Note 10 - Segment Disclosures - Summary of Intangible Assets and Goodwill (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Other intangibles	$ 298,383	$ 298,383
Goodwill	46,225	46,225
Total assets	1,458,287	1,426,360
Motorsports Event Segment [Member]
Other intangibles	298,383	298,383
Goodwill	46,225	46,225
Total assets	1,433,738	1,402,474
Other Segments [Member]
Other intangibles
Goodwill
Total assets	$ 24,549	$ 23,886