Property and Equipment (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Property, Plant and Equipment [Line Items]
Property, plant and equipment, Gross	$ 69,856	$ 67,071
Less: accumulated depreciation and amortization	(41,706)	(32,558)
Property and equipment, net	28,150	34,513
Computers and equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, Gross	16,672	14,733
Software
Property, Plant and Equipment [Line Items]
Property, plant and equipment, Gross	33,603	32,982
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, plant and equipment, Gross	8,670	8,555
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, Gross	$ 10,911	$ 10,801