Accumulated Other Comprehensive Loss - Activity within Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ (19,883)	$ (23,315)	$ (14,031)
Other comprehensive income (loss)	(51,693)	3,432	(9,284)
Ending balance	(71,576)	(19,883)	(23,315)
Unrealized gain on available-for-sale securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	22,977
Other comprehensive income (loss)	(22,977)	22,977
Ending balance		22,977
Foreign currency translation [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(42,860)	(23,315)	(14,031)
Other comprehensive income (loss)	(28,716)	(19,545)	(9,284)
Ending balance	$ (71,576)	$ (42,860)	$ (23,315)