Accumulated Other Comprehensive Loss - Schedule of Accumulated Other Comprehensive Income Loss (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance as of January 1, 2017			$ 3,224,370
Other comprehensive gain	$ 7,689	$ (1,846)	31,389	$ 7,991
Balance as of September 30, 2017	3,272,655		3,272,655
Foreign Currency Translation
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance as of January 1, 2017			(59,017)
Other comprehensive gain			29,951
Balance as of September 30, 2017	(29,066)		(29,066)
Net Unrealized Gains on Investments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance as of January 1, 2017			2,795
Other comprehensive gain			1,438
Balance as of September 30, 2017	4,233		4,233
Total
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance as of January 1, 2017			(56,222)
Other comprehensive gain			31,389
Balance as of September 30, 2017	$ (24,833)		$ (24,833)