Goodwill and Other Intangible Assets, Net (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended				9 Months Ended	6 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Dec. 31, 2011	Sep. 30, 2013 Variable Interest Entity, Primary Beneficiary [Member]	Dec. 31, 2012 Variable Interest Entity, Primary Beneficiary [Member]	Sep. 30, 2012 The Show [Member]	Dec. 31, 2012 Steel Sports [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	$ 1,985	$ 2,635	$ 6,616	$ 5,028
Goodwill, Impairment Loss			0		(1,988)				1,800	200
Goodwill	59,164		59,164		53,093	8,244	3,600	0
Goodwill, Impaired, Accumulated Impairment Loss	$ 1,988		$ 1,988		$ 1,988