Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

Reference 1: 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=7658586&loc=d3e16323-109275

Reference 2: 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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

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- Definition

Amount of amortization expense expected to be recognized after the fifth fiscal year following the latest fiscal year for assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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- Definition

Amount of amortization expense expected to be recognized during the next fiscal year following the latest fiscal year for assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount of amortization expense expected to be recognized during the fifth fiscal year following the latest fiscal year for assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount of amortization expense expected to be recognized during the fourth fiscal year following the latest fiscal year for assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount of amortization expense expected to be recognized during the third fiscal year following the latest fiscal year for assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount of amortization expense expected to be recognized during the second fiscal year following the latest fiscal year for assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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- Definition

Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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- Definition

Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Goodwill and intangible assets (Details 2) (USD $) In Thousands, unless otherwise specified				12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Venue contracts	Dec. 31, 2011 Venue contracts	Dec. 31, 2012 Technology	Dec. 31, 2012 Advertiser relationships	Dec. 31, 2012 Patents, trademarks and other	Dec. 31, 2011 Patents, trademarks and other
Intangible assets
Weighted Average Amortization				11 years	11 years	5 years	5 years	5 years	6 years
Historical Cost	$ 28,905	$ 26,776		$ 26,886	$ 26,385	$ 1,110	$ 70	$ 839	$ 391
Accumulated Amortization	(18,311)	(16,930)		(17,783)	(16,874)	(93)	(6)	(429)	(56)
Net Book Value	10,594	9,846	11,251	9,103	9,511	1,017	64	410	335
Amortization expense for fiscal years 2013 through 2016 and thereafter
2013	1,220
2014	1,175
2015	1,127
2016	1,092
2017	970
Thereafter	5,010
Net Book Value	$ 10,594	$ 9,846	$ 11,251	$ 9,103	$ 9,511	$ 1,017	$ 64	$ 410	$ 335