Geographical Information - Revenue by Geographical Area (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 741,420	$ 764,717	$ 690,410
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	507,473	506,268	426,906
All Other Countries [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 233,947	$ 258,449	$ 263,504