Property and Equipment (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Property, plant and equipment, Gross	$ 76,119	$ 69,713
Less: accumulated depreciation and amortization	(48,447)	(41,715)
Property and equipment, net	27,672	27,998
Computers and equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, Gross	16,414	14,675
Software
Property, Plant and Equipment [Line Items]
Property, plant and equipment, Gross	37,062	34,467
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, Gross	12,906	11,493
Furniture and Fixture
Property, Plant and Equipment [Line Items]
Property, plant and equipment, Gross	$ 9,737	$ 9,078