Property and Equipment, Net - Property and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 174,962	$ 144,291
Less: accumulated depreciation and amortization	(101,458)	(77,322)
Property and equipment, net	73,504	66,969
Furniture, fixtures and equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	22,074	18,472
Computer equipment and software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	127,454	101,721
Telecommunications equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	4,029	3,956
Leasehold improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	19,711	17,964
Other [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 1,694	$ 2,178