Net Revenues and Long Lived Assets by Geographic Area (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013		Dec. 31, 2013
Segment Reporting Information [Line Items]
Net revenues	$ 228,250	[1]	$ 202,501	[1]	$ 447,773	[1]	$ 391,607	[1]
Long-lived assets	113,317	[2]			113,317	[2]			110,511	[2]
North America
Segment Reporting Information [Line Items]
Net revenues	207,679	[1],[3]	186,839	[1],[3]	407,380	[1],[3]	360,126	[1],[3]
Long-lived assets	2,548	[2],[3]			2,548	[2],[3]			2,713	[2],[3]
India
Segment Reporting Information [Line Items]
Net revenues	512	[1]	285	[1]	916	[1]	640	[1]
Long-lived assets	109,221	[2]			109,221	[2]			106,133	[2]
Europe
Segment Reporting Information [Line Items]
Net revenues	19,037	[1],[4]	14,127	[1],[4]	37,489	[1],[4]	28,102	[1],[4]
Long-lived assets	89	[2],[4]			89	[2],[4]			72	[2],[4]
Rest of the World
Segment Reporting Information [Line Items]
Net revenues	1,022	[1]	1,250	[1]	1,988	[1]	2,739	[1]
Long-lived assets	$ 1,459	[2]			$ 1,459	[2]			$ 1,593	[2]

[1] Net revenues are attributed to regions based upon customer location.

[2] Long-lived assets include property and equipment, net of accumulated depreciation and amortization, and goodwill.

[3] Primarily relates to operations in the United States.

[4] Primarily relates to operations in the United Kingdom.