Property and Equipment, Net - Components of Company's Property and Equipment (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 98,890	$ 106,582
Accumulated depreciation	(66,781)	(71,621)
Property and equipment, net	32,109	34,961
Leasehold improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	44,637	44,242
Office furniture, fixtures and equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	21,112	24,301
Computer equipment and software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 33,141	$ 38,039