Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	$ 1,734,266	$ 1,636,550	$ 1,738,778	$ 1,593,147
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Other comprehensive loss before reclassifications			(10,892)
Amounts reclassified from accumulated other comprehensive loss			217
Net current-period other comprehensive loss	1,169	(2,020)	(10,675)	2,260
Ending balance	1,708,625	1,634,501	1,708,625	1,634,501
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			(12,136)
Amounts reclassified from accumulated other comprehensive loss			0
Net current-period other comprehensive loss			(12,136)
Ending balance	(36,105)		(36,105)
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			1,244
Amounts reclassified from accumulated other comprehensive loss			217
Net current-period other comprehensive loss			1,461
Ending balance	1,926		1,926
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(35,348)	(28,720)	(23,504)	(33,000)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Net current-period other comprehensive loss	1,169	(2,020)	(10,675)	2,260
Ending balance	$ (34,179)	$ (30,740)	$ (34,179)	$ (30,740)