Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Net income	$ 208,949	$ (27,342)	$ 323,435	$ 49,130
Net income (loss)—basic	208,949	(27,342)
Unrealized gains (losses) on investments:
Unrealized holding gains (losses) arising during the period	(27,804)	20,239	(88,447)	27,606
Less: Reclassification adjustment for net gains (losses) included in net income	(1,336)	(1,167)	(4,468)	(2,798)
Net unrealized gains (losses) on investments	(26,468)	21,406	(83,979)	30,404
Unrealized foreign currency translation adjustments	0	74	3	108
Other comprehensive income (loss), net of tax	(26,468)	21,480	(83,976)	30,512
Comprehensive income	$ 182,481	$ (5,862)	$ 239,459	$ 79,642