Schedule of Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance			$ 494,644
Changes before reclassifications			13,876	$ 2,729
Current period other comprehensive income	$ 11,817	$ (7,775)	13,876	2,729
Ending Balance	521,976		521,976
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance			(67,735)	(60,190)
Changes before reclassifications			14,546	4,956
Current period other comprehensive income			14,546	4,956
Ending Balance	(53,189)	(55,234)	(53,189)	(55,234)
Unrealized Losses of Available for Sale Securities
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance			(2,693)	(703)
Changes before reclassifications			(670)	(2,227)
Current period other comprehensive income			(670)	(2,227)
Ending Balance	(3,363)	(2,930)	(3,363)	(2,930)
AOCI Attributable to Parent
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance			(70,428)	(60,893)
Ending Balance	$ (56,552)	$ (58,164)	$ (56,552)	$ (58,164)