Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 402,835	$ 129,590	$ 1,077,308	$ 373,412
Other comprehensive income:
Foreign currency translation adjustments	(2,081)	5,678	6,049	22,604
Change in unrealized gains on available-for-sale securities, net of tax of $0, $212, $0, and $378, respectively	0	328	0	599
Total other comprehensive income (loss)	(2,081)	6,006	6,049	23,203
Comprehensive income	$ 400,754	$ 135,596	$ 1,083,357	$ 396,615