Components of Other Income (Expense), Net (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Component Of Other Expense Income Nonoperating [Line Items]
Interest expense	$ (3,216)	$ (575)	$ (6,592)	$ (1,145)
Interest income on term deposits	93	3,581	225	7,485
Gain on sale of mutual funds, net	329	1,778	560	2,479
Miscellaneous income	40	91	173	152
Other income (expense), net	$ (2,754)	$ 4,875	$ (5,634)	$ 8,971