Schedule of Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	$ 494,644
Changes before reclassifications	2,059	$ 10,504
Current period other comprehensive income	2,059	10,504
Ending Balance	498,419
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(67,735)	(60,190)
Changes before reclassifications	2,630	12,541
Current period other comprehensive income	2,630	12,541
Ending Balance	(65,105)	(47,649)
Unrealized Losses of Available for Sale Securities
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(2,693)	(703)
Changes before reclassifications	(571)	(2,037)
Current period other comprehensive income	(571)	(2,037)
Ending Balance	(3,264)	(2,740)
AOCI Attributable to Parent
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(70,428)	(60,893)
Ending Balance	$ (68,369)	$ (50,389)