Goodwill and Other Intangible Assets, Net (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended		12 Months Ended				3 Months Ended	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012	Dec. 31, 2011	Jun. 30, 2013 Variable Interest Entity, Primary Beneficiary [Member]	Dec. 31, 2012 Variable Interest Entity, Primary Beneficiary [Member]	Jun. 30, 2013 The Show [Member]	Jun. 30, 2012 The Show [Member]	Dec. 31, 2012 Steel Sports [Member]
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 59,168		$ 59,168		$ 53,093	$ 8,244	$ 3,600	$ 0
Amortization of intangibles	2,231	1,579	4,631	2,393
Goodwill, Impairment Loss			0		1,988				1,800	1,800	200
Goodwill, Impaired, Accumulated Impairment Loss	$ 1,988		$ 1,988		$ 1,988