Related Party Transactions (Details) (USD $)			1 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended
	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2012 Dover facility	May 31, 2011 Dover facility	Jun. 30, 2012 Dover facility	Jun. 30, 2011 Dover facility	Jun. 30, 2012 Dover facility	Jun. 30, 2011 Dover facility	Jun. 30, 2012 Dover Downs Gaming & Entertainment, Inc item	Jun. 30, 2011 Dover Downs Gaming & Entertainment, Inc	Jun. 30, 2012 Dover Downs Gaming & Entertainment, Inc item	Jun. 30, 2011 Dover Downs Gaming & Entertainment, Inc mile	Dec. 31, 2011 Dover Downs Gaming & Entertainment, Inc	Jun. 30, 2012 Henry B. Tippie
Related Party Transactions
Costs for administrative and operating services, including leased space allocated by related party			$ 376,000	$ 416,000					$ 512,000	$ 559,000	$ 933,000	$ 997,000
Administrative and operating service costs allocated to related party					143,000	150,000	239,000	246,000	46,000	133,000	129,000	201,000
Amount payable to Gaming	2,000								2,000		2,000
Amount receivable from Gaming		$ 11,000											$ 11,000
Length of harness racing track used (in miles)												0.625
Length of motorsports superspeedway of entity (in miles)												1
Period, before and after the period of exclusive use of harness track, for which related party has set up and tear down rights (in weeks)									2		2
Number of annual motorsports weekends for which use of indoor grandstands is allowed by related party									2		2
Minimum percentage of voting power controlled by related party														50.00%
Minimum percentage of voting power of Gaming controlled by other related party														50.00%