Stockholder's Equity - Components of Accumulated Other Comprehensive Income (Loss) included in Stockholders' Equity (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Stockholders Equity Note [Abstract]
Foreign currency translation adjustments ("CTA")	$ (49,621)	$ (49,025)
Net unrealized gain on investments	400	393
Net unrealized loss on derivative financial instruments	(1,586)	(1,816)
Accumulated other comprehensive loss	$ (50,807)	$ (50,448)