Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement Of Partners Capital [Abstract]
Net income (loss)	$ 26,639	$ (108,173)	$ (121,510)
Other comprehensive income (loss):
Change in foreign currency translation adjustment	35,352	(76,410)	(23,480)
Net change in unrealized gains (losses) on available-for-sale marketable securities, net of tax	(155)	104	267
Other comprehensive income (loss), net of tax:	35,197	(76,306)	(23,213)
Comprehensive income (loss):	$ 61,836	$ (184,479)	$ (144,723)