Change in Accumulated Other Comprehensive Income (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2017 USD ($)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$ 168,764
Other comprehensive income	1,031
Ending Balance	176,791
Unrealized Gain (Loss) on Investments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(5)
Other comprehensive income	4
Ending Balance	(1)
Foreign Currency Translation Gain (Loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(13,744)
Other comprehensive income	1,027
Ending Balance	(12,717)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(13,749)
Ending Balance	$ (12,718)