Accumulated Other Comprehensive Loss - Schedule of Accumulated Other Comprehensive Income Loss (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	$ 3,394,764	$ 3,445,278	$ 3,191,860	$ 3,362,469
Other comprehensive (loss) income	(13,940)	(6,247)	(7,512)	(26,288)
Ending Balance	3,501,600	3,155,531	3,501,600	3,155,531
Total
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	(42,484)	(41,971)	(48,912)	(21,930)
Ending Balance	(56,424)	$ (48,218)	(56,424)	$ (48,218)
Foreign Currency Translation
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance			(51,904)
Other comprehensive (loss) income			(10,744)
Ending Balance	(62,648)		(62,648)
Net Unrealized Gains on Investments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance			2,992
Other comprehensive (loss) income			3,232
Ending Balance	$ 6,224		$ 6,224