Condensed 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
Net (loss) income	$ (18,548)	$ (48,491)	$ (86,147)	$ 34,460
Other comprehensive loss:
Foreign currency translation adjustments	1,467	(15,059)	325	(9,045)
Unrealized gain (loss) on marketable securities and restricted investments, net of tax of $(417), $41, $560, and $3,151	11,905	506	8,558	(25,418)
Unrealized (loss) gain on derivative instruments, net of tax of $358, $(914), $331, and $(978)	(1,279)	2,899	(1,337)	1,967
Other comprehensive income (loss)	12,093	(11,654)	7,546	(32,496)
Comprehensive income (loss)	(6,455)	(60,145)	(78,601)	1,964
Unrealized gain (loss) on marketable securities and restricted investments, tax	(417)	41	560	3,151
Unrealized (loss) gain on derivative instruments, tax	$ 358	$ (914)	$ 331	$ (978)