Carrying Amounts of Amortizable Intangible Assets (Parenthetical) (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012		Dec. 31, 2011
Finite-Lived Intangible Assets [Line Items]
Gross cost	$ 21,630	[1]	$ 12,968
Trade Name
Finite-Lived Intangible Assets [Line Items]
Gross cost	6,006	[1]	5,758
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Gross cost	10,468	[1]	7,210
Intangible assets, useful life (years)	4 years
content
Finite-Lived Intangible Assets [Line Items]
Gross cost	3,269	[1]
Intangible assets, useful life (years)	4 years
Software
Finite-Lived Intangible Assets [Line Items]
Gross cost	1,887	[1]
Intangible assets, useful life (years)	3 years
Minimum | Trade Name
Finite-Lived Intangible Assets [Line Items]
Intangible assets, useful life (years)	2 years
Maximum | Trade Name
Finite-Lived Intangible Assets [Line Items]
Intangible assets, useful life (years)	5 years
Ideas International Limited
Finite-Lived Intangible Assets [Line Items]
Gross cost	8,400
Ideas International Limited | Trade Name
Finite-Lived Intangible Assets [Line Items]
Gross cost	200
Ideas International Limited | Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Gross cost	3,200
Ideas International Limited | content
Finite-Lived Intangible Assets [Line Items]
Gross cost	3,200
Ideas International Limited | Software
Finite-Lived Intangible Assets [Line Items]
Gross cost	$ 1,800

[1] The Company acquired Ideas International in the second quarter of 2012 and recorded $8.4 million of amortizable intangible assets, allocated as follows: Trade Name-$0.2 million; Customer Relationships-$3.2 million; Content-$3.2 million; and Software-$1.8 million.