Summary of Significant Accounting Policies (Details 3) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenue recognition
Revenues from barter transactions									$ 550,000	$ 477,000	$ 424,000
Percentage of gross broadcast rights fees retained by NASCAR	10.00%								10.00%
Percentage of gross broadcast rights fees recorded as revenue	90.00%								90.00%
Percentage of gross broadcast rights fees payable to the event as part of the awards to the competitors	25.00%								25.00%
Expense recognition
Advertising expenses									1,191,000	1,160,000	1,093,000
Net earnings per common share - basic:
Net earnings									3,145,000	2,024,000	4,571,000
Allocation to nonvested restricted stock awards									50,000	33,000	67,000
Net earnings available to common stockholders	(2,182,000)	2,601,000	4,844,000	(2,118,000)	(4,758,000)	4,158,000	4,903,000	(2,279,000)	3,095,000	1,991,000	4,504,000
Weighted-average shares outstanding									36,047,000	36,252,000	36,299,000
Net earnings per share - basic (in dollars per share)	$ (0.06)	$ 0.07	$ 0.13	$ (0.06)	$ (0.13)	$ 0.11	$ 0.13	$ (0.06)	$ 0.09	$ 0.05	$ 0.12
Net earnings per common share - diluted:
Net earnings (loss)									3,145,000	2,024,000	4,571,000
Allocation to nonvested restricted stock awards									50,000	33,000	67,000
Net earnings available to common stockholders									3,095,000	1,991,000	4,504,000
Weighted-average shares and dilutive shares outstanding									36,047,000	36,252,000	36,299,000
Net earnings per share - diluted (in dollars per share)	$ (0.06)	$ 0.07	$ 0.13	$ (0.06)	$ (0.13)	$ 0.11	$ 0.13	$ (0.06)	$ 0.09	$ 0.05	$ 0.12
Options outstanding (in shares)	0				0				0	0	0
Accounting for stock-based compensation
Stock-based compensation expense									278,000	291,000	313,000
Income tax benefit (expense) related to restricted stock awards											(4,000)
Restricted Stock
Accounting for stock-based compensation
Stock-based compensation expense									278,000	291,000	313,000
Income tax benefit (expense) related to restricted stock awards									$ 113,000	$ 56,000		$ (4,000)