Carrying Amount of Amortizable Intangible Assets (Detail) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Finite-Lived Intangible Assets [Line Items]
Gross cost	$ 23,602	$ 23,602
Accumulated amortization	(15,804)	(10,018)
Net	7,798	13,584
Content
Finite-Lived Intangible Assets [Line Items]
Gross cost	10,634	10,634
Accumulated amortization	(10,634)	(7,089)
Net		3,545
Trade Name
Finite-Lived Intangible Assets [Line Items]
Gross cost	5,758	5,758
Accumulated amortization	(2,015)	(1,152)
Net	3,743	4,606
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Gross cost	7,210	7,210
Accumulated amortization	(3,155)	(1,777)
Net	$ 4,055	$ 5,433

Sum of the gross carrying amounts before accumulated amortization as of the balance sheet date of all intangible assets having statutory or estimated useful lives. The aggregate gross carrying amount (including any previously recognized impairment charges) of a major finite-lived intangible asset class. A major class is composed of intangible assets that can be grouped together because they are similar, either by their nature or by their use in the operations of a company.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 142

-Paragraph 45

-Subparagraph a(1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6905858&loc=d3e16323-109275

Name:	us-gaap_FiniteLivedIntangibleAssetsGross
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant