Property and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 79,425	$ 61,822
Less: accumulated depreciation and amortization	(41,144)	(30,503)
Property and equipment, net	38,281	31,319
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	32,852	29,501
Computer equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	21,522	18,369
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	6,127	5,211
Computer Software Purchased
Property, Plant and Equipment [Line Items]
Property and equipment, gross	6,083	5,847
Computer software developed for internal use
Property, Plant and Equipment [Line Items]
Property and equipment, gross	12,069	721
Fixed assets in progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 772	$ 2,173