Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	$ 3,191,860	$ 3,362,469	$ 3,270,218
Other comprehensive (loss) income	3,768	(26,982)	35,745
Ending Balance	3,657,958	3,191,860	3,362,469
Accumulated Other Comprehensive Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(48,912)	(21,930)	(57,675)
Ending Balance	(45,144)	(48,912)	$ (21,930)
Foreign Currency Translation
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(51,904)
Other comprehensive (loss) income	(1,020)
Ending Balance	(52,924)	(51,904)
Net Unrealized Gains on Investments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	2,992
Other comprehensive (loss) income	4,788
Ending Balance	$ 7,780	$ 2,992