Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	$ 1,708,625	$ 1,634,501	$ 1,738,778	$ 1,593,147
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Other comprehensive loss before reclassifications			(4,349)
Amounts reclassified from accumulated other comprehensive loss			455
Total other comprehensive income (loss), net of tax	6,781	(5,040)	(3,894)	(2,780)
Ending balance	1,729,433	1,703,307	1,729,433	1,703,307
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance			(23,969)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Other comprehensive loss before reclassifications			(5,051)
Amounts reclassified from accumulated other comprehensive loss			0
Total other comprehensive income (loss), net of tax			(5,051)
Ending balance	(29,020)		(29,020)
Unrealized Gains (Losses) on Investments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance			465
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Other comprehensive loss before reclassifications			702
Amounts reclassified from accumulated other comprehensive loss			455
Total other comprehensive income (loss), net of tax			1,157
Ending balance	1,622		1,622
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(34,179)	(30,740)	(23,504)	(33,000)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Total other comprehensive income (loss), net of tax	6,781	(5,040)	(3,894)	(2,780)
Ending balance	$ (27,398)	$ (35,780)	$ (27,398)	$ (35,780)