Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 113,915	$ 43,061	$ 221,045	$ 96,775
Other comprehensive income (loss):
Foreign currency translation adjustments	2,849	(24,558)	3,351	(18,275)
Change in unrealized gain (loss) on investments, net of income tax (provision) benefit of $(547), $(299), $(1,101) and $572 for the three and six months ended June 30, 2019 and 2018, respectively	1,646	921	3,077	(1,765)
Other comprehensive income (loss)	4,495	(23,637)	6,428	(20,040)
Comprehensive income	$ 118,410	$ 19,424	$ 227,473	$ 76,735