Commitments and Contingencies (Details) (USD $)	3 Months Ended		12 Months Ended		1 Months Ended				3 Months Ended		12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012 Sports Authority of the County of Wilson (Tennessee)	Mar. 31, 2013 Sports Authority of the County of Wilson (Tennessee)	Sep. 30, 1999 Variable Rate Tax Exempt Infrastructure Revenue Bonds, Series 1999 Sports Authority of the County of Wilson (Tennessee)	Mar. 31, 2013 Variable Rate Tax Exempt Infrastructure Revenue Bonds, Series 1999 Sports Authority of the County of Wilson (Tennessee)	Mar. 31, 2013 Variable Rate Tax Exempt Infrastructure Revenue Bonds, Series 1999 Minimum Sports Authority of the County of Wilson (Tennessee)	Mar. 31, 2013 Variable Rate Tax Exempt Infrastructure Revenue Bonds, Series 1999 Maximum Sports Authority of the County of Wilson (Tennessee)	Mar. 31, 2013 Nashville Superspeedway Variable Rate Tax Exempt Infrastructure Revenue Bonds, Series 1999	Mar. 31, 2012 Nashville Superspeedway Variable Rate Tax Exempt Infrastructure Revenue Bonds, Series 1999	Dec. 31, 2011 Nashville Superspeedway Variable Rate Tax Exempt Infrastructure Revenue Bonds, Series 1999
Commitments and Contingencies
Debt issued					$ 25,900,000
Outstanding amount of debt						19,600,000
Annual principal payments							800,000	1,600,000
Irrevocable direct-pay letter of credit issued						19,929,000
Balance available in the sales and incremental property tax fund			1,758,000	2,722,000
Amount paid into the sales and incremental property tax fund			957,000
Deduction from the sales and incremental property tax fund for principal and interest payments			733,000
Provision for contingent obligation	(22,000)	(40,000)									2,250,000
Decrease in the provision for contingent obligation due to changing interest rates									22,000	35,000
Reserve of contingent obligation									$ 1,912,000