stock option income tax benefits	79,880	$ 79,880
Ending Balance (in shares) at Dec. 31, 2015		427,940,440
Ending Balance at Dec. 31, 2015	$ 2,223,426	$ 1,324,809	$ (43,308)	$ 941,925